Effects of Age at First Calving on Some Reproductive and Herd Parameters in Anatolian Buffaloes

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The dataset consisted of records from 641 breeding female buffaloes and their 2,256 calves born over the years in 89 farms between 2012 and 2022. Breeding female buffaloes were classified into three groups according to their age at first calving as ≤ 37.99 months (Group 1, n = 271), 38–49.99 months (Group 2, n = 228), or ≥ 50 months (Group 3, n = 142). Age at first calving differed statistically among Groups 1, 2, and 3 (34.09 ± 0.15, 43.73 ± 0.25, and 61.15 ± 0.84 months, respectively) (p < 0.001). RL was higher in Group 1 (58.79 ± 2.41) than in Group 3 (45.29 ± 1.87); PL was higher in Group 1 (61.03 ± 4.48) than in Groups 2 and 3 (50.72 ± 2.07 and 43.77 ± 1.87, respectively); and HL was higher in Group 3 (104.08 ± 2.01) than in Groups 1 and 2 (91.24 ± 2.39 and 94.68 ± 2.01, respectively) (p = 0.000). A strong positive correlation was found between age at first conception and AFC (r = 0.998), and between CI and SP (r = 0.997) (p < 0.001). Age at first calving (p < 0.001), SP (p < 0.001), NC (p < 0.001), and HL (p < 0.001) were identified as factors influencing reproductive life. In conclusion, late first calving (≥ 50 months) in Anatolian buffaloes reduces reproductive efficiency and leads to economic losses, while early first calving (≤ 37.99 months) increases herd productivity and the total number of calvings. Since age at first calving is critical for reproductive performance and lifelong reproductive activity, it is recommended to reduce age at first calving through improvements in nutrition, health, and genetic management. Anatolian buffalo age at first calving reproductive parameters herd life Figures Figure 1 Figure 2 Introduction Buffalo husbandry holds a significant position in the production of milk, meat, and draft power across many regions of the world and represents one of the fundamental components of traditional livestock systems throughout a wide geographical area extending from Southeast Asia to Anatolia (Chaudhari 2015; Uğurlu 2017 ; Perera 2011 ). The reproductive physiology of buffaloes is highly sensitive to environmental conditions and nutritional status (Seno et al. 2010 ; Tamboli et al. 2022 ; Parmar et al. 2019 ; Pawar et al. 2018 ; Penchev et al. 2014 ). Therefore, detailed investigation of the biological, managerial, and genetic factors shaping reproductive performance is of great importance, particularly in the development of sustainable productivity strategies for indigenous breeds (Yılmaz & Kara 2019 ; Yılmaz et al., 2024 ). Among these parameters, AFC stands out as a key indicator determining both lifelong productivity and total economic performance of the animal (Seno et al. 2010 ; Tamboli et al. 2022 ; Parmar et al. 2019 ; Pawar et al. 2018 ; Penchev et al. 2014 ). AFC plays a decisive role in the breeding value of an animal by influencing multidimensional functional traits such as breeding lifespan, lactation yield, calving number, calving interval, and service period (Verma et al. 2018 ). Numerous studies have reported that earlier AFC reduces production costs, extends reproductive life, and increases farm profitability, whereas delayed AFC increases maintenance and feeding costs, prolongs the non-productive period, and negatively affects both functional and economic efficiency (Dinç & Kutlu 2015 ; Thiruvenkadan et al. 2015 ; Lopez-Paredes et al. 2018; Tamboli et al. 2022 ). Conversely, some studies have reported limited benefits associated with early calving (Borghese 2005 ). In many buffalo breeds, performance traits such as service period, calving interval, dry period, lactation length, and milk yield play a decisive role in dairy production economics and may also interact with AFC (Chaudhry 1992 ). The present study was conducted to systematically evaluate key reproductive and functional longevity parameters - including AFC, CI, SP, CN, RL, PL, and HL- in Anatolian Buffaloes and aims to provide a scientific basis for the management of reproductive efficiency and the development of breeding programs in local buffalo populations. Material and methods Animal material The study was conducted at 89 enterprises in the Çorum province of Türkiye (located at a latitude of 40° 32′ 56″ and a longitude of 34° 57′ 12″, at an altitude of 750–850 m above sea level). Records were collected for all water buffalo born and calved on farms with 10–20 breeding female buffaloes over a 10-year period from 2012 to 2022 and, data of breeding female buffaloes first calved in this period were used to evaluate the reproductive parameters. In this context, breeding female buffaloes gave birth once were excluded, and the birth data of 2256 calves belonging to 641 breeding female buffaloes that had calved twice or more were used. The availability and accuracy of all the records relating to the date of birth, first calving, and death/culling of these 641 breeding female buffaloes were ascertained. Incomplete and abnormal animal records, which could be the result of acute or chronic disease, abortion, stillbirth, etc., were excluded, and only data from healthy animals with a body condition score of 3-3.5/5 were included. General feeding and management conditions were provided in all farms. Method Firstly, the following parameters were evaluated in 641 breeding female buffaloes in months: age at first calving (AFC), calving interval (CI), service period (SP), and calving number (CN). Secondly, the records of 306 breeding female buffaloes that were still in the herd at the end of the 10-year period were excluded from the calculation. The productive life (PL), reproductive life (RL), and herd life (HL) parameters of the remaining 335 breeding female buffaloes that died or were culled during the 10-year period were then evaluated in months. The data were categorised based on AFC into three groups: ≤37.99 (Group 1, n = 271), 38-49.99 (Group 2, n = 228), and ≥ 50 (Group 3, n = 142) months. Natural estrus was detected, and the breeding female buffaloes were inseminated by natural mating with the farm’s own buffalo bull. There was no estrus synchronisation or artificial insemination. All of the data were recorded and maintained in the Manda Yıldızı (Buffalo Star) programme, the official data system of the National Anatolian Buffalo Breeding in Farm Project (Tekerli, 2022 ). Statistical analysis Variables were first evaluated with respect to the assumptions required for parametric testing. Normality was assessed using the Kolmogorov–Smirnov test and homogeneity of variances was tested by Levene’s test. Descriptive statistics for the reproductive variables are presented in tabular form. Between-group comparisons of reproductive variables that satisfied parametric assumptions were performed using one-way analysis of variance (ANOVA) followed by Duncan’s multiple range test; variables that did not meet these assumptions were analyzed using the Kruskal–Wallis test followed by multiple Dunn’s post hoc comparisons. Spearman’s rank correlation coefficient was calculated to assess correlations among reproductive variables. Relationships between the dependent variables (RL, PL and HL - each modeled separately) and the reproductive parameters (independent variables) were examined using multiple linear regression analysis. A backward stepwise selection procedure was applied in the regression modeling. Regression assumptions were evaluated using the Durbin–Watson test for autocorrelation of residuals and tolerance