Environmental factors and genetic parameters of growth traits in Tunisian local sheep

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It involved 45780 lambs in 134 flocks from 99 farms. The zootechnical data (live weight, average daily gain) for the period 2011–2016 were obtained from the C of Genetic Improvement of the Office of Livestock and Pastures in Sidi Thabet. The results obtained showed a significant difference in weight and daily gains at typical ages. Lambs from single births were heavier than lambs from double births (1.05 ± 0.14 and 1 ± 0,01 kg). ADGs were influenced by the sex-mode of birth (P < 0.05). Single-born lambs showed higher ADGs, followed by twice-born lambs. The genetic type factor significantly influenced the growth of the lambs (P < 0.05). However, it should be noted that performance (weight growth and average daily gain) was better at the QFO breed. The age of the dams showed higher ADGs in lambs from dams aged 3 to 4 years, while the lowest ADGs were recorded in lambs from dams aged 5 years and older. The heritability coefficients of weights at different ages were estimated at 0.16 ± 0.04 for ADG3060 and 0.48 ± 0.03 for W10. The lowest values were observed for the ADG3060 (0.16 ± 0.021). The highest value is obtained for P10. Estimates of the genetic correlation for W10 with other parameters (W60, ADG0030, and ADG3060) were of the order of 14–42% of the variability. genetic performances sheep growth heritability Introduction The Tunisian indigenous sheep (Ovis aries) population is critical to the country's agriculture and economy, providing a significant supply of meat and wool while also playing an important role in conserving small ruminant genetic diversity. There has been a rising interest in increasing the production potential of these indigenous sheep breeds throughout the years. Understanding the variables that determine their growth features, particularly the connections between environmental and genetic elements, is critical for developing and executing effective breeding and management techniques to promote productivity and adaptability. Tunisian indigenous sheep breeds, which have adapted to a variety of environmental situations, are an important genetic resource. Understanding the complex interplay between genetic elements and environmental variables determining growth qualities in these native sheep breeds is critical for conservation and breeding initiatives. A complex combination of genetic and environmental variables influences sheep growth performance, including body weight, average daily increase, and other morphometric features. Nutrition, environment, and management techniques all interact with the genetic composition of the animals, influencing their growth and development. Several studies have emphasized the importance of environmental and genetic variables in defining development features in distinct sheep populations (Ben Sassi et al., 2019; Bouraoui et al., 2016). However, the particular interconnections of these elements and their influence on Tunisian native sheep breeds are still mostly unknown. Altitude, temperature, precipitation, and available pasture are known to have a substantial impact on sheep breeds' growth performance and adaptability (Ammar et al., 2018). Furthermore, genetic variation within and across Tunisian sheep breeds can have a significant influence on growth features and adaptation to local environments (Hajji et al., 2017). Numerous studies conducted across the world have proved the importance of environmental factors in affecting the development potential of sheep breeds (Notter, 2012; Salgado et al., 2015). Nutrition has been highlighted as a critical environmental element that determines development features because it directly affects the availability of vital nutrients and energy required for growth (NRC, 2007). Furthermore, environmental factors such as temperature, humidity, and the photoperiod can influence thermoregulation, feed intake, and nutrient utilization in sheep (Sawalha et al., 2017). Understanding the effect of environmental and genetic variables on growth parameters in Tunisian indigenous sheep is crucial for creating long-term breeding plans that take genetic diversity and environmental adaptability into account. This study may have implications not just for the preservation of indigenous genetic resources but also for increasing cattle output in Tunisian agricultural systems. When evaluating growth qualities in Tunisian indigenous sheep, genetic factors are equally important. Genetic selection algorithms may be adjusted to promote desired features, thereby increasing population genetic development (Gutiérrez and Goyache, 2005). Understanding the heritability of these qualities, as well as the genetic links between individuals, might help breeders make better judgments about how to optimize growth potential while conserving genetic variety (Falconer and Mackay, 1996). The purpose of this study is to investigate the links between environmental influences and genetic characteristics, specifically how they impact growth features in Tunisian indigenous sheep. This study aims to give insights that might lead to the development of appropriate breeding and management techniques to improve the growth performance and resilience of these indigenous sheep breeds by performing a complete analysis. Materials and methods Data The research was based on a data set comprised of growth checks performed on 134 herds between 2011 and 2016. The information gathered came from Sidi Thabet's Centre National d''Amélioration Génétique. Four breeds (BTN, BTR, QFO, and NT) were considered, totaling 45780 individuals. The farm code, flock number, animal number, sex and method of birth, month of birth, year of birth, mother number, mother's month and year of birth, weighing dates, and weights were all supplied for each lamb. Table 1 reflects the features of the data files examined. Table 1 Characteristics of the data used Periods 2011- 2016 Mothers 19789 Herds 134 Farms 99 Data 45780 Calculating weights and weight gains at typical ages Weights at typical ages (WTA): 10 days (W10), 30 days (W30), and 60 days (W60) were estimated based on periodic weighings, and average daily gains between 10 and 30 days (ADG10-30) and between 30 and 60 days (ADG30-60) were calculated. Weights at standard ages (W10, W30, and W60) are determined using two methods based on the collected data: either the standard age is between two subsequent weighings, in which case linear interpolation is used. Extrapolation is used if the standard age does not fall between two weighings. The formula used in both circumstances is as follows: W x = Wn -1 - ((Wn-Wn-1) /(Dn-Dn-1)) (Dn-1-Dx) Where: WX is the weight after 10, 30, and 60 days. DX Date: 10, 30, or 60 days old. Pn and Wn-1 are the two weighings needed to determine W, while Dn and Dn-1 are the matching dates. ADG at normal ages is computed in grams as follows: ADG00-30 = (W30-WN) /30 ADG30-60= (W60-W30) /30 Statistical Analyses Data were analyzed using SAS software version 9.4 (Statistical Analysis System, Release 9.4 2012; SAS Institute Inc., Cary, NC, USA). The mean effects of the factors of variation were estimated by the "Least Squares" method, using the LSmeans (Least Square Means) instruction. The model used to study the variability of the parameters considered (P10, P30, W60, ADG00-30, and ADG30-60) is as follows: Y ijkl = µ + MBi + YBj+ AM k + SMl + Bm+ e ijklmn Where:Y ijkl is the performance of the nth lamb, µ is the overall mean. MBi is the fixed effect of the month of birth (i = 1-6), YBj is the fixed effect of the jth year of birth (j = 2011–2016), and AMk is the fixed effect of the kth age of the mother (k = 2–8, AM ≥ 9 years). SMl is the fixed effect of the lth sex mode of birth (l = 1-4). Bm is the fixed effect of the mth breed (m = 1-4), and Eijklmn is the random error relating to the e ijklmth observation. Differences between means according to the factors studied were analyzed using the SNK (Student-Newman-Keuls) test. Genetic parameters An animal model with direct and maternal genetic influences is used to assess genetic components. The model comprises fixed characteristics (herd-year, sex-mode, mother’s age, and month of birth) as well as four random elements, the first two of which are associated (direct and maternal genetic impacts), and the final two of which are independent (effect of the permanent environment and residual effect). The Devirative-Free Restricted Maximum Likelihood (DF-REML) method was used to estimate covariance components, which was based on a simple animal model with direct genetic effects, including the fixed effects of herd year, month of birth, sex-mode of birth, and maternal age, and was run on VCE 4.2.5 software (Neumeier and Groeneveld, 1998). Results Results of analysis of variances The factors studied have significant effects on variation in weight at 10 days (W10), weight at typical ages (W30 and W60), and ADG00-30 and ADG30-60. Spring-born lambs were heavier at birth and had higher weights at typical ages (30 and 60 days) than winter, autumn, and summer-born lambs. As a result, they recorded higher growth rates (ADG 0–30 and ADG 30–60). Compared with females, males show superiority in terms of weight at 10 days (W10), weight at typical ages (W30 and W60), and ADG0-30 and ADG30-60. Litter size had an influence (P < 0.05) on W10, weights at typical ages (W30 and W60), and average daily gains (ADG00-30 and ADG30-60). The values calculated for single lambs are greater (P < 0.05) than for double and triplet lambs. ANOVA results showed that lambs born to the youngest dams had the lowest performance (P < 0.05) compared with lambs born to the oldest dams (≥ 5 and over) (Table 2). Table 2 Variation Factors of Growth Performance Traits Variation factors W10 (kg) W30 (kg) W60 (kg) ADG0030 (g/d) ADG3060 (g/d) YB *** *** *** *** *** MB ** *** ** *** *** B BTN BTR NTB QFO ** ** ** *** *** 7.74± 0,13 b 7.90± 0.15 b 11.54± 0.23 b 147.98± 4.28 b 126.62± 5.02 b 8.17 ±0,14 ab 8.39± 0.12 a 13.01± 0.22 a 169.71± 4.17 a 154.09± 4.89 a 8.43± 0.14 a 8.52 ± 0.12 a 13.54 ± 0.22 a 167.54 ± 4.20 a 167.16 ± 4.92 a 8.62± 0.15 a 8.41± 0.13 a 12.38 ± 0.23 ab 170.58± 4.39 a 132.08± 5.15 b SM 11 12 21 22 ** *** *** ** ** 9.25± 0.14 a 9.29 ± 0.12 a 14.04 ± 0.22 a 181.61 ± 4.19 a 158.12± 4.92 a 7.70± 0,15 b 7.63± 0,12 ab 11.76 ± 0.22 b 152.80 ± 4.29 b 137.65 ± 5.03 ab 8.85 ±0.15 ab 8.86± 0.13 a 13.43± 0.22 ab 173.84± 4.19 a 152.21± 4.91 a 7.33 ±0.15 b 7.27± 0.11 b 11.23± 0.23 b 147.56± 4.27 b 131.97± 5.01 b AM 2 3 4 >5 ** *** *** *** ** 7.64 ± 0.15 b 7.71± 0.12 b 11.79± 0.22 b 145.62± 4.27 c 135.84± 5.01 c 8.41 ± 0.15 a 8.37± 0.13 a 12.76± 0.23 ab 167.52± 4.25 b 146.09± 4.99 b 8.53 ± 0.14 a 8.48± 0.12 a 12.97± 0.22 a 171.15± 4.24 a 149.65± 4.97 a 8.55 ± 0.15 a 8.48± 0.12 a 13.07± 0.22 a 170.98± 4.26 a 152.97± 4.99 a ∗∗ P < 0.01; ∗∗∗ P 0.05). Values with different letters (per column) are significantly different (P < 0.05). AM=age of mother; YB=year of birth; MB=month of birth; B=breed; BTN=Black-headed Barbarine; BTR=red-head Barbararine; NTB=Noire de Thibar; QFO=Queue fine de l’Ouest; SM=sex mode of birth; WB=weight at birth; P30 =weight at 30 days; P60 =weight at 60 days; ADG00-30 =average daily gain between 0 and 30 d; ADG 30-60=average daily gain between 30 and 60 d. Effects of breed on growth performance The mean values (± SD) of the lambs' weights at typical ages and average daily gains are shown in Table 3. P10 ranged from 5.73±2.62 to 7.54±2.72kg. The highest value was for the QFO breed. Table 3 Average performance by breed Traits W10 (kg) W30 (kg) W60 (kg) ADG0030 (g/d) ADG3060 (g/d) Breed BTN BTR NTB QFO ** ** ** *** *** 7.74± 0.13 b 7.90± 0.15 b 11.54± 0.23 b 147.98± 4.28 b 126.62± 5.02 b 8.17 ±0.14 ab 8.9± 0.12 a 13.01± 0.22 a 169.71± 4.17 a 154.09± 4.89 a 8.43± 0.14 a 8.52 ± 0.12 a 13.54 ± 0.22 a 167.54 ± 4.20 a 167.16 ± 4.92 a 8.62± 0.15 a 8.41± 0.13 a 12.38 ± 0.23 ab 170.58± 4.39 