and variance inflation factor (VIF) values to assess multicollinearity among independent variables. Statistical analyses were performed with IBM SPSS Statistics version 23.0. Statistical significance was set at p < 0.05. Results Reproductive data categorised according to AFC were presented in Table 1 and Fig. 1 . AFC was statistically different among the groups (p < 0.001). Table 1 Reproductive parameters in groups (Mean ± SEM). Parameters Grup 1 Grup 2 Grup 3 p n 271 228 142 AFC (month) 34.09 ± 0.15 c 43.73 ± 0.25 b 61.15 ± 0.84 a < 0.001 CI (month) 16.74 ± 0.37 16.21 ± 0.33 17.76 ± 0.57 0.246 SP (month) 6.38 ± 0.37 5.85 ± 0.33 7.40 ± 0.57 0.243 n 103 136 96 CN 4.06 ± 0.18 a 3.65 ± 0.14 a 3.06 ± 0.12 b 0.001 RL (month) 58.79 ± 2.41 a 52.26 ± 2.07 ab 45.29 ± 1.87 b 0.000 PL (month) 61.03 ± 4.48 a 50.72 ± 2.07 b 43.77 ± 1.87 b 0.000 HL (month) 91.24 ± 2.39 b 94.68 ± 2.01 b 104.08 ± 2.01 a 0.000 a,b,c : Different letters in the same row indicate statistical significance (p ≤ 0.001). AFC: age at first calving (month), CI: calving interval (month), SP: service period (month), CN: calving number, RL: reproductive life (month), PL: productive life (month), HL: herd life (month). The effect of season and year of birth of the breeding female buffaloes on reproductive parameters was presented in Table 2 and Fig. 2 . The birth of the breeding female buffaloes had a significant impact on all parameters. Table 2 The effect of season and year of birth of the breeding female buffaloes on reproductive parameters in groups (Mean ± SEM). Parameter AFC CI SP CN RL PL HL Overall 43.52 ± 0.46 16.78 ± 0.24 6.42 ± 0.24 3.61 ± 0.09 52.27 ± 1.27 51.90 ± 1.73 96.32 ± 1.27 Season Spring 44.25 ± 0.56 a 17.29 ± 0.30 a 6.93 ± 0.30 a 3.10 ± 0.09 b 45.79 ± 1.36 b 45.90 ± 2.15 b 90.88 ± 1.43 b Summer 41.43 ± 0.75 b 15.37 ± 0.25 b 5.01 ± 0.25 b 4.48 ± 0.13 b 64.04 ± 1.91 b 62.44 ± 1.91 b 106.01 ± 1.90 b Autumn 41.86 ± 1.73 ab 16.75 ± 0.35 ab 6.40 ± 0.40 ab 5.00 ± 1.50 ab 77.52 ± 2.10 ab 76.02 ± 2.09 ab 117.88 ± 2.90 ab Winter 38.89 ± 1.83 ab 13.16 ± 0.29 ab 2.80 ± 0.29 ab 8.00 ± 0.00 a 102.62 ± 2.02 a 101.12 ± 2.02 a 139.89 ± 3.00 a p 0.039 0.001 0.001 0.000 0.000 0.000 0.000 Year 2012–2013 54.58 ± 1.43 a 18.44 ± 0.84 a 8.09 ± 0.84 a 3.23 ± 0.22 b 48.01 ± 3.10 b 46.50 ± 3.10 bc 101.10 ± 3.21 a 2014–2015 46.26 ± 1.01 b 16.71 ± 0.39 ab 6.35 ± 0.39 ab 4.27 ± 0.16 a 62.91 ± 2.28 a 61.37 ± 2.28 a 106.28 ± 2.05 a 2016–2017 41.31 ± 0.74 c 16.96 ± 0.53 ab 6.60 ± 0.53 ab 3.55 ± 0.11 b 50.29 ± 1.44 b 52.58 ± 4.19 ab 90.22 ± 1.42 b 2018–2019 40.80 ± 0.86 c 15.61 ± 0.34 b 5.25 ± 0.34 b 2.43 ± 0.10 c 32.88 ± 1.58 c 31.38 ± 1.58 c 72.87 ± 1.76 c 2020–2021 38.45 ± 0.77 c 16.99 ± 0.68 ab 6.64 ± 0.68 ab - - - - p 0.000 0.020 0.020 0.000 0.000 0.000 0.000 a,b,c : Different letters in the same column indicate statistical significance within season and year factors. AFC: age at first calving (month), CI: calving interval (month), SP: service period (month), CN: calving number, RL: reproductive life (month), PL: productive life (month), HL: herd life (month) Spearman correlation coefficients of the relationships between reproductive parameters are presented in Table 3 . Multiple linear regression model results for RL, PL, and HL are shown in Tables 4 , 5 and 6 . As a result of the Durbin-Watson test evaluated for the autocorrelation assumption, it is determined that the residuals are not correlated with each other for all three models. As a result of the VIF values evaluated for the assumption of multicollinearity problem, the VIF values of CI variables in the RL and PL models were > 10, so they were not included in these models (Tables 3 and 4 ). Table 3 Relationships between reproductive parameters. Variables AFC (month) CI (month) SP (month) CN AFC (month) 1 0.006 0.006 -0.166 *** CI (month) 1 0.997 *** -0.189 *** SP (month) 1 -0.190 *** CN 1 Spearman correlation coefficient; ***: p < 0.001, AFC: age at first calving (month), CI: calving interval (month), SP: service period (month), CN: calving number Table 4 Multiple linear regression model result for RL. Variables β SE t p Constant -5.207 0.841 -6.191 < 0.001 AFC (month) -0.732 0.017 -43.469 < 0.001 SP (month) 0.402 0.029 13.740 < 0.001 CN 4.064 0.209 19.475 < 0.001 HL (month) 0.720 0.013 53.532 < 0.001 R 2 = 0.991 (F = 9594.79; p < 0.001), β: regression coefficient, SE: standard error, t: t statistics RL: reproductive life, AFC: age at first calving (month), SP: service period (month), CN: calving number, HL: herd life (month) Table 5 Multiple linear regression model result for PL. Variables β SE t p Constant 5.476 6.089 0.899 0.369 AFC (month) -0.862 0.140 -6.165 < 0.001 CN 3.548 1.426 2.489 0.013 HL (month) 0.758 0.096 7.907 < 0.001 R 2 = 0.561 (F = 141.73; p < 0.001), β: regression coefficient, SE: standard error, t: t statistics. PL: productive life, AFC: age at first calving (month), CN: calving number, HL: herd life (month) Table 6 Multiple linear regression model result for HL. Variables β SE t p Constant -25.360 3.131 -8.100 < 0.001 AFC (month) 0.968 0.043 22.273 < 0.001 CI (month) 1.471 0.088 16.733 < 0.001 CN 14.350 0.323 44.488 < 0.001 R 2 = 0.866 (F = 715.15; p < 0.001), β: regression coefficient, SE: standard error, t: t statistics. HL: herd life, AFC: age at first calving (month), CI: calving interval (month), CN: calving number It was found that AFC, SP, CN, and HL were effective on RL (p < 0.001). The variables given in Table 4 had an effect of 99% on RL and the model was significant (R2 = 0.991) (p < 0.001). The model created through regression analysis is shown in the equation below. RL = − 5.207 + (-0.732 × AFC) + (0.402 × SP) + (4.064 × CN) + (0.720 × HL) According to this model, a one-unit increase in the AFC decreased RL by 0.732 units, while a one-unit increase in SP, CN, and HL increased RL by 0.402, 4.064, and 0.720 units, respectively. AFC (p < 0.001), CN (p = 0.013), and HL (p < 0.001) were found to be effective in PL. The variables given in Table 5 had an effect of 56% on PL, and the model was statistically significant (R2 = 0.561) (p < 0.001). The model created using regression analysis is shown in the equation below. PL = 5.476 + (-0.862 × AFC) + (3.548 × CN) + (0.758 × HL) According to this model, a one-unit increase in AFC decreased PL by 0.862 units, while a one-unit increase in CN and HL increased it by 3.548 and 0.758 units, respectively. It was determined that AFC, CI, and CN were effective on HL (p < 0.001). The variables given in Table 6 had an effect of 86.6% on HL and the model was statistically significant (R2 = 0.866) (p < 0.001). The model created through regression analysis is shown in the equation below. HL=-25.360 + (0.968 × AFC) + (1.471 × CI) + (14.350 × CN) According to this model, a one-unit increase in AFC, CI, and CN resulted in increases of 0.968, 1.471, and 14.350 units in HL, respectively. Discussion This study comprehensively demonstrates the effects of age at first calving (AFC) on key reproductive performance indicators (calving interval [CI], service period [SP], number of calvings [CN]) and lifetime productivity parameters (reproductive lifespan [RL], productive life [PL], herd life [HL]) in Anatolian buffaloes, thereby contributing to the understanding of the multidimensional nature of reproductive biology in native buffalo populations. The findings indicate that AFC is a critical factor, particularly influencing the number of calvings, reproductive lifespan, and productive life. In contrast, short-term reproductive indicators such as CI and SP did not differ significantly among AFC