a 132.08± 5.15 b BTN , BTR, NTB, QFO; W10= weight at 10 days; W30 =weight at 30 days; W60 = weight at 60 days; ADG0030 = average daily gain between 0 and 30 days; ADG3060= average daily gain between 30 and 60 days Effect of mode of birth on growth performance Single-born lambs achieved higher weights and ADG than double-born lambs. These differences changed with age (Table 4). As an indication, single-born males had respective W10, W30, and W60j of 8.68±2.59, 8.98±2.28, and 13.63±3.95 kg, whereas double-born males recorded respective weights of 8.26±2.42, 8.3±1.93, and 11.6±3.64 kg during the same typical ages. Table 4 Effect of mode of birth on growth performance Traits W10 (kg) W30 (kg) W60 (kg) ADG00-30 (g/j) ADG30-60 (g/j) SM 11 12 21 22 ** *** *** ** ** 9.25± 0.14 a 9.29 ± 0.12 a 14.04 ± 0.22 a 181.61 ± 4.19 a 158.12± 4.92 a 7.70± 0.15 b 7.63± 0.2 ab 11.76 ± 0.22 b 152.80 ± 4.29 b 137.65 ± 5.03 ab 8.85 ±0.15 ab 8.86± 0.13 a 13.43± 0.22 ab 173.84± 4.19 a 152.21± 4.91 a 7.33 ±0.15 b 7.27± 0.11 b 11.23± 0.23 b 147.56± 4.27 b 131.97± 5.01 b Effect of the mother’s age on growth performance W10 and W30 were impacted by the age of the mother (P<0.001), as well as ADG00-30 and ADG30-60 (P<0.05) (table 5). Lambs born to two-year-old ewes weighed 0.77, 0.65, and 0.99 kg less than those born to three-year-old ewes and 0.8, 0.65, and 1.51 kg less than the averages for lambs born to five-year-old ewes. The ADG0030 and ADG3060 discrepancies are 22.678 and 10.81 g, respectively, to the detriment of lambs born to two-year-old moms. Lambs born to two-year-old mothers develop at a 14.07% slower rate than the herd average between 0 and 30 days. Table 5 Growth performance according to maternal age Traits Effects W10 (kg) W30 (kg) W60 (kg) ADG0030 (g/j) ADG3060 (g/j) AM 2 3 4 >5 ** *** *** *** ** 7.64 ± 0.15 b 7.71± 0.12 b 11.79± 0.22 b 145.62± 4.27 c 135.84± 5.01 c 8.41 ± 0.15 a 8.37± 0.13 a 12.76± 0.23 ab 167.52± 4.25 b 146.09± 4.99 b 8.53 ± 0.14 a 8.48± 0.12 a 12.97± 0.22 a 171.15± 4.24 a 149.65± 4.97 a 8.55 ± 0.15 a 8.48± 0.12 a 13.07± 0.22 a 170.98± 4.26 a 152.97± 4.99 a Performance by year of birth Table 6 displays the least squares of the influence of the lambing year. All attributes tested from birth to weaning were impacted by the year of birth (P< 0.05). Between 2011 and 2016, all growth parameters (W10, W30, W60, ADG 00-30, and ADG 30-60) increased by 7.67, 9.88, 11.88, 143.47, 133.41, 8.21, 9.43, 12.93, 161.99, and 149.95, respectively. Remembering the large interannual variation in rainfall. Table 6 Growth performance by year of birth YB N Obs Variable Mean SD Min Max 2011 12690 W10 W30 W60 ADG0030 ADG3060 7.67 9.88 11.88 143.47 133.41 2.46 2.11 3.92 68.34 91.83 3.21 4.8 9.7 - - 9 17 34 - - 2012 2269 W10 W30 W60 ADG0030 ADG3060 7.84 8.42 13.15 162.68 157.57 2.07 2.07 3.46 64.28 60.15 2 3 3.1 - - 9 15.6 24.1 - - 2013 8045 W10 W30 W60 ADG0030 ADG3060 8.95 9.39 14.78 192.91 179.52 2.71 2.33 3.95 74.23 79.72 1 3 3.4 - - 9 20 32.7 233 217 2014 10314 W10 W30 W60 ADG0030 ADG3060 8.02 7.921 12.26 145.42 144.87 2.53 2.03 3.51 64.34 69.06 1 5.8 7.9 - - 9.1 17.8 33.3 268 221 2015 4171 W10 W30 W60 ADG0030 ADG3060 8.31 9.37 13.07 161.58 156.54 2.44 2.07 3.36 64.93 61.91 4.14 5.18 6.8 97.45 76.32 9.3 17,1 27,3 241 228 2016 8291 W10 W30 W60 ADG0030 ADG3060 8.21 9.43 12.93 161.99 149.95 2.46 2.34 3.71 75.91 81.1 5.21 6.8 9.8 - - 9.23 19.9 32.6 256 249 Effect of birth month on Performance Analysis of the effect of lambing month on lamb growth indicated that this factor was an important source of variation in typical age weights and average daily gains (table 7). Table 7 Growth performance by month of birth MB N Obs Variable Means SD Min Max 7 43 43 43 43 43 W10 W30 W60 ADG0030 ADG3060 10.54 11.83 16.69 236.81 204.83 1.52 1.88 3 63.11 77.08 7 5. 8 9.1 86 60 15 14.1 27.2 351 530 8 3554 3554 3554 3554 3554 W10 W30 W60 ADG0030 ADG3060 8.05 9.23 12.97 150.25 163.70 2.81 2.1 4.28 67.74 106,41 1 2.8 2.8 0 0 20 19.9 33.2 556 849 9 21790 21790 21790 21790 21790 W10 W30 W60 ADG0030 ADG3060 7.90 8 12.48 148.83 149.08 2.6 2.17 3.94 69.63 85.88 1 2.8 2.8 0 0 23.3 20 34 533 836 10 19097 19400 19400 19400 19400 W10 W30 W60 ADG0030 ADG3060 8.18 8.71 13.22 170.211 150.3 2.32 2.24 3.63 72.19 68.69 0.1 2.8 3 0 0 20 19.2 28.2 506 594 11 965 984 984 984 984 W10 W30 W60 ADG0030 ADG3060 8.32 8.75 12.68 170.87 131.05 2.7 2.53 3.46 82.67 56.98 2 2.8 3.8 0 0 18 18.6 26.6 500 406 12 965 984 984 984 984 W10 W30 W60 ADG0030 ADG3060 6.18 8.01 11.91 144.55 129.88 1.3 1.55 2.18 49.66 36.75 4.6 6 9.4 80 80 8.8 10.8 15.6 238 207 Correlation between growth parameters All phenotypic correlations (Table 8). between body weights were positive and high (P ≤ 0.01)). Table 8 : Phenotypic correlations of lamb growth traits W10 W30 W60 ADG0030 ADG3060 W10 1 0.82 0.66 0.82 0.31 W30 1 0.81 0.98 0.37 W60 1 0.80 0.84 ADG0030 1 0.37 ADG3060 1 Genetic parameters Héritability Growth performance heritability coefficients are presented in Table 9. Heritability estimates are low overall, ranging from 0.16 ± 0.04 for ADG3060 to 0.48 ± 0.03 for W10. Table 9 Estimates of covariance components and genetic parameters of different growth parameters σ 2 a σ 2 r σ 2 p h 2 ±SD BTN W10 0.11 0.12 0.23 0.48 ± 0.03 W30 1.82 4.42 6.24 0.29 ± 0.05 W60 2.64 6.55 9.20 0.29 ± 0.048 ADG0030 169.25 480.98 650.22 0.26 ± 0.05 ADG3060 72.47 394.57 467.04 0.16 ± 0.04 BTR W10 2.55 5.85 8.40 0.30 ± 0.079 W30 2.37 5.82 8.19 0.29 ± 0.091 W60 1.86 0.47 6.41 0.29± 0.032 ADG0030 55.39 122.68 178.07 0.31 ± 0.064 ADG3060 96.47 401.57 507.73 0.19 ± 0.07 QFO W10 0.05 0.13 0.23 0.23 ± 0.052 W30 1.71 4.16 6.28 0.27 ± 0.05 W60 2.60 6.28 9.24 0.28 ± 0.049 ADG0030 164.68 461.80 653.02 0.25 ± 0.051 ADG3060 72.56 394.50 467.06 0.16± 0.021 NT W10 2.36 5.83 8.19 0.29± 0.012 W30 3.92 4.97 8.49 0.46± 0.031 W60 6.30 3.88 9.20 0.68± 0.051 ADG0030 133.31 362.63 466.77 0.29± 0.021 ADG3060 55.41 122.66 178.07 0.31± 0.042 σ 2 a , σ 2 r σ 2 p , are additive genetic variance, residual variance, résiduelle et phénotypic variance, h 2 ± SD= heritability (± SD) Genetic correlation Genetic correlations between weights are higher the closer the ages considered (Table 10). Table 10 Genetic correlations of different growth parameters W10 W30 W60 ADG0030 ADG3060 W10 - 0.75 0.42 0.34 0.14 W30 - 0.82 0.67 0.28 W60 - 0.63 0.34 ADG0030 - 0.37 ADG3060 - Discussions Variation factors of growth performance The similarity of results between the four seasons could be a form of adaptation to farming practices in the study region, where animals are kept in permanent stalls. They are always protected from the cold and heat of summer. Lambing season was a highly significant influencing factor (P<0.001) for all the growth parameters studied (weights at standard ages and corresponding ADGs, except ADG 70–90). The effect of the season of birth is felt in the evolution of lamb weights since lambs born in spring have higher weights at standard ages than lambs born in other seasons. These results are in line with those of Rekik et al. (2008) and Derquaoui (2003), who found that ewe lambs born in summer were heavier (27 kg) than those born in winter (25 kg). Similarly, Chniter et al. (2011) and Rekik et al. (2008) showed that the season of birth has a significant effect on the growth of D'Man lambs. In the present study, the ewe’s age affected lamb weights and ADGs. The weights of lambs in the two-year-old group were lower (P < 0.001) than those in the 3 to 5+ age groups. Indeed, lamb weights increased with maternal age. In addition, the ADG of these lambs was significantly lower than that of lambs born to ewes aged 4 and 5 years. Our results are in line with those of Saghi et al. (2007) and Koncagül et al. (2013). In another study, the age of the ewe did not affect the lamb birth weight, but 2 and 7-year-old ewes tended to wean lighter lambs (Ray and Smith, 1966). However, some researchers were unable to find significant differences between ewe age groups in terms of lamb birth and weaning weights (Cemal et al., 2005; Aliyari et al., 2012; Aktas and Dogan, 2014). Indeed, less developed mammary glands and, consequently, insufficient milk production for their lambs may be at the root of the 2-year-old ewe's lamb weight reduction. In line with several studies (Saghi et al., 2007; Koncagül et al., 2013; Aktas and Dogan, 2014), sex and mode of birth have a significant effect (P<0.001) on weights at typical ages and ADG of lambs, with an advantage for males and singletons over females and double lambs. Effects of breed P10 averaged 7.14 ± 2.48 kg, with extreme values ranging from 1 to 10.3 kg, reflecting considerable variability. Weight at 30 days ranged from 8.58 ±2.13 kg in BTN to 9.47 ±2.2 kg in BTR. Weight at 60 days varied between 11.15±3.44 and 13.22±3.83 kg in the BTN and NTB breeds. Attenuated growth rates (ADG 0–30 and ADG 30–60) are equal to 153.13±71.89 and 140.34±77.21 g/d, respectively. Similarly, Ben Hamouda and Othmane (2011) reported significant digital productivity in terms of an average number of lambs (1,8) up to weaning. They reported that, on average, Barbarine lambs weigh 4.2±0.4; 5.37±1.32; 8.29±2.1; 14.04± 3.46; and 16.28± 3.83 kg at 0, 10, 30, 70, and 90 days. The results obtained in this study for weight at various ages of the Barbarine breeds are comparable to those obtained by other authors who have worked on the same race (Ben Gara, 2000; Rabhi, 2003; and Maaoui et al., 2016). Our results for the NTB and QFO breeds outperform those of Ben Salem et al. (2009), who found average weights for the same breeds at 10 and 30 days after lambing of 6 ± 2 and 10 ± 3 kg, respectively, and Rekik et al. (2005), who reported a W10d of 7.32.48 kg for the QFE breed. Effect of mode of birth According to the results of the present study, we noted differences in favor of single lambs of the order of 0.42 kg at 10 days, 0.5 kg at 30 days, and 0.94 kg at 60 days. This is reflected in the weight gains corresponding to the different ages. However, Chniter et al. (2011) reported that the effect of birth mode on weight is most pronounced during the 10- to 30-day age period. The negative relationship between litter size and lamb growth is most often attributed to a reduced amount of milk available per lamb (Zidane et al., 2015). This is probably because for ewes with multiparous milk, although they produce more milk, the surplus quantity is insufficient to compensate for the increase in requirements. These results confirm those of Kerfal et al. (2005), who stated that birth weight decreases significantly with increasing litter size. This decrease in weight is also observed at later stages of growth through weaning. The slower growth in multiple-born lambs is the result of the mother's dairy capacity during the first month. It diminishes with age thanks to compensatory growth in multiple-born lambs during the post-weaning period. This shows that multiple-born lambs compensate for stunted growth early in life. Effect of the mother’s age Results showed that lambs born to the youngest dams had the lowest performance compared with lambs born to the oldest dams (≥ 5 and over). Kuchtk and Dobe (2006) and Macit et al. (2001) observed similar findings. Lambs from four-year-old and two-year-old moms had the highest and lowest values, respectively. Matika et al. (2003) discovered a similar pattern, whereas Dixit et al. (2001) discovered that lambs from two-year-old moms had the highest ADGs. Performance by month and year of birth All attributes tested from birth to weaning were impacted by the year of birth (P< 0.05). Most authors who have studied the effect of this factor have stated that it has a relatively significant effect on growth capacity, which can be explained by a variety of factors, including climate (temperature, rainfall, humidity, etc.), management practices, and the quality and quantity of feed available to the animals (Mohammadi et al., 2010). The birth period effect is significant and indicates an advantage for W10, W30, and W60 for animals born in October-November (start of the rainy season), with growth rates during the first month of around 170 g/d, compared with 150 g/d for animals born in the dry season (August). During this period, lambs are reared at the height of the grass season. These results are in line with those of Derquaoui (2003) and Rekik et al. (2008). This is in agreement with the results of Carrillo and Segura (1993). Higher weights and GMQ were found in lambs born in July and November, while the lowest weights and ADG were found in lambs born in August. In the same context, Ploumi and Emmanouilidis (1999) reported a highly significant effect of this factor on lamb birth weight. Most of the authors who studied the effect of this factor stated that it had a relatively marked effect on growth capacity. Correlation between growth parameters Phenotypic correlation analysis (Table 8) indicated that P30 had a positive and highly significant effect (P ≤ 0.01) on the majority of growth traits studied. This is in agreement with the results of Dixit et al. (2001). The highest phenotypic correlations between weights were observed between W10 and W30 (0.82) and between W30 and W60 (0.81). This analysis also revealed that the majority of phenotypic correlations between daily gains were positive and highly significant (P ≤ 0.01). It was also found that the phenotypic correlations between W30 and ADG0030 and between W60 and ADG3060 were, respectively, 0.98 and 0.84. On the other hand, an average correlation was recorded between ADG0030 and ADG3060 (0.37). Genetic parameters Héritability The low level of heritability explains the low level of additive genetic variance (Singh et al., 2006). Our results are in line with those of Yacob (2008) and Gizaw et al. (2007). W10 has a moderate heritability estimate (0.48 ± 0.03), suggesting that there is considerable scope for improvement of this trait through mass selection. The results obtained reveal relative stability in weight heritability coefficients at 10, 30, and 60 days (0.23 to 0.31), with a minimum at 10 days (0.23) and a slight tendency to increase with age. Heritability values for average daily gains are also of the same order of magnitude, with the highest heritability obtained for ADG0030 (h2 = 0.31 ± 0.064). Indeed, low to medium heritability estimates for early weight and growth are generally attributed to the importance of variation in maternal effects, particularly in milk production (Rao, 1997). Hermiz et al. (2009) have shown that the potential for genetic improvement depends largely on the genetic parameters of growth weight to which selection can be applied. Genetic correlation The genetic correlation coefficient for weight at 10 and 30 days is 0.75 and only reaches 0.42 for weight at 60 days. This result would seem to indicate a weak genetic link between prenatal and postnatal growth, which is confirmed by the low value of correlations with an average daily gain of 10–30 days (0.34) and an average daily gain of 30–60 days (0.14). In terms of genetic correlations, the most remarkable is the value of 0.82 between W30 and W60. This is because both are calculated from the same information and therefore deduced from each other. The practical consequence is that, under such conditions, P30 and ADG0030 express the same performance. Similarly, the genetic correlations of ADG0030 with the two weights W30 and W60 are almost identical, at 0.67 and 0.63. Genetic correlation estimates for W10 with other parameters (W60, ADG0030, and ADG3060) were of the order of 14–42%, providing evidence that W10 is not the right criterion for selecting lambs for higher adult gain. The genetic correlation estimates of 0.42 between W10 and W60 was lower than the estimate of 0.52 by Hanford et al. (2003) in the Targhee breed and in line with those found by Gowane et al. (2010a, 2010b), which were of the order of 0.45 and 0.41 in the Bharat Merino and Malpura breeds. Genetic correlations between W30 and W60, on the one hand, and W30 and ADG00-30 were 0.82 and 0.67, respectively. Similar results were observed by Swain et al. (2004) in the Bharat Merino breed and Gohil (2010) in the Marwari breed. Conclusion Finally, this study examined the growth performance of lambs from four Tunisian sheep breeds using extensive data collected from 134 flocks totaling 45780 lambs across 99 farms from 2011 to 2016. At typical ages, the findings revealed significant differences in weight and daily gains, with single-born lambs demonstrating higher weights and average daily gains than double-born lambs. The sex mode of birth also affected average daily gains, with single-born lambs growing faster. The genetic type factor had a significant impact on lamb growth, with the QFO breed performing best in terms of weight growth and average daily gain. Furthermore, the dam’s age played a role, with lambs from dams aged 3 to 4 years exhibiting higher average daily gains, while lambs from dams aged 5 years and older exhibited lower gains. The heritability coefficients for weights at various ages varied, with ADG30-60 having the lowest (0.16 0.021) and W10 having the highest (0.48 0.03). Estimates of genetic correlation revealed significant variability (14–42%) for W10 with other parameters (W60, ADG00-30, and ADG30-60). Overall, these findings add to our understanding of the factors that influence lamb growth in Tunisian sheep breeds, emphasizing the importance of genetic type, birth characteristics, and maternal age in shaping growth performance. The results obtained showed a significant difference in weight at typical ages and weight gains. The results obtained on the genetic parameters of sheep growth in Tunisia during the pre-weaning phase show the impact of maternal effects on the genetic variability of growth during the first month. In addition, the estimated values of the genetic correlation coefficients reveal the possibility of selection based on the shape of the growth curve, since weight at 10 days and growth during the first month, respectively, determine only 34% of the variability of weight at 60 days. According to the results obtained in this study, we can conclude that the growth performance achieved by lambs of the breeds studied is satisfactory. Declarations Declaration of competing interest We declare that we have no financial, personal, or academic competition with other people or organizations that can inappropriately influence our work. There are no possible conflicts of interest. Author contribution B.S.I, M.S.: conceptualization, data curation, investigation, methodology, validation, visualization, writing the original draft, and editing. N.M., H.M.: conceptualization, investigation, methodology, validation, visualization, and writing the original draft. H.M.: methodology, validation, visualization, and writing the original draft. N. M., BSI, M.S.: conceptualization, investigation, project administration, supervision, validation, visualization, writing the original draft, and editing. Funding This research did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors. 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Environmental and Genetic Parameters of Growth, Reproductive and Survival Performance of Afar and Blackhead Somali Sheep at Werer Agricultural Research Center. Fellowship Report, International Livestock Research Institute (ILRI) and Ethiopian Institute of Agricultural Research (EIAR), Ethiopia Zidane A., Niar A and Ababou A. 2015. Effect of some factors on lambs growth performances of the Algerian Ouled Djellal breed. Livestock Research for Rural Development 27 (7) Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3882594","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":269646715,"identity":"62c55254-6e6a-490b-8b89-080068c8dc1c","order_by":0,"name":"Ikram Ben Souf","email":"","orcid":"","institution":"INAT: Institut National Agronomique de Tunis","correspondingAuthor":false,"prefix":"","firstName":"Ikram","middleName":"Ben","lastName":"Souf","suffix":""},{"id":269646716,"identity":"130895cd-9cf9-4a31-8bb9-8d5952d92e9b","order_by":1,"name":"Mariem Saidani","email":"","orcid":"","institution":"École Supérieure d'Agriculture Mateur: Ecole Superieure d'Agriculture Mateur","correspondingAuthor":false,"prefix":"","firstName":"Mariem","middleName":"","lastName":"Saidani","suffix":""},{"id":269646717,"identity":"364ab387-c882-46f5-9289-674f7e4ff5df","order_by":2,"name":"Hajer M’Hamdi","email":"","orcid":"","institution":"Ministry of Agriculture","correspondingAuthor":false,"prefix":"","firstName":"Hajer","middleName":"","lastName":"M’Hamdi","suffix":""},{"id":269646718,"identity":"f2981a4e-1e9b-47c9-83a3-bf8443ed13cf","order_by":3,"name":"Naceur Mhamdi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4ElEQVRIiWNgGAWjYDADAyCWSKiAMBgqiNdyBqrlDNFaGNuI0GLOfvjhY949DNHm7KcTbzycd1jenL35AMPBPbi1WPakGRvzPGPI3dmTu9kicdthw509xxIYDjzD454DOWzSPAcYcjccyN0mAdTCuOFGjgHzhwN4tJx/w/4brOX8W6CWOYftQVoYDuDTciOHjRms5QbIlobDiURoeWYsOQes5e1mi4Rj6ckbzhxLOIBXy/nkhx/egB2Wu/Hmjxpr2w3Hmw8+wKcFCv7DGM1gkrAGJFBHiuJRMApGwSgYIQAAsr1hLeb2lqMAAAAASUVORK5CYII=","orcid":"","institution":"INAT: Institut National Agronomique de Tunis","correspondingAuthor":true,"prefix":"","firstName":"Naceur","middleName":"","lastName":"Mhamdi","suffix":""}],"badges":[],"createdAt":"2024-01-20 21:12:42","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3882594/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3882594/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":50446080,"identity":"0b081434-163d-4e3e-ba70-fdbeb9dee441","added_by":"auto","created_at":"2024-01-31 15:58:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":536549,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3882594/v1/7c74815b-626f-433b-9f22-8d60745cbfa3.pdf"}],"financialInterests":"","formattedTitle":"Environmental factors and genetic parameters of growth traits in Tunisian local sheep","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe Tunisian indigenous sheep (Ovis aries) population is critical to the country\u0026apos;s agriculture and economy, providing a significant supply of meat and wool while also playing an important role in conserving small ruminant genetic diversity. There has been a rising interest in increasing the production potential of these indigenous sheep breeds throughout the years. Understanding the variables that determine their growth features, particularly the connections between environmental and genetic elements, is critical for developing and executing effective breeding and management techniques to promote productivity and adaptability. Tunisian indigenous sheep breeds, which have adapted to a variety of environmental situations, are an important genetic resource. Understanding the complex interplay between genetic elements and environmental variables determining growth qualities in these native sheep breeds is critical for conservation and breeding initiatives. A complex combination of genetic and environmental variables influences sheep growth performance, including body weight, average daily increase, and other morphometric features. Nutrition, environment, and management techniques all interact with the genetic composition of the animals, influencing their growth and development. Several studies have emphasized the importance of environmental and genetic variables in defining development features in distinct sheep populations (Ben Sassi et al., 2019; Bouraoui et al., 2016). However, the particular interconnections of these elements and their influence on Tunisian native sheep breeds are still mostly unknown. Altitude, temperature, precipitation, and available pasture are known to have a substantial impact on sheep breeds\u0026apos; growth performance and adaptability (Ammar et al., 2018). Furthermore, genetic variation within and across Tunisian sheep breeds can have a significant influence on growth features and adaptation to local environments (Hajji et al., 2017). Numerous studies conducted across the world have proved the importance