groups. The effect of AFC observed in this study aligns with findings in other buffalo breeds, where delayed first calving negatively impacts maternal reproductive efficiency and lifetime reproductive activity (Seno et al., 2010 ; Tamboli et al., 2022 ; Parmar et al., 2019 ; Pawar et al., 2018 ; Penchev et al., 2014 ; Lopez-Paredes et al., 2018). For example, Perera ( 2011 ) reported in Egyptian buffaloes that animals calving at an earlier age exhibited shorter calving intervals and higher lifetime calving numbers, thereby enhancing herd productivity. Similarly, studies on Nili-Ravi and Murrah buffaloes have indicated that delayed first calving reduces reproductive performance (Rautela et al., 2024 ; Sreedharan & Nagarcenkar, 1987; Borghese ( 2005 ) also reported that early-maturing buffaloes not only achieve a higher number of calvings but also enjoy longer productive lifespans, conferring economic advantages. Considering that similar reproductive constraints are present in many buffalo breeds worldwide, early sexual maturity and first calving age are recommended to improve lifetime productivity and economic returns (Seno et al., 2010 ; Tamboli et al., 2022 ; Perera, 2011 ; Borghese, 2005 ; Parmar et al., 2019 ; Pawar et al., 2018 ; Lopez-Paredes et al., 2018). First calving ages vary considerably among different buffalo breeds due to genetic, environmental, and management factors (Rautela et al., 2024 ; Tamboli et al., 2022 ; Parmar et al., 2019 ; Pawar et al., 2018 ; Lopez-Paredes et al., 2018). In Turkey, the first calving age of Anatolian buffaloes ranges widely from 32.1 to 43.7 months, with means reported between 35.5 and 37.8 months (Şekerden, 2001 ; İzgi & Asker, 1988 ). This broad variation likely reflects inconsistencies in herd management, nutrition, or genetic diversity. However, a lower limit of 32.1 months indicates potential for early reproduction under optimal conditions. In Italian buffaloes raised in Turkey, first calving age is more consistent, averaging 37.64 ± 3.19 months (Özbaşer et al., 2022 ). Egyptian buffaloes show a similar age range (37.4–39.4 months), reflecting comparable puberty and reproductive timing under their respective production systems. Conversely, Nili-Ravi (47.06 months) and Murrah (41 months) breeds begin calving at significantly later ages (Rautela et al., 2024 ), which may result from breed-specific physiological development, management deficiencies, or adaptation challenges to non-native environments. This study demonstrates that Anatolian buffaloes with a first calving age ≥ 50 months exhibit marked reductions in reproductive performance. These animals show higher ages at first conception and significantly lower total calving numbers (p = 0.001). Delayed reproductive onset prolongs non-productive life and reduces the period during which the animal contributes to the herd, thereby decreasing production performance and economic returns (Seno et al., 2010 ; Tamboli et al., 2022 ). These results are consistent with literature emphasizing the advantages of early reproductive maturity in buffalo production (Borghese, 2005 ; Perera, 2011 ; Şekerden, 2001 ; Lopez-Paredes et al., 2018). Several studies have reported that delayed first calving in buffaloes is often associated with feeding and management conditions, with genetic potential also being a key determinant (Seno et al., 2010 ; Tamboli et al., 2022 ; Borghese, 2005 ; Perera, 2011 ; Şekerden, 2001 ; İzgi & Asker, 1988 ; Rautela et al., 2024 ; Lopez-Paredes et al., 2018). A strong positive correlation between SP and CI (r = 0.997) confirms the mutual determinacy of these parameters; longer SP inevitably extends CI, increasing herd management costs. Similar findings have been reported in Murrah and Nili-Ravi populations in Egypt and India (Rautela et al., 2024 ). The negative correlation between AFC and CN (r = − 0.166) indicates that early calving enables a higher lifetime number of calvings, supporting studies across multiple buffalo breeds that identify AFC as a key determinant of lifetime reproductive efficiency (Borghese, 2005 ; Perera, 2011 ). The regression models developed for RL, PL, and HL exhibited high explanatory power (R² = 0.991 for RL; R² = 0.866 for HL), confirming the strong statistical coherence among reproductive parameters. In the RL model, AFC exerted a negative effect, whereas SP, CN, and HL were positively associated. This indicates that RL is influenced not only by age but also by management practices, physiological stress, and reproductive intervals throughout the animal’s life. The negative effect of AFC on RL (β = − 0.732) validates the biological advantage of early calving. The positive effect of SP on RL is noteworthy, reflecting the natural mathematical consequence that longer-living animals experience more reproductive cycles. The strong positive effect of CN on RL (β = 4.064) underscores that lifetime reproductive rhythm is a primary determinant of RL. In the PL model, AFC, CN, and HL were significant predictors, demonstrating that productive life is shaped by both biological and environmental factors. The dominant negative effect of AFC (β = − 0.862) highlights reproductive onset as the most critical determinant of productive life. In the HL model, AFC had a positive effect (β = 0.968), suggesting that late-calving buffaloes are retained longer in the herd. This reflects a management strategy rather than a biological necessity, indicating that HL is more sensitive to managerial decisions than to reproductive parameters. Conclusion Buffaloes with a first calving age of 50 months or older exhibited marked reductions in reproductive efficiency, prolonged age at conception, and lower total numbers of calvings. These outcomes imply extended non-productive periods and increased economic losses. Early calving was found to optimize herd productivity by shortening calving intervals and increasing lifetime calving numbers. Consequently, maintaining AFC below approximately 38 months, alongside optimizing feeding and management practices to support the development of young females, appears critical for improving productivity in Anatolian buffaloes. This study fills an important gap by characterizing the unique dynamics of the native population. Overall, breeding and management strategies aimed at reducing AFC are likely to enhance both reproductive efficiency and economic sustainability in Anatolian buffaloes. Declarations Competing Interests: The authors have no relevant financial or non-financial interests to disclose. Ethics approval: Study Ethics Committee permission was granted by International Center For Livestock Research And Training, Animal Experiments Local Ethics Committee. Also this study was performed in line with the principles of the Declaration of Helsinki. Consent to participate: The study does not involve human participation. Funding: The author(s) reported that there is no funding associated with the work featured in this article. Author Contributions: The study conception and design were realized by [Mehmet Ali Yılmaz], [Engin Ünay], and [Muhammed İkbal Coşkun]. Material preparation, and data collection were performed by [Mehmet Ali Yılmaz], [Ramazan Sevgi], [Mesut Yıldırır], [Özden Sarıkaya], [Yusuf KAplan], and [Bülent Bülbül]. Analysis and first draft of the manuscript were written by [Ufuk Kaya], [Mesut Yıldırır], and [Alaeddin Okuroğlu]. Final versions of the manuscript controlled [Bülent Bülbül]. All authors read and approved the final manuscript. Acknowledgment: The data used in this study were provided by the Anatolian Buffalo Breeding Project, conducted under the Ministry of Agriculture and Forestry of the Republic of Turkey, General Directorate of Agricultural Research and Policies. We sincerely thank all project stakeholders for their contributions to the execution of this study. 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Correlation between extremes age at first calving with their productive and reproductive performances in Indian Murrah buffaloes (Bubalu sbubalis). Indian Journal of Animal Research, 52(10), 1506-1512. Yılmaz, A., Kara, M.A. (2019). Dünyada ve Türkiye’de Manda Yetiştiriciliğinin Durumu ve Geleceği. Turk J Agric Res, 2019, s.6(3): 356-363. Yılmaz, M.A., Kaymaz, M., Ergün, Y. (2024). Development, Quality, and Production Parameters of In Vitro Embryo in Anatolian Water Buffaloes. Tropical Animal Science Journal, 47(1). Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 09 Feb, 2026 Reviewers invited by journal 04 Feb, 2026 Editor assigned by journal 15 Jan, 2026 First submitted to journal 12 Jan, 2026 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. 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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-8578115","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":585656430,"identity":"81008466-cdbf-49e2-8c30-30f8db1cf612","order_by":0,"name":"Mehmet Ali Yılmaz","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABE0lEQVRIie3PsUoDMRjA8ZyBTCm3SUqHewIhLtLh8EVcvlBwOym4OKZLHRy6tij6CicHnXME6lLNWrnF7g51KTeomNiOd5kF8x9CSO7Hl0MoFPqTYakQ77vNU/3xncLvIQx9JHKE2Q2B7pScAyKOcD+xiyOU9yjRO4I85Oi6HGk6ZGfxRHFOqbmIkxuxeeMoiQ9VIzlZCqkpZ9lUKQDGqsvuuFMw+7Dj2S00E7UnspTKzqlEvujkjgCvWohZ78iDjkYS4MWRovaS1X5KvsAYKaUcmfunrNayvLPkcUmInTMQs3E27wNn7f9iBnrz/plm98Zs8Zc8FRP8XLzWV2kS95qJ64A2HLLWz11R7b0OhUKhf98PbBdoe0p9MLAAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-4497-2894","institution":"Republic of Turkey Ministry of Agriculture and Forestry: Turkiye Cumhuriyeti Tarim ve Orman Bakanligi","correspondingAuthor":true,"prefix":"","firstName":"Mehmet","middleName":"Ali","lastName":"Yılmaz","suffix":""},{"id":585656431,"identity":"aebda2cd-98c7-45e2-81a4-faad732d0302","order_by":1,"name":"Engin ÜNAY","email":"","orcid":"","institution":"TC Tarım ve Orman Bakanlığı: Turkiye Cumhuriyeti Tarim ve Orman Bakanligi","correspondingAuthor":false,"prefix":"","firstName":"Engin","middleName":"","lastName":"ÜNAY","suffix":""},{"id":585656432,"identity":"6262a7fc-8738-4491-8340-ada73980265e","order_by":2,"name":"Muhammed İkbal COŞKUN","email":"","orcid":"","institution":"TC Tarım ve Orman Bakanlığı: Turkiye Cumhuriyeti Tarim ve Orman Bakanligi","correspondingAuthor":false,"prefix":"","firstName":"Muhammed","middleName":"İkbal","lastName":"COŞKUN","suffix":""},{"id":585656433,"identity":"616de536-cacf-4f46-b728-66bdc4ffc3c6","order_by":3,"name":"Ramazan SEVGİ","email":"","orcid":"","institution":"TC Tarım ve Orman Bakanlığı: Turkiye Cumhuriyeti Tarim ve Orman Bakanligi","correspondingAuthor":false,"prefix":"","firstName":"Ramazan","middleName":"","lastName":"SEVGİ","suffix":""},{"id":585656434,"identity":"7d8e26d6-6e79-4794-ad1c-709600825e7f","order_by":4,"name":"Alaeddin OKUROĞLU","email":"","orcid":"","institution":"TC Tarım ve Orman Bakanlığı: Turkiye Cumhuriyeti Tarim ve Orman Bakanligi","correspondingAuthor":false,"prefix":"","firstName":"Alaeddin","middleName":"","lastName":"OKUROĞLU","suffix":""},{"id":585656435,"identity":"5567e3c9-5e2f-4b84-8ecd-24e99dadfe24","order_by":5,"name":"Mesut YILDIRIR","email":"","orcid":"","institution":"TC Tarım ve Orman Bakanlığı: Turkiye Cumhuriyeti Tarim ve Orman Bakanligi","correspondingAuthor":false,"prefix":"","firstName":"Mesut","middleName":"","lastName":"YILDIRIR","suffix":""},{"id":585656436,"identity":"d52ebe5b-3fb5-4f0a-bef7-ca6f368fd14f","order_by":6,"name":"Ufuk KAYA","email":"","orcid":"","institution":"Mustafa Kemal Universitesi: Hatay Mustafa Kemal Universitesi","correspondingAuthor":false,"prefix":"","firstName":"Ufuk","middleName":"","lastName":"KAYA","suffix":""},{"id":585656437,"identity":"952d2e08-8973-443f-9392-1a360579b156","order_by":7,"name":"Yusuf KAPLAN","email":"","orcid":"","institution":"TC Tarım ve Orman Bakanlığı: Turkiye Cumhuriyeti Tarim ve Orman Bakanligi","correspondingAuthor":false,"prefix":"","firstName":"Yusuf","middleName":"","lastName":"KAPLAN","suffix":""},{"id":585656438,"identity":"125345d0-0d89-4651-b085-100e16747d6a","order_by":8,"name":"Özden SARIKAYA","email":"","orcid":"","institution":"TC Tarım ve Orman Bakanlığı: Turkiye Cumhuriyeti Tarim ve Orman Bakanligi","correspondingAuthor":false,"prefix":"","firstName":"Özden","middleName":"","lastName":"SARIKAYA","suffix":""},{"id":585656439,"identity":"b8689735-3943-4d57-bcc1-7a60c5f3ca2c","order_by":9,"name":"Bülent BÜLBÜL","email":"","orcid":"","institution":"Dokuz Eylul University: Dokuz Eylul Universitesi","correspondingAuthor":false,"prefix":"","firstName":"Bülent","middleName":"","lastName":"BÜLBÜL","suffix":""}],"badges":[],"createdAt":"2026-01-12 06:49:04","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8578115/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8578115/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102194321,"identity":"38b07bcd-5222-46ae-875f-bafcd7a1ced6","added_by":"auto","created_at":"2026-02-09 09:43:27","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":257523,"visible":true,"origin":"","legend":"\u003cp\u003eReproductive parameters in groups (Mean±SEM). AFC: age at first calving (month), CI: calving interval (month), SP: service period (month), CN: calving number, RL: reproductive life (month), PL: productive life (month), HL: herd life (month).\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8578115/v1/7b08ca1f585cec2347d12f8a.jpeg"},{"id":102194308,"identity":"2ead5a94-5f6a-4a63-90d8-71e3862466d7","added_by":"auto","created_at":"2026-02-09 09:43:17","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":131152,"visible":true,"origin":"","legend":"\u003cp\u003eThe effect of season and year of birth of the breeding female buffaloes on reproductive parameters in groups (Mean±SEM). AFC: age at first calving (month), CI: calving interval (month), SP: service period (month), CN: calving number, RL: reproductive life (month), PL: productive life (month), HL: herd life (month).\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8578115/v1/39e4883f27935e21c9f8fa91.png"},{"id":102298709,"identity":"431af706-28d6-4fc8-ab4a-a3c8a6400302","added_by":"auto","created_at":"2026-02-10 10:58:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1242382,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8578115/v1/96bb659d-a843-4394-a236-ab440f04293f.pdf"}],"financialInterests":"","formattedTitle":"Effects of Age at First Calving on Some Reproductive and Herd Parameters in Anatolian Buffaloes","fulltext":[{"header":"Introduction","content":"\u003cp\u003eBuffalo husbandry holds a significant position in the production of milk, meat, and draft power across many regions of the world and represents one of the fundamental components of traditional livestock systems throughout a wide geographical area extending from Southeast Asia to Anatolia (Chaudhari 2015; Uğurlu \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Perera \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2011\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe reproductive physiology of buffaloes is highly sensitive to environmental conditions and nutritional status (Seno et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Tamboli