of environmental factors in affecting the development potential of sheep breeds (Notter, 2012; Salgado et al., 2015). Nutrition has been highlighted as a critical environmental element that determines development features because it directly affects the availability of vital nutrients and energy required for growth (NRC, 2007). Furthermore, environmental factors such as temperature, humidity, and the photoperiod can influence thermoregulation, feed intake, and nutrient utilization in sheep (Sawalha et al., 2017). Understanding the effect of environmental and genetic variables on growth parameters in Tunisian indigenous sheep is crucial for creating long-term breeding plans that take genetic diversity and environmental adaptability into account. This study may have implications not just for the preservation of indigenous genetic resources but also for increasing cattle output in Tunisian agricultural systems. When evaluating growth qualities in Tunisian indigenous sheep, genetic factors are equally important. Genetic selection algorithms may be adjusted to promote desired features, thereby increasing population genetic development (Guti\u0026eacute;rrez and Goyache, 2005). Understanding the heritability of these qualities, as well as the genetic links between individuals, might help breeders make better judgments about how to optimize growth potential while conserving genetic variety (Falconer and Mackay, 1996). The purpose of this study is to investigate the links between environmental influences and genetic characteristics, specifically how they impact growth features in Tunisian indigenous sheep. This study aims to give insights that might lead to the development of appropriate breeding and management techniques to improve the growth performance and resilience of these indigenous sheep breeds by performing a complete analysis.\u003c/p\u003e"},{"header":"Materials and methods ","content":"\u003cp\u003e\u003cstrong\u003eData\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe research was based on a data set comprised of growth checks performed on 134 herds between 2011 and 2016. The information gathered came from Sidi Thabet's Centre National d''Amélioration Génétique. Four breeds (BTN, BTR, QFO, and NT) were considered, totaling 45780 individuals. The farm code, flock number, animal number, sex and method of birth, month of birth, year of birth, mother number, mother's month and year of birth, weighing dates, and weights were all supplied for each lamb. Table 1 reflects the features of the data files examined.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e Characteristics of the data used\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePeriods\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e2011- 2016\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMothers\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19789\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eHerds\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e134\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFarms\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e99\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eData\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e45780\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eCalculating weights and weight gains at typical ages\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWeights at typical ages (WTA): 10 days (W10), 30 days (W30), and 60 days (W60) were estimated based on periodic weighings, and average daily gains between 10 and 30 days (ADG10-30) and between 30 and 60 days (ADG30-60) were calculated. Weights at standard ages (W10, W30, and W60) are determined using two methods based on the collected data: either the standard age is between two subsequent weighings, in which case linear interpolation is used. Extrapolation is used if the standard age does not fall between two weighings. The formula used in both circumstances is as follows:\u003c/p\u003e\n\u003cp\u003eW\u003csub\u003ex\u003c/sub\u003e= Wn\u003csub\u003e-1\u003c/sub\u003e- ((Wn-Wn-1) /(Dn-Dn-1)) (Dn-1-Dx)\u003c/p\u003e\n\u003cp\u003eWhere: WX is the weight after 10, 30, and 60 days. DX Date: 10, 30, or 60 days old. Pn and Wn-1 are the two weighings needed to determine W, while Dn and Dn-1 are the matching dates.\u003c/p\u003e\n\u003cp\u003eADG at normal ages is computed in grams as follows:\u003c/p\u003e\n\u003cp\u003eADG00-30 = (W30-WN) /30\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eADG30-60= (W60-W30) /30\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analyses\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Data were analyzed using SAS software version 9.4 (Statistical Analysis System, Release 9.4 2012; SAS Institute Inc., Cary, NC, USA). The mean effects of the factors of variation were estimated by the \"Least Squares\" method, using the LSmeans (Least Square Means) instruction. The model used to study the variability of the parameters considered (P10, P30, W60, ADG00-30, and ADG30-60) is as follows:\u003c/p\u003e\n\u003cp\u003eY\u003csub\u003eijkl\u003c/sub\u003e = µ + MBi + YBj+ AM\u003csub\u003ek\u003c/sub\u003e + SMl + Bm+ e\u003csub\u003eijklmn\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003eWhere:Y\u003csub\u003eijkl\u003c/sub\u003e is the performance of the nth lamb, µ is the overall mean. MBi is the fixed effect of the month of birth (i = 1-6), YBj is the fixed effect of the jth year of birth (j = 2011–2016), and AMk is the fixed effect of the kth age of the mother (k = 2–8, AM ≥ 9 years). SMl is the fixed effect of the lth sex mode of birth (l = 1-4). Bm is the fixed effect of the mth breed (m = 1-4), and Eijklmn is the random error relating to the e\u003csub\u003eijklmth\u003c/sub\u003e observation. Differences between means according to the factors studied were analyzed using the SNK (Student-Newman-Keuls) test.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Genetic parameters\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;An animal model with direct and maternal genetic influences is used to assess genetic components. The model comprises fixed characteristics (herd-year, sex-mode, mother’s age, and month of birth) as well as four random elements, the first two of which are associated (direct and maternal genetic impacts), and the final two of which are independent (effect of the permanent environment and residual effect). The Devirative-Free Restricted Maximum Likelihood (DF-REML) method was used to estimate covariance components, which was based on a simple animal model with direct genetic effects, including the fixed effects of herd year, month of birth, sex-mode of birth, and maternal age, and was run on VCE 4.2.5 software (Neumeier and Groeneveld, 1998).\u003c/p\u003e"},{"header":"Results ","content":"\u003cp\u003e\u003cstrong\u003eResults of analysis of variances\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe factors studied have significant effects on variation in weight at 10 days (W10), weight at typical ages (W30 and W60), and ADG00-30 and ADG30-60. Spring-born lambs were heavier at birth and had higher weights at typical ages (30 and 60 days) than winter, autumn, and summer-born lambs. As a result, they recorded higher growth rates (ADG 0\u0026ndash;30 and ADG 30\u0026ndash;60). Compared with females, males show superiority in terms of weight at 10 days (W10), weight at typical ages (W30 and W60), and ADG0-30 and ADG30-60. Litter size had an influence (P \u0026lt; 0.05) on W10, weights at typical ages (W30 and W60), and average daily gains (ADG00-30 and ADG30-60). The values calculated for single lambs are greater (P \u0026lt; 0.05) than for double and triplet lambs. ANOVA results showed that lambs born to the youngest dams had the lowest performance (P \u0026lt; 0.05) compared with lambs born to the oldest dams (\u0026ge; 5 and over) (Table 2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u0026nbsp;\u003c/strong\u003eVariation Factors of Growth Performance\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\" style=\"width: 74.7876%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTraits\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15.7258%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariation factors\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030 (g/d)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060 (g/d)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15.7258%;\"\u003e\n \u003cp\u003eYB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15.7258%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMB\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 15.7258%;\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eBTN\u003c/p\u003e\n \u003cp\u003eBTR\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eNTB\u003c/p\u003e\n \u003cp\u003eQFO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e7.74\u0026plusmn; 0,13\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e7.90\u0026plusmn; 0.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e11.54\u0026plusmn; 0.23\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e147.98\u0026plusmn; 4.28\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e126.62\u0026plusmn; 5.02\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.17 \u0026plusmn;0,14\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.39\u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e13.01\u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e169.71\u0026plusmn; 4.17\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e154.09\u0026plusmn; 4.89\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.43\u0026plusmn; 0.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.52 \u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e13.54 \u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e167.54 \u0026plusmn; 4.20\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e167.16 \u0026plusmn; 4.92\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.62\u0026plusmn; 0.15\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.41\u0026plusmn; 0.13\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e12.38 \u0026plusmn; 0.23\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e170.58\u0026plusmn; 4.39\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e132.08\u0026plusmn; 5.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 15.7258%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSM\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e9.25\u0026plusmn; 0.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e9.29 \u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e14.04 \u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e181.61 \u0026plusmn; 4.19\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e158.12\u0026plusmn; 4.92\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e7.70\u0026plusmn; 0,15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e7.63\u0026plusmn; 0,12\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e11.76 \u0026plusmn; 0.22\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e152.80 \u0026plusmn; 4.29\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e137.65 \u0026plusmn; 5.03\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.85 \u0026plusmn;0.15\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.86\u0026plusmn; 0.13\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e13.43\u0026plusmn; 0.22\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e173.84\u0026plusmn; 4.19\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e152.21\u0026plusmn; 4.91\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e7.33 \u0026plusmn;0.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e7.27\u0026plusmn; 0.11\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e11.23\u0026plusmn; 0.23\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e147.56\u0026plusmn; 4.27\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e131.97\u0026plusmn; 5.01\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 15.7258%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAM\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003cp\u003e\u0026gt;5\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e7.64 \u0026plusmn; 0.