et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Parmar et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pawar et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Penchev et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Therefore, detailed investigation of the biological, managerial, and genetic factors shaping reproductive performance is of great importance, particularly in the development of sustainable productivity strategies for indigenous breeds (Yılmaz \u0026amp; Kara \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Yılmaz et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Among these parameters, AFC stands out as a key indicator determining both lifelong productivity and total economic performance of the animal (Seno et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Tamboli et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Parmar et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pawar et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Penchev et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). AFC plays a decisive role in the breeding value of an animal by influencing multidimensional functional traits such as breeding lifespan, lactation yield, calving number, calving interval, and service period (Verma et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eNumerous studies have reported that earlier AFC reduces production costs, extends reproductive life, and increases farm profitability, whereas delayed AFC increases maintenance and feeding costs, prolongs the non-productive period, and negatively affects both functional and economic efficiency (Din\u0026ccedil; \u0026amp; Kutlu \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Thiruvenkadan et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Lopez-Paredes et al. 2018; Tamboli et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Conversely, some studies have reported limited benefits associated with early calving (Borghese \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). In many buffalo breeds, performance traits such as service period, calving interval, dry period, lactation length, and milk yield play a decisive role in dairy production economics and may also interact with AFC (Chaudhry \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1992\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe present study was conducted to systematically evaluate key reproductive and functional longevity parameters - including AFC, CI, SP, CN, RL, PL, and HL- in Anatolian Buffaloes and aims to provide a scientific basis for the management of reproductive efficiency and the development of breeding programs in local buffalo populations.\u003c/p\u003e"},{"header":"Material and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eAnimal material\u003c/h2\u003e \u003cp\u003eThe study was conducted at 89 enterprises in the \u0026Ccedil;orum province of T\u0026uuml;rkiye (located at a latitude of 40\u0026deg; 32\u0026prime; 56\u0026Prime; and a longitude of 34\u0026deg; 57\u0026prime; 12\u0026Prime;, at an altitude of 750\u0026ndash;850 m above sea level). Records were collected for all water buffalo born and calved on farms with 10\u0026ndash;20 breeding female buffaloes over a 10-year period from 2012 to 2022 and, data of breeding female buffaloes first calved in this period were used to evaluate the reproductive parameters. In this context, breeding female buffaloes gave birth once were excluded, and the birth data of 2256 calves belonging to 641 breeding female buffaloes that had calved twice or more were used. The availability and accuracy of all the records relating to the date of birth, first calving, and death/culling of these 641 breeding female buffaloes were ascertained. Incomplete and abnormal animal records, which could be the result of acute or chronic disease, abortion, stillbirth, etc., were excluded, and only data from healthy animals with a body condition score of 3-3.5/5 were included. General feeding and management conditions were provided in all farms.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eMethod\u003c/h3\u003e\n\u003cp\u003eFirstly, the following parameters were evaluated in 641 breeding female buffaloes in months: age at first calving (AFC), calving interval (CI), service period (SP), and calving number (CN). Secondly, the records of 306 breeding female buffaloes that were still in the herd at the end of the 10-year period were excluded from the calculation. The productive life (PL), reproductive life (RL), and herd life (HL) parameters of the remaining 335 breeding female buffaloes that died or were culled during the 10-year period were then evaluated in months. The data were categorised based on AFC into three groups: \u0026le;37.99 (Group 1, n\u0026thinsp;=\u0026thinsp;271), 38-49.99 (Group 2, n\u0026thinsp;=\u0026thinsp;228), and \u0026ge;\u0026thinsp;50 (Group 3, n\u0026thinsp;=\u0026thinsp;142) months. Natural estrus was detected, and the breeding female buffaloes were inseminated by natural mating with the farm\u0026rsquo;s own buffalo bull. There was no estrus synchronisation or artificial insemination. All of the data were recorded and maintained in the Manda Yıldızı (Buffalo Star) programme, the official data system of the National Anatolian Buffalo Breeding in Farm Project (Tekerli, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eVariables were first evaluated with respect to the assumptions required for parametric testing. Normality was assessed using the Kolmogorov\u0026ndash;Smirnov test and homogeneity of variances was tested by Levene\u0026rsquo;s test. Descriptive statistics for the reproductive variables are presented in tabular form. Between-group comparisons of reproductive variables that satisfied parametric assumptions were performed using one-way analysis of variance (ANOVA) followed by Duncan\u0026rsquo;s multiple range test; variables that did not meet these assumptions were analyzed using the Kruskal\u0026ndash;Wallis test followed by multiple Dunn\u0026rsquo;s post hoc comparisons. Spearman\u0026rsquo;s rank correlation coefficient was calculated to assess correlations among reproductive variables. Relationships between the dependent variables (RL, PL and HL - each modeled separately) and the reproductive parameters (independent variables) were examined using multiple linear regression analysis. A backward stepwise selection procedure was applied in the regression modeling. Regression assumptions were evaluated using the Durbin\u0026ndash;Watson test for autocorrelation of residuals and tolerance and variance inflation factor (VIF) values to assess multicollinearity among independent variables. Statistical analyses were performed with IBM SPSS Statistics version 23.0. Statistical significance was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eReproductive data categorised according to AFC were presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. AFC was statistically different among the groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eReproductive parameters in groups (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SEM).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGrup 1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGrup 2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGrup 3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003en\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e271\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e228\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e142\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAFC (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e43.73\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e61.