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e7.71\u0026plusmn; 0.12\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e11.79\u0026plusmn; 0.22\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e145.62\u0026plusmn; 4.27\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e135.84\u0026plusmn; 5.01\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.41 \u0026plusmn; 0.15\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.37\u0026plusmn; 0.13\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e12.76\u0026plusmn; 0.23\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e167.52\u0026plusmn; 4.25\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e146.09\u0026plusmn; 4.99\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.53 \u0026plusmn; 0.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.48\u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e12.97\u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e171.15\u0026plusmn; 4.24\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e149.65\u0026plusmn; 4.97\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.55 \u0026plusmn; 0.15\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11.1559%;\"\u003e\n \u003cp\u003e8.48\u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.7688%;\"\u003e\n \u003cp\u003e13.07\u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e170.98\u0026plusmn; 4.26\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.1129%;\"\u003e\n \u003cp\u003e152.97\u0026plusmn; 4.99\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026lowast;\u0026lowast; P \u0026lt; 0.01; \u0026lowast;\u0026lowast;\u0026lowast; P \u0026lt; 0.001; and ns (P \u0026gt; 0.05). Values with different letters (per column) are significantly different (P \u0026lt; 0.05). \u0026nbsp;AM=age of mother; YB=year of birth; MB=month of birth; B=breed; BTN=Black-headed Barbarine; BTR=red-head Barbararine; NTB=Noire de Thibar; QFO=Queue fine de l\u0026rsquo;Ouest; SM=sex mode of birth; WB=weight at birth; P30 =weight at 30 days; P60 =weight at 60 days; ADG00-30 =average daily gain between 0 and 30 d; ADG 30-60=average daily gain between 30 and 60 d.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffects of breed on growth performance\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003emean values (\u0026plusmn; SD) of the lambs\u0026apos; weights at typical ages and average daily gains are shown in Table 3. P10 ranged from 5.73\u0026plusmn;2.62 to 7.54\u0026plusmn;2.72kg. The highest value was for the QFO breed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u0026nbsp;\u003c/strong\u003eAverage performance by breed\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTraits\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030 (g/d)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060 (g/d)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBreed\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eBTN\u003c/p\u003e\n \u003cp\u003eBTR\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eNTB\u003c/p\u003e\n \u003cp\u003eQFO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.74\u0026plusmn; 0.13\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.90\u0026plusmn; 0.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11.54\u0026plusmn; 0.23\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e147.98\u0026plusmn; 4.28\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e126.62\u0026plusmn; 5.02\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.17 \u0026plusmn;0.14\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.9\u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.01\u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e169.71\u0026plusmn; 4.17\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e154.09\u0026plusmn; 4.89\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.43\u0026plusmn; 0.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.52 \u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.54 \u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e167.54 \u0026plusmn; 4.20\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e167.16 \u0026plusmn; 4.92\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.62\u0026plusmn; 0.15\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.41\u0026plusmn; 0.13\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12.38 \u0026plusmn; 0.23\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e170.58\u0026plusmn; 4.39\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e132.08\u0026plusmn; 5.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eBTN\u003c/strong\u003e, BTR, NTB, QFO; W10= weight at 10 days; W30 =weight at 30 days; W60 = weight at 60 days; ADG0030 = average daily gain between 0 and 30 days; ADG3060= average daily gain between 30 and 60 days\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffect of mode of birth on growth performance\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSingle-born lambs achieved higher weights and ADG than double-born lambs. These differences changed with age (Table 4). As an indication, single-born males had respective W10, W30, and W60j of 8.68\u0026plusmn;2.59, 8.98\u0026plusmn;2.28, and 13.63\u0026plusmn;3.95 kg, whereas double-born males recorded respective weights of 8.26\u0026plusmn;2.42, 8.3\u0026plusmn;1.93, \u0026nbsp; and 11.6\u0026plusmn;3.64 kg during the same typical ages.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4\u0026nbsp;\u003c/strong\u003eEffect of mode of birth on growth performance\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTraits\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG00-30 (g/j)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG30-60 (g/j)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSM\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.25\u0026plusmn; 0.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.29 \u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e14.04 \u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e181.61 \u0026plusmn; 4.19\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e158.12\u0026plusmn; 4.92\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.70\u0026plusmn; 0.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.63\u0026plusmn; 0.2\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11.76 \u0026plusmn; 0.22\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e152.80 \u0026plusmn; 4.29\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e137.65 \u0026plusmn; 5.03\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.85 \u0026plusmn;0.15\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.86\u0026plusmn; 0.13\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.43\u0026plusmn; 0.22\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e173.84\u0026plusmn; 4.19\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e152.21\u0026plusmn; 4.91\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.33 \u0026plusmn;0.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.27\u0026plusmn; 0.11\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11.23\u0026plusmn; 0.23\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e147.56\u0026plusmn; 4.27\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e131.97\u0026plusmn; 5.01\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eEffect of the mother\u0026rsquo;s age on growth performance\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eW10 and W30 were impacted by the age of the mother (P\u0026lt;0.001), as well as ADG00-30 and ADG30-60 (P\u0026lt;0.05) (table 5). Lambs born to two-year-old ewes weighed 0.77, 0.65, and 0.99 kg less than those born to three-year-old ewes and 0.8, 0.65, and 1.51 kg less than the averages for lambs born to five-year-old ewes. The ADG0030 and ADG3060 discrepancies are 22.678 and 10.81 g, respectively, to the detriment of lambs born to two-year-old moms. Lambs born to two-year-old mothers develop at a 14.07% slower rate than the herd average between 0 and 30 days.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 5\u003c/strong\u003e Growth performance according to maternal age\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTraits\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eEffects\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60 (kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030 (g/j)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060 (g/j)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAM\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003cp\u003e\u0026gt;5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.64 \u0026plusmn; 0.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.71\u0026plusmn; 0.12\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11.79\u0026plusmn; 0.22\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e145.62\u0026plusmn; 4.27\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e135.84\u0026plusmn; 5.01\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.41 \u0026plusmn; 0.15\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.37\u0026plusmn; 0.13\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12.76\u0026plusmn; 0.23\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e167.52\u0026plusmn; 4.25\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e146.09\u0026plusmn; 4.99\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.53 \u0026plusmn; 0.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.48\u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12.97\u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e171.15\u0026plusmn; 4.24\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e149.65\u0026plusmn; 4.97\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.55 \u0026plusmn; 0.15\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.48\u0026plusmn; 0.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.07\u0026plusmn; 0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e170.98\u0026plusmn; 4.26\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e152.97\u0026plusmn; 4.99\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003ePerformance by year of birth\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTable 6 displays the least squares of the influence of the lambing year. All attributes tested from birth to weaning were impacted by the year of birth (P\u0026lt; 0.05). Between 2011 and 2016, all growth parameters (W10, W30, W60, ADG 00-30, and ADG 30-60) increased by 7.67, 9.88, 11.88, 143.47, 133.41, 8.21, 9.43, 12.93, 161.99, and 149.95, respectively. Remembering the large interannual variation in rainfall.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 6\u003c/strong\u003e Growth performance by year of birth\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eYB\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eN Obs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMin\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMax\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2011\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e12690\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.67\u003cbr\u003e\u0026nbsp;9.88\u003cbr\u003e\u0026nbsp;11.88\u003cbr\u003e\u0026nbsp;143.47\u003cbr\u003e\u0026nbsp;133.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.46\u003cbr\u003e\u0026nbsp;2.11\u003cbr\u003e\u0026nbsp;3.92\u003cbr\u003e\u0026nbsp;68.34\u003cbr\u003e\u0026nbsp;91.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.21\u003cbr\u003e\u0026nbsp;4.8\u003cbr\u003e\u0026nbsp;9.7\u003cbr\u003e\u0026nbsp;-\u003cbr\u003e\u0026nbsp;-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003cbr\u003e\u0026nbsp;17\u003cbr\u003e\u0026nbsp;34\u003cbr\u003e\u0026nbsp;-\u003cbr\u003e\u0026nbsp;-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2012\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e2269\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.84\u003cbr\u003e\u0026nbsp;8.42\u003cbr\u003e\u0026nbsp;13.15\u003cbr\u003e\u0026nbsp;162.68\u003cbr\u003e\u0026nbsp;157.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.07\u003cbr\u003e\u0026nbsp;2.07\u003cbr\u003e\u0026nbsp;3.46\u003cbr\u003e\u0026nbsp;64.28\u003cbr\u003e\u0026nbsp;60.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2\u003cbr\u003e\u0026nbsp;3\u003cbr\u003e\u0026nbsp;3.1\u003cbr\u003e\u0026nbsp;-\u003cbr\u003e\u0026nbsp;-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003cbr\u003e\u0026nbsp;15.6\u003cbr\u003e\u0026nbsp;24.1\u003cbr\u003e\u0026nbsp;-\u003cbr\u003e\u0026nbsp;-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2013\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e8045\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.95\u003cbr\u003e\u0026nbsp;9.39\u003cbr\u003e\u0026nbsp;14.78\u003cbr\u003e\u0026nbsp;192.91\u003cbr\u003e\u0026nbsp;179.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.71\u003cbr\u003e\u0026nbsp;2.33\u003cbr\u003e\u0026nbsp;3.95\u003cbr\u003e\u0026nbsp;74.23\u003cbr\u003e\u0026nbsp;79.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003cbr\u003e\u0026nbsp;3\u003cbr\u003e\u0026nbsp;3.4\u003cbr\u003e\u0026nbsp;-\u003cbr\u003e\u0026nbsp;-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003cbr\u003e\u0026nbsp;20\u003cbr\u003e\u0026nbsp;32.7\u003cbr\u003e\u0026nbsp;233\u003cbr\u003e\u0026nbsp;217\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2014\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e10314\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.02\u003cbr\u003e\u0026nbsp;7.921\u003cbr\u003e\u0026nbsp;12.26\u003cbr\u003e\u0026nbsp;145.42\u003cbr\u003e\u0026nbsp;144.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.53\u003cbr\u003e\u0026nbsp;2.03\u003cbr\u003e\u0026nbsp;3.51\u003cbr\u003e\u0026nbsp;64.34\u003cbr\u003e\u0026nbsp;69.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003cbr\u003e\u0026nbsp;5.8\u003cbr\u003e\u0026nbsp;7.9\u003cbr\u003e\u0026nbsp;-\u003cbr\u003e\u0026nbsp;-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.1\u003cbr\u003e\u0026nbsp;17.8\u003cbr\u003e\u0026nbsp;33.3\u003cbr\u003e\u0026nbsp;268\u003cbr\u003e\u0026nbsp;221\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2015\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e4171\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.31\u003cbr\u003e\u0026nbsp;9.37\u003cbr\u003e\u0026nbsp;13.07\u003cbr\u003e\u0026nbsp;161.58\u003cbr\u003e\u0026nbsp;156.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.44\u003cbr\u003e\u0026nbsp;2.07\u003cbr\u003e\u0026nbsp;3.36\u003cbr\u003e\u0026nbsp;64.93\u003cbr\u003e\u0026nbsp;61.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.14\u003cbr\u003e\u0026nbsp;5.18\u003cbr\u003e\u0026nbsp;6.8\u003cbr\u003e\u0026nbsp;97.45\u003cbr\u003e\u0026nbsp;76.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.3\u003cbr\u003e\u0026nbsp;17,1\u003cbr\u003e\u0026nbsp;27,3\u003cbr\u003e\u0026nbsp;241\u003cbr\u003e\u0026nbsp;228\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2016\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e8291\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.21\u003cbr\u003e\u0026nbsp;9.43\u003cbr\u003e\u0026nbsp;12.93\u003cbr\u003e\u0026nbsp;161.99\u003cbr\u003e\u0026nbsp;149.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.46\u003cbr\u003e\u0026nbsp;2.34\u003cbr\u003e\u0026nbsp;3.71\u003cbr\u003e\u0026nbsp;75.91\u003cbr\u003e\u0026nbsp;81.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.21\u003cbr\u003e\u0026nbsp;6.8\u003cbr\u003e\u0026nbsp;9.8\u003cbr\u003e\u0026nbsp;-\u003cbr\u003e\u0026nbsp;-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.23\u003cbr\u003e\u0026nbsp;19.9\u003cbr\u003e\u0026nbsp;32.6\u003cbr\u003e\u0026nbsp;256\u003cbr\u003e\u0026nbsp;249\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eEffect of birth month on Performance\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnalysis of the effect of lambing month on lamb growth indicated that this factor was an important source of variation in typical age weights and average daily gains (table 7).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 7\u003c/strong\u003e Growth performance by month of birth\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMB\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eN Obs\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMeans\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMin\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMax\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e43\u003cbr\u003e\u0026nbsp;43\u003cbr\u003e\u0026nbsp;43\u003cbr\u003e\u0026nbsp;43\u003cbr\u003e\u0026nbsp;43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10.54\u003cbr\u003e\u0026nbsp;11.83\u003cbr\u003e\u0026nbsp;16.69\u003cbr\u003e\u0026nbsp;236.81\u003cbr\u003e\u0026nbsp;204.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.52\u003cbr\u003e\u0026nbsp;1.88\u003cbr\u003e\u0026nbsp;3\u003cbr\u003e\u0026nbsp;63.11\u003cbr\u003e\u0026nbsp;77.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7\u003cbr\u003e\u0026nbsp;5. 8\u003cbr\u003e\u0026nbsp;9.1\u003cbr\u003e\u0026nbsp;86\u003cbr\u003e\u0026nbsp;60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15\u003cbr\u003e\u0026nbsp;14.1\u003cbr\u003e\u0026nbsp;27.2\u003cbr\u003e\u0026nbsp;351\u003cbr\u003e\u0026nbsp;530\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3554\u003cbr\u003e\u0026nbsp;3554\u003cbr\u003e\u0026nbsp;3554\u003cbr\u003e\u0026nbsp;3554\u003cbr\u003e\u0026nbsp;3554\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.05\u003cbr\u003e\u0026nbsp;9.23\u003cbr\u003e\u0026nbsp;12.97\u003cbr\u003e\u0026nbsp;150.25\u003cbr\u003e\u0026nbsp;163.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.81\u003cbr\u003e\u0026nbsp;2.1\u003cbr\u003e\u0026nbsp;4.28\u003cbr\u003e\u0026nbsp;67.74\u003cbr\u003e\u0026nbsp;106,41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003cbr\u003e\u0026nbsp;2.8\u003cbr\u003e\u0026nbsp;2.8\u003cbr\u003e\u0026nbsp;0\u003cbr\u003e\u0026nbsp;0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20\u003cbr\u003e\u0026nbsp;19.9\u003cbr\u003e\u0026nbsp;33.2\u003cbr\u003e\u0026nbsp;556\u003cbr\u003e\u0026nbsp;849\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e21790\u003cbr\u003e\u0026nbsp;21790\u003cbr\u003e\u0026nbsp;21790\u003cbr\u003e\u0026nbsp;21790\u003cbr\u003e\u0026nbsp;21790\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.90\u003cbr\u003e\u0026nbsp;8\u003cbr\u003e\u0026nbsp;12.48\u003cbr\u003e\u0026nbsp;148.83\u003cbr\u003e\u0026nbsp;149.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.6\u003cbr\u003e\u0026nbsp;2.17\u003cbr\u003e\u0026nbsp;3.94\u003cbr\u003e\u0026nbsp;69.63\u003cbr\u003e\u0026nbsp;85.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003cbr\u003e\u0026nbsp;2.8\u003cbr\u003e\u0026nbsp;2.8\u003cbr\u003e\u0026nbsp;0\u003cbr\u003e\u0026nbsp;0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.3\u003cbr\u003e\u0026nbsp;20\u003cbr\u003e\u0026nbsp;34\u003cbr\u003e\u0026nbsp;533\u003cbr\u003e\u0026nbsp;836\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19097\u003cbr\u003e\u0026nbsp;19400\u003cbr\u003e\u0026nbsp;19400\u003cbr\u003e\u0026nbsp;19400\u003cbr\u003e\u0026nbsp;19400\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.18\u003cbr\u003e\u0026nbsp;8.71\u003cbr\u003e\u0026nbsp;13.22\u003cbr\u003e\u0026nbsp;170.211\u003cbr\u003e\u0026nbsp;150.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.32\u003cbr\u003e\u0026nbsp;2.24\u003cbr\u003e\u0026nbsp;3.63\u003cbr\u003e\u0026nbsp;72.19\u003cbr\u003e\u0026nbsp;68.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.1\u003cbr\u003e\u0026nbsp;2.8\u003cbr\u003e\u0026nbsp;3\u003cbr\u003e\u0026nbsp;0\u003cbr\u003e\u0026nbsp;0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20\u003cbr\u003e\u0026nbsp;19.2\u003cbr\u003e\u0026nbsp;28.2\u003cbr\u003e\u0026nbsp;506\u003cbr\u003e\u0026nbsp;594\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e11\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e965\u003cbr\u003e\u0026nbsp;984\u003cbr\u003e\u0026nbsp;984\u003cbr\u003e\u0026nbsp;984\u003cbr\u003e\u0026nbsp;984\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.32\u003cbr\u003e\u0026nbsp;8.75\u003cbr\u003e\u0026nbsp;12.68\u003cbr\u003e\u0026nbsp;170.87\u003cbr\u003e\u0026nbsp;131.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.7\u003cbr\u003e\u0026nbsp;2.53\u003cbr\u003e\u0026nbsp;3.46\u003cbr\u003e\u0026nbsp;82.67\u003cbr\u003e\u0026nbsp;56.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2\u003cbr\u003e\u0026nbsp;2.8\u003cbr\u003e\u0026nbsp;3.8\u003cbr\u003e\u0026nbsp;0\u003cbr\u003e\u0026nbsp;0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e18\u003cbr\u003e\u0026nbsp;18.6\u003cbr\u003e\u0026nbsp;26.6\u003cbr\u003e\u0026nbsp;500\u0026nbsp;\u003cbr\u003e\u0026nbsp;406\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e12\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e965\u003cbr\u003e\u0026nbsp;984\u003cbr\u003e\u0026nbsp;984\u003cbr\u003e\u0026nbsp;984\u003cbr\u003e\u0026nbsp;984\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eW10\u003cbr\u003e\u0026nbsp;W30\u003cbr\u003e\u0026nbsp;W60\u003cbr\u003e\u0026nbsp;ADG0030\u003cbr\u003e\u0026nbsp;ADG3060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.18\u003cbr\u003e\u0026nbsp;8.01\u003cbr\u003e\u0026nbsp;11.91\u003cbr\u003e\u0026nbsp;144.55\u003cbr\u003e\u0026nbsp;129.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.3\u003cbr\u003e\u0026nbsp;1.55\u003cbr\u003e\u0026nbsp;2.18\u003cbr\u003e\u0026nbsp;49.66\u003cbr\u003e\u0026nbsp;36.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.6\u003cbr\u003e\u0026nbsp;6\u003cbr\u003e\u0026nbsp;9.4\u003cbr\u003e\u0026nbsp;80\u003cbr\u003e\u0026nbsp;80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.8\u003cbr\u003e\u0026nbsp;10.8\u003cbr\u003e\u0026nbsp;15.6\u003cbr\u003e\u0026nbsp;238\u003cbr\u003e\u0026nbsp;207\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eCorrelation between growth parameters\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;All phenotypic correlations (Table 8). between body weights were positive and high (P \u0026le; 0.01)).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 8\u003c/strong\u003e: Phenotypic correlations of lamb growth traits\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.84\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eGenetic parameters\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eH\u0026eacute;ritability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGrowth performance heritability coefficients are presented in Table 9. Heritability estimates are low overall, ranging from 0.16 \u0026plusmn; 0.04 for ADG3060 to 0.48 \u0026plusmn; 0.03 for W10.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 9\u0026nbsp;\u003c/strong\u003eEstimates of covariance components and genetic parameters of different growth parameters\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026sigma;\u003csup\u003e2\u003c/sup\u003e\u003csub\u003ea\u003c/sub\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026sigma;\u003csup\u003e2\u003c/sup\u003e\u003csub\u003er\u003c/sub\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026sigma;\u003csup\u003e2\u003c/sup\u003e\u003csub\u003ep\u003c/sub\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eh\u003csup\u003e2\u003c/sup\u003e\u0026plusmn;SD\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBTN\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.48 \u0026plusmn; 0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.29 \u0026plusmn; 0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.29 \u0026plusmn; 0.048\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e169.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e480.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e650.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.26 \u0026plusmn; 0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e72.