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCI (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17.76\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.246\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSP (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.243\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003en\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e103\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e136\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCN\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.65\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eRL (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58.79\u0026thinsp;\u0026plusmn;\u0026thinsp;2.41\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e52.26\u0026thinsp;\u0026plusmn;\u0026thinsp;2.07\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePL (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e61.03\u0026thinsp;\u0026plusmn;\u0026thinsp;4.48\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50.72\u0026thinsp;\u0026plusmn;\u0026thinsp;2.07\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e43.77\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHL (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e91.24\u0026thinsp;\u0026plusmn;\u0026thinsp;2.39\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e94.68\u0026thinsp;\u0026plusmn;\u0026thinsp;2.01\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e104.08\u0026thinsp;\u0026plusmn;\u0026thinsp;2.01\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003csup\u003ea,b,c\u003c/sup\u003e: Different letters in the same row indicate statistical significance (p\u0026thinsp;\u0026le;\u0026thinsp;0.001). AFC: age at first calving (month), CI: calving interval (month), SP: service period (month), CN: calving number, RL: reproductive life (month), PL: productive life (month), HL: herd life (month).\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe effect of season and year of birth of the breeding female buffaloes on reproductive parameters was presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The birth of the breeding female buffaloes had a significant impact on all parameters.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe effect of season and year of birth of the breeding female buffaloes on reproductive parameters in groups (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SEM).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAFC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003ePL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eHL\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOverall\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e43.52\u0026thinsp;\u0026plusmn;\u0026thinsp;0.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.78\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e52.27\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e51.90\u0026thinsp;\u0026plusmn;\u0026thinsp;1.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e96.32\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"8\" nameend=\"c8\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSeason\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpring\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e44.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.56\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17.29\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e45.79\u0026thinsp;\u0026plusmn;\u0026thinsp;1.36\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e45.90\u0026thinsp;\u0026plusmn;\u0026thinsp;2.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e90.88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.43\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSummer\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41.43\u0026thinsp;\u0026plusmn;\u0026thinsp;0.75\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.01\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e64.04\u0026thinsp;\u0026plusmn;\u0026thinsp;1.91\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e62.44\u0026thinsp;\u0026plusmn;\u0026thinsp;1.91\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e106.01\u0026thinsp;\u0026plusmn;\u0026thinsp;1.90\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAutumn\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.73\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.75\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.40\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.00\u0026thinsp;\u0026plusmn;\u0026thinsp;1.50\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e77.52\u0026thinsp;\u0026plusmn;\u0026thinsp;2.10\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e76.02\u0026thinsp;\u0026plusmn;\u0026thinsp;2.09\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e117.88\u0026thinsp;\u0026plusmn;\u0026thinsp;2.90\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eWinter\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38.89\u0026thinsp;\u0026plusmn;\u0026thinsp;1.83\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.29\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.29\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e102.62\u0026thinsp;\u0026plusmn;\u0026thinsp;2.02\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e101.12\u0026thinsp;\u0026plusmn;\u0026thinsp;2.02\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e139.89\u0026thinsp;\u0026plusmn;\u0026thinsp;3.00\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ep\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0.039\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eYear\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e2012\u0026ndash;2013\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e54.58\u0026thinsp;\u0026plusmn;\u0026thinsp;1.43\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.44\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e48.01\u0026thinsp;\u0026plusmn;\u0026thinsp;3.10\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e46.50\u0026thinsp;\u0026plusmn;\u0026thinsp;3.10\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e101.10\u0026thinsp;\u0026plusmn;\u0026thinsp;3.21\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e2014\u0026ndash;2015\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46.26\u0026thinsp;\u0026plusmn;\u0026thinsp;1.01\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.27\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e62.91\u0026thinsp;\u0026plusmn;\u0026thinsp;2.28\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e61.37\u0026thinsp;\u0026plusmn;\u0026thinsp;2.28\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e106.28\u0026thinsp;\u0026plusmn;\u0026thinsp;2.05\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e2016\u0026ndash;2017\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41.31\u0026thinsp;\u0026plusmn;\u0026thinsp;0.74\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.96\u0026thinsp;\u0026plusmn;\u0026thinsp;0.53\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.60\u0026thinsp;\u0026plusmn;\u0026thinsp;0.53\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.55\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e50.