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e394.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e467.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.16 \u0026plusmn; 0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBTR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.30 \u0026plusmn; 0.079\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.29 \u0026plusmn; 0.091\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.29\u0026plusmn; 0.032\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e55.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e122.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e178.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.31 \u0026plusmn; 0.064\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e96.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e401.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e507.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.19 \u0026plusmn; 0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eQFO\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.23 \u0026plusmn; 0.052\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.27 \u0026plusmn; 0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.28 \u0026plusmn; 0.049\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e164.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e461.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e653.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.25 \u0026plusmn; 0.051\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e72.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e394.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e467.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.16\u0026plusmn; 0.021\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eNT\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.29\u0026plusmn; 0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.46\u0026plusmn; 0.031\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.68\u0026plusmn; 0.051\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e133.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e362.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e466.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.29\u0026plusmn; 0.021\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e55.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e122.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e178.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.31\u0026plusmn; 0.042\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026sigma;\u003csup\u003e2\u003c/sup\u003e\u003csub\u003ea\u003c/sub\u003e\u003c/strong\u003e, \u003cstrong\u003e\u0026sigma;\u003csup\u003e2\u003c/sup\u003e\u003csub\u003er\u003c/sub\u003e \u0026sigma;\u003csup\u003e2\u003c/sup\u003e\u003csub\u003ep\u003c/sub\u003e\u003c/strong\u003e, are additive genetic variance, residual variance, r\u0026eacute;siduelle et ph\u0026eacute;notypic variance, \u0026nbsp;\u003cstrong\u003eh\u003csup\u003e2\u003c/sup\u003e\u0026plusmn; SD=\u003c/strong\u003e heritability (\u0026plusmn; SD)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eGenetic correlation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGenetic correlations between weights are higher the closer the ages considered (Table 10). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 10\u003c/strong\u003e Genetic correlations of different growth parameters\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.28\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eW60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG0030\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eADG3060\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussions","content":"\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Variation factors of growth performance\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe similarity of results between the four seasons could be a form of adaptation to farming practices in the study region, where animals are kept in permanent stalls. They are always protected from the cold and heat of summer. Lambing season was a highly significant influencing factor (P\u0026lt;0.001) for all the growth parameters studied (weights at standard ages and corresponding ADGs, except ADG 70\u0026ndash;90). The effect of the season of birth is felt in the evolution of lamb weights since lambs born in spring have higher weights at standard ages than lambs born in other seasons. These results are in line with those of Rekik et al. (2008) and Derquaoui (2003), who found that ewe lambs born in summer were heavier (27 kg) than those born in winter (25 kg). Similarly, Chniter et al. (2011) and Rekik et al. (2008) showed that the season of birth has a significant effect on the growth of D\u0026apos;Man lambs.\u003c/p\u003e\n\u003cp\u003eIn the present study, the ewe\u0026rsquo;s age affected lamb weights and ADGs. The weights of lambs in the two-year-old group were lower (P \u0026lt; 0.001) than those in the 3 to 5+ age groups. Indeed, lamb weights increased with maternal age. In addition, the ADG of these lambs was significantly lower than that of lambs born to ewes aged 4 and 5 years. Our results are in line with those of Saghi et al. (2007) and Koncag\u0026uuml;l et al. (2013). In another study, the age of the ewe did not affect the lamb birth weight, but 2 and 7-year-old ewes tended to wean lighter lambs (Ray and Smith, 1966). However, some researchers were unable to find significant differences between ewe age groups in terms of lamb birth and weaning weights (Cemal et al., 2005; Aliyari et al., 2012; Aktas and Dogan, 2014). Indeed, less developed mammary glands and, consequently, insufficient milk production for their lambs may be at the root of the 2-year-old ewe\u0026apos;s lamb weight reduction. In line with several studies (Saghi et al., 2007; Koncag\u0026uuml;l et al., 2013; Aktas and Dogan, 2014), sex and mode of birth have a significant effect (P\u0026lt;0.001) on weights at typical ages and ADG of lambs, with an advantage for males and singletons over females and double lambs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffects of breed\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eP10 averaged 7.14 \u0026plusmn; 2.48 kg, with extreme values ranging from 1 to 10.3 kg, reflecting considerable variability. Weight at 30 days ranged from 8.58 \u0026plusmn;2.13 kg in BTN to 9.47 \u0026plusmn;2.2 kg in BTR. Weight at 60 days varied between 11.15\u0026plusmn;3.44 and 13.22\u0026plusmn;3.83 kg in the BTN and NTB breeds. Attenuated growth rates (ADG 0\u0026ndash;30 and ADG 30\u0026ndash;60) are equal to 153.13\u0026plusmn;71.89 and 140.34\u0026plusmn;77.21 g/d, respectively. Similarly, Ben Hamouda and Othmane (2011) reported significant digital productivity in terms of an average number of lambs (1,8) up to weaning. They reported that, on average, Barbarine lambs weigh 4.2\u0026plusmn;0.4; 5.37\u0026plusmn;1.32; 8.29\u0026plusmn;2.1; 14.04\u0026plusmn; 3.46; and 16.28\u0026plusmn; 3.83 kg at 0, 10, 30, 70, and 90 days. The results obtained in this study for weight at various ages of the Barbarine breeds are comparable to those obtained by other authors who have worked on the same race (Ben Gara, 2000; Rabhi, 2003; and Maaoui et al., 2016). Our results for the NTB and QFO breeds outperform those of Ben Salem et al. (2009), who found average weights for the same breeds at 10 and 30 days after lambing of 6 \u0026plusmn; 2 and 10 \u0026plusmn; 3 kg, respectively, and Rekik et al. (2005), who reported a W10d of 7.32.48 kg for the QFE breed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffect of mode of birth\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAccording to the results of the present study, we noted differences in favor of single lambs of the order of 0.42 kg at 10 days, 0.5 kg at 30 days, and 0.94 kg at 60 days. This is reflected in the weight gains corresponding to the different ages. However, Chniter et al. (2011) reported that the effect of birth mode on weight is most pronounced during the 10- to 30-day age period. The negative relationship between litter size and lamb growth is most often attributed to a reduced amount of milk available per lamb (Zidane et al., 2015). This is probably because for ewes with multiparous milk, although they produce more milk, the surplus quantity is insufficient to compensate for the increase in requirements. These results confirm those of Kerfal et al. (2005), who stated that birth weight decreases significantly with increasing litter size. This decrease in weight is also observed at later stages of growth through weaning. The slower growth in multiple-born lambs is the result of the mother\u0026apos;s dairy capacity during the first month. It diminishes with age thanks to compensatory growth in multiple-born lambs during the post-weaning period. This shows that multiple-born lambs compensate for stunted growth early in life.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffect of the mother\u0026rsquo;s age\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResults showed that lambs born to the youngest dams had the lowest performance compared with lambs born to the oldest dams (\u0026ge; 5 and over). Kuchtk and Dobe (2006) and Macit et al. (2001) observed similar findings. Lambs from four-year-old and two-year-old moms had the highest and lowest values, respectively. Matika et al. (2003) discovered a similar pattern, whereas Dixit et al. (2001) discovered that lambs from two-year-old moms had the highest ADGs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePerformance by month and year of birth\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll attributes tested from birth to weaning were impacted by the year of birth (P\u0026lt; 0.05). Most authors who have studied the effect of this factor have stated that it has a relatively significant effect on growth capacity, which can be explained by a variety of factors, including climate (temperature, rainfall, humidity, etc.), management practices, and the quality and quantity of feed available to the animals (Mohammadi et al., 2010).\u003c/p\u003e\n\u003cp\u003eThe birth period effect is significant and indicates an advantage for W10, W30, and W60 for animals born in October-November (start of the rainy season), with growth rates during the first month of around 170 g/d, compared with 150 g/d for animals born in the dry season (August). During this period, lambs are reared at the height of the grass season. These results are in line with those of Derquaoui (2003) and Rekik et al. (2008). This is in agreement with the results of Carrillo and Segura (1993). Higher weights and GMQ were found in lambs born in July and November, while the lowest weights and ADG were found in lambs born in August. In the same context, Ploumi and Emmanouilidis (1999) reported a highly significant effect of this factor on lamb birth weight. Most of the authors who studied the effect of this factor stated that it had a relatively marked effect on growth capacity.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrelation between growth parameters\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePhenotypic correlation analysis (Table 8) indicated that P30 had a positive and highly significant effect (P \u0026le; 0.01) on the majority of growth traits studied. This is in agreement with the results of Dixit et al. (2001). The highest phenotypic correlations between weights were observed between W10 and W30 (0.82) and between W30 and W60 (0.81). This analysis also revealed that the majority of phenotypic correlations between daily gains were positive and highly significant (P \u0026le; 0.01). It was also found that the phenotypic correlations between W30 and ADG0030 and between W60 and ADG3060 were, respectively, 0.98 and 0.84. On the other hand, an average correlation was recorded between ADG0030 and ADG3060 (0.37).