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.44\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e52.58\u0026thinsp;\u0026plusmn;\u0026thinsp;4.19\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e90.22\u0026thinsp;\u0026plusmn;\u0026thinsp;1.42\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e2018\u0026ndash;2019\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.86\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.43\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e32.88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.58\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e31.38\u0026thinsp;\u0026plusmn;\u0026thinsp;1.58\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e72.87\u0026thinsp;\u0026plusmn;\u0026thinsp;1.76\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e2020\u0026ndash;2021\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38.45\u0026thinsp;\u0026plusmn;\u0026thinsp;0.77\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.99\u0026thinsp;\u0026plusmn;\u0026thinsp;0.68\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.68\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ep\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0.020\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.020\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003e\u003csup\u003ea,b,c\u003c/sup\u003e: Different letters in the same column indicate statistical significance within season and year factors. AFC: age at first calving (month), CI: calving interval (month), SP: service period (month), CN: calving number, RL: reproductive life (month), PL: productive life (month), HL: herd life (month)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSpearman correlation coefficients of the relationships between reproductive parameters are presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Multiple linear regression model results for RL, PL, and HL are shown in Tables\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, \u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and \u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. As a result of the Durbin-Watson test evaluated for the autocorrelation assumption, it is determined that the residuals are not correlated with each other for all three models. As a result of the VIF values evaluated for the assumption of multicollinearity problem, the VIF values of CI variables in the RL and PL models were \u0026gt;\u0026thinsp;10, so they were not included in these models (Tables\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelationships between reproductive parameters.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAFC (month)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCI (month)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSP (month)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCN\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAFC (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.006\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.006\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.166\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCI (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.997\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.189\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSP (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.190\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCN\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eSpearman correlation coefficient; ***: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, AFC: age at first calving (month), CI: calving interval (month), SP: service period (month), CN: calving number\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMultiple linear regression model result for RL.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eβ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003et\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eConstant\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-5.207\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.841\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-6.191\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAFC (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.732\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-43.469\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSP (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.402\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13.740\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCN\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4.064\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.209\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e19.475\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHL (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.720\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e53.532\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eR\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.991 (F\u0026thinsp;=\u0026thinsp;9594.79; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), β: regression coefficient, SE: standard error, t: t statistics RL: reproductive life, AFC: age at first calving (month), SP: service period (month), CN: calving number, HL: herd life (month)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMultiple linear regression model result for PL.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eβ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003et\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eConstant\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5.476\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6.089\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.899\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.369\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAFC (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.862\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.140\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-6.165\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCN\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.548\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.426\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.489\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.013\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHL (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.758\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.096\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7.907\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eR\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.561 (F\u0026thinsp;=\u0026thinsp;141.73; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), β: regression coefficient, SE: standard error, t: t statistics. PL: productive life, AFC: age at first calving (month), CN: calving number, HL: herd life (month)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMultiple linear regression model result for HL.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eβ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003et\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eConstant\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-25.360\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.131\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e-8.100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAFC (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.968\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.043\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22.273\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCI (month)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.471\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.088\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.733\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCN\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14.350\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.323\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e44.488\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eR\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.866 (F\u0026thinsp;=\u0026thinsp;715.15; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), β: regression coefficient, SE: standard error, t: t statistics. HL: herd life, AFC: age at first calving (month), CI: calving interval (month), CN: calving number\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIt was found that AFC, SP, CN, and HL were effective on RL (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The variables given in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e had an effect of 99% on RL and the model was significant (R2\u0026thinsp;=\u0026thinsp;0.991) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The model created through regression analysis is shown in the equation below.\u003c/p\u003e \u003cp\u003eRL\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;5.207 + (-0.732 \u0026times; AFC) + (0.402 \u0026times; SP) + (4.064 \u0026times; CN) + (0.720 \u0026times; HL)\u003c/p\u003e \u003cp\u003eAccording to this model, a one-unit increase in the AFC decreased RL by 0.732 units, while a one-unit increase in SP, CN, and HL increased RL by 0.402, 4.064, and 0.720 units, respectively.\u003c/p\u003e \u003cp\u003eAFC (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), CN (p\u0026thinsp;=\u0026thinsp;0.013), and HL (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) were found to be effective in PL. The variables given in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e had an effect of 56% on PL, and the model was statistically significant (R2\u0026thinsp;=\u0026thinsp;0.561) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The model created using regression analysis is shown in the equation below.\u003c/p\u003e\n\u003ch3\u003ePL = 5.476 + (-0.862 × AFC) + (3.548 × CN) + (0.758 × HL)\u003c/h3\u003e\n\u003cp\u003eAccording to this model, a one-unit increase in AFC decreased PL by 0.862 units, while a one-unit increase in CN and HL increased it by 3.548 and 0.758 units, respectively.\u003c/p\u003e \u003cp\u003eIt was determined that AFC, CI, and CN were effective on HL (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The variables given in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e had an effect of 86.6% on HL and the model was statistically significant (R2\u0026thinsp;=\u0026thinsp;0.866) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The model created through regression analysis is shown in the equation below.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eHL=-25.360 + (0.968 \u0026times; AFC) + (1.471 \u0026times; CI) + (14.350 \u0026times; CN)\u003c/h2\u003e \u003cp\u003eAccording to this model, a one-unit increase in AFC, CI, and CN resulted in increases of 0.968, 1.471, and 14.350 units in HL, respectively.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study comprehensively demonstrates the effects of age at first calving (AFC) on key reproductive performance indicators (calving interval [CI], service period [SP], number of calvings [CN]) and lifetime productivity parameters (reproductive lifespan [RL], productive life [PL], herd life [HL]) in Anatolian buffaloes, thereby contributing to the understanding of the multidimensional nature of reproductive biology in native buffalo populations. The findings indicate that AFC is a critical factor, particularly influencing the number of calvings, reproductive lifespan, and productive life. In contrast, short-term reproductive indicators such as CI and SP did not differ significantly among AFC groups.\u003c/p\u003e \u003cp\u003eThe effect of AFC observed in this study aligns with findings in other buffalo breeds, where delayed first calving negatively impacts maternal reproductive efficiency and lifetime reproductive activity (Seno et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Tamboli et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Parmar et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pawar et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Penchev et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Lopez-Paredes et al., 2018). For example, Perera (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) reported in Egyptian buffaloes that animals calving at an earlier age exhibited shorter calving intervals and higher lifetime calving numbers, thereby enhancing herd productivity. Similarly, studies on Nili-Ravi and Murrah buffaloes have indicated that delayed first calving reduces reproductive performance (Rautela et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Sreedharan \u0026amp; Nagarcenkar, 1987; Borghese (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e) also reported that early-maturing buffaloes not only achieve a higher number of calvings but also enjoy longer productive lifespans, conferring economic advantages. Considering that similar reproductive constraints are present in many buffalo breeds worldwide, early sexual maturity and first calving age are recommended to improve lifetime productivity and economic returns (Seno et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Tamboli et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Perera, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Borghese, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Parmar et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pawar et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Lopez-Paredes et al., 2018).\u003c/p\u003e \u003cp\u003eFirst calving ages vary considerably among different buffalo breeds due to genetic, environmental, and management factors (Rautela et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Tamboli et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Parmar et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pawar et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Lopez-Paredes et al., 2018). In Turkey, the first calving age of Anatolian buffaloes ranges widely from 32.1 to 43.7 months, with means reported between 35.5 and 37.8 months (Şekerden, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; İzgi \u0026amp; Asker, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1988\u003c/span\u003e). This broad variation likely reflects inconsistencies in herd management, nutrition, or genetic diversity. However, a lower limit of 32.1 months indicates potential for early reproduction under optimal conditions. In Italian buffaloes raised in Turkey, first calving age is more consistent, averaging 37.64\u0026thinsp;\u0026plusmn;\u0026thinsp;3.19 months (\u0026Ouml;zbaşer et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Egyptian buffaloes show a similar age range (37.4\u0026ndash;39.4 months), reflecting comparable puberty and reproductive timing under their respective production systems. Conversely, Nili-Ravi (47.06 months) and Murrah (41 months) breeds begin calving at significantly later ages (Rautela et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), which may result from breed-specific physiological development, management deficiencies, or adaptation challenges to non-native environments.\u003c/p\u003e \u003cp\u003eThis study demonstrates that Anatolian buffaloes with a first calving age\u0026