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eGenetic parameters\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eH\u0026eacute;ritability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe low level of heritability explains the low level of additive genetic variance (Singh et al., 2006). Our results are in line with those of Yacob (2008) and Gizaw et al. (2007). W10 has a moderate heritability estimate (0.48 \u0026plusmn; 0.03), suggesting that there is considerable scope for improvement of this trait through mass selection. The results obtained reveal relative stability in weight heritability coefficients at 10, 30, and 60 days (0.23 to 0.31), with a minimum at 10 days (0.23) and a slight tendency to increase with age. Heritability values for average daily gains are also of the same order of magnitude, with the highest heritability obtained for ADG0030 (h2 = 0.31 \u0026plusmn; 0.064). Indeed, low to medium heritability estimates for early weight and growth are generally attributed to the importance of variation in maternal effects, particularly in milk production (Rao, 1997). Hermiz et al. (2009) have shown that the potential for genetic improvement depends largely on the genetic parameters of growth weight to which selection can be applied.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eGenetic correlation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe genetic correlation coefficient for weight at 10 and 30 days is 0.75 and only reaches 0.42 for weight at 60 days. This result would seem to indicate a weak genetic link between prenatal and postnatal growth, which is confirmed by the low value of correlations with an average daily gain of 10\u0026ndash;30 days (0.34) and an average daily gain of 30\u0026ndash;60 days (0.14). In terms of genetic correlations, the most remarkable is the value of 0.82 between W30 and W60. This is because both are calculated from the same information and therefore deduced from each other. The practical consequence is that, under such conditions, P30 and ADG0030 express the same performance. Similarly, the genetic correlations of ADG0030 with the two weights W30 and W60 are almost identical, at 0.67 and 0.63. Genetic correlation estimates for W10 with other parameters (W60, ADG0030, and ADG3060) were of the order of 14\u0026ndash;42%, providing evidence that W10 is not the right criterion for selecting lambs for higher adult gain. The genetic correlation estimates of 0.42 between W10 and W60 was lower than the estimate of 0.52 by Hanford et al. (2003) in the Targhee breed and in line with those found by Gowane et al. (2010a, 2010b), which were of the order of 0.45 and 0.41 in the Bharat Merino and Malpura breeds. Genetic correlations between W30 and W60, on the one hand, and W30 and ADG00-30 were 0.82 and 0.67, respectively. Similar results were observed by Swain et al. (2004) in the Bharat Merino breed and Gohil (2010) in the Marwari breed.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eFinally, this study examined the growth performance of lambs from four Tunisian sheep breeds using extensive data collected from 134 flocks totaling 45780 lambs across 99 farms from 2011 to 2016. At typical ages, the findings revealed significant differences in weight and daily gains, with single-born lambs demonstrating higher weights and average daily gains than double-born lambs. The sex mode of birth also affected average daily gains, with single-born lambs growing faster. The genetic type factor had a significant impact on lamb growth, with the QFO breed performing best in terms of weight growth and average daily gain. Furthermore, the dam\u0026rsquo;s age played a role, with lambs from dams aged 3 to 4 years exhibiting higher average daily gains, while lambs from dams aged 5 years and older exhibited lower gains. The heritability coefficients for weights at various ages varied, with ADG30-60 having the lowest (0.16 0.021) and W10 having the highest (0.48 0.03). Estimates of genetic correlation revealed significant variability (14\u0026ndash;42%) for W10 with other parameters (W60, ADG00-30, and ADG30-60). Overall, these findings add to our understanding of the factors that influence lamb growth in Tunisian sheep breeds, emphasizing the importance of genetic type, birth characteristics, and maternal age in shaping growth performance. The results obtained showed a significant difference in weight at typical ages and weight gains. The results obtained on the genetic parameters of sheep growth in Tunisia during the pre-weaning phase show the impact of maternal effects on the genetic variability of growth during the first month. In addition, the estimated values of the genetic correlation coefficients reveal the possibility of selection based on the shape of the growth curve, since weight at 10 days and growth during the first month, respectively, determine only 34% of the variability of weight at 60 days. According to the results obtained in this study, we can conclude that the growth performance achieved by lambs of the breeds studied is satisfactory.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDeclaration of competing interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe declare that we have no financial, personal, or academic competition with other people or organizations that can inappropriately influence our work. There are no possible conflicts of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eB.S.I, M.S.: conceptualization, data curation, investigation, methodology, validation, visualization, writing the original draft, and editing. N.M., H.M.: conceptualization, investigation, methodology, validation, visualization, and writing the original draft. H.M.: methodology, validation, visualization, and writing the original draft. N. M., BSI, M.S.: conceptualization, investigation, project administration, supervision, validation, visualization, writing the original draft, and editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003eThis research did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e The data sets generated during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u0026nbsp;\u003c/strong\u003eThe authors certify that there is no conflict of interest regarding the materials discussed in this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col start=\"1\" type=\"1\"\u003e\n\u003cli\u003eAktas, A. H. and Dogan, S., 2014. Effect of live weight and age of Akkara- ˘ man ewes at mating on multiple birth rate, growth traits, and survival rate of lambs, Turk. J. Vet. Anim. Sci., 38, 176-182.\u003c/li\u003e\n\u003cli\u003eAliyari, D., Moeini, M. M., Shahir,M. H., and Sirjani, M. A., 2012. Effect of BSC, live weight and age on reproductive performance of Afshari Ewes, Asian J. Anim. Vet. Adv., 7, 904-909. \u003c/li\u003e\n\u003cli\u003eAmmar, H., Landolsi, F., Ben Gara, A., \u0026amp; Rekik, B. (2018). Influence of altitude on body measurements and growth traits in two sheep breeds in Tunisia. Small Ruminant Research, 167, 33-38.\u003c/li\u003e\n\u003cli\u003eBen Gara A., 2000. D\u0026eacute;finition des objectifs de s\u0026eacute;lection des ovins de race Barbarine en Tunisie. Dans : Options M\u0026eacute;diterran\u0026eacute;ennes, S\u0026eacute;ries A, no. 43, pp. 111-116\u003c/li\u003e\n\u003cli\u003eBen Hamouda M., Othmane M.H. Contr\u0026ocirc;le de croissance des ovins allaitants en Tunisie : proposition d,un nouveau protocole officiel, simplifie et flexible. In: Khlij E. (ed.), Ben Hamouda M. (ed.), Gabi\u0026ntilde;a D. (Ed.). Mutations des syst\u0026egrave;mes d\u0026rsquo;\u0026rsquo;\u0026eacute;levage des ovins et perspectives de leur durabilit\u0026eacute;. Zaragoza : CIHEAM / IRESA / OEP, 2011. p. 133-143 (Options M\u0026eacute;diterran\u0026eacute;ennes : S\u0026eacute;rie A. S\u0026eacute;minaires M\u0026eacute;diterran\u0026eacute;ens ; n. 97).\u003c/li\u003e\n\u003cli\u003eBen Sassi, M., Ben Gara, A., Djemali, M., \u0026amp; Boly, H. (2019). Genetic parameter estimation and breeding value prediction for body weights in Tazegzawt sheep. Small Ruminant Research, 177,73-78.\u003c/li\u003e\n\u003cli\u003eBouraoui, R., Rekik, B., Djemali, M., \u0026amp; Boly, H. (2016). Environmental effects on growth traits of Barbarine lambs in Tunisian oasis. 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Genetic diversity of Tunisian sheep breeds using microsatellite markers. Small Ruminant Research, 146, 32-37.\u003c/li\u003e\n\u003cli\u003eFalconer, D. S., \u0026amp; Mackay, T. F. C. (1996). Introduction to Quantitative Genetics. Longman.\u003c/li\u003e\n\u003cli\u003eDerquaoui L 2003. Av\u0026egrave;nement de la pubert\u0026eacute; chez les races ovines D,man et Sardi et leurs produits de croisement. Rencontres de la Recherche sur les Ruminants 10 :147-148 http://www.journees3r.fr/IMG/pdf/reproduction_13_Derqaoui.pdf\u003c/li\u003e\n\u003cli\u003eDixit, S. P., Dhillon, J. S., Singh, G., 2001. Genetic and non\u0026ndash;genetic parameter estimates for growth traits of Bharat Merino lambs. Small Rumin. Res., 42: 101\u0026ndash;104\u003c/li\u003e\n\u003cli\u003eFalconer, D.S., 1989. Introduction to Quantitative Genetics. 3rd Edition, Longman, London.\u003c/li\u003e\n\u003cli\u003eGizaw, S., Lemma, S., Komen, H. and Van Arendonk, J.A., 2007. 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Livestock Research for Rural Development 27 (7)\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"genetic performances, sheep, growth, heritability","lastPublishedDoi":"10.21203/rs.3.rs-3882594/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3882594/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study aimed to evaluate the growth performance of lambs from four Tunisian sheep breeds. It involved 45780 lambs in 134 flocks from 99 farms. The zootechnical data (live weight, average daily gain) for the period 2011\u0026ndash;2016 were obtained from the C of Genetic Improvement of the Office of Livestock and Pastures in Sidi Thabet. The results obtained showed a significant difference in weight and daily gains at typical ages. Lambs from single births were heavier than lambs from double births (1.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14 and 1\u0026thinsp;\u0026plusmn;\u0026thinsp;0,01 kg). ADGs were influenced by the sex-mode of birth (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Single-born lambs showed higher ADGs, followed by twice-born lambs. The genetic type factor significantly influenced the growth of the lambs (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). However, it should be noted that performance (weight growth and average daily gain) was better at the QFO breed. The age of the dams showed higher ADGs in lambs from dams aged 3 to 4 years, while the lowest ADGs were recorded in lambs from dams aged 5 years and older. The heritability coefficients of weights at different ages were estimated at 0.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04 for ADG3060 and 0.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03 for W10. The lowest values were observed for the ADG3060 (0.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.021). The highest value is obtained for P10. Estimates of the genetic correlation for W10 with other parameters (W60, ADG0030, and ADG3060) were of the order of 14\u0026ndash;42% of the variability.\u003c/p\u003e","manuscriptTitle":"Environmental factors and genetic parameters of growth traits in Tunisian local sheep","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-30 12:04:34","doi":"10.21203/rs.3.rs-3882594/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f7a9f714-854d-4397-8d7b-c5222dd39bfd","owner":[],"postedDate":"January 30th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-01-31T15:50:34+00:00","versionOfRecord":[],"versionCreatedAt":"2024-01-30 12:04:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3882594","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3882594","identity":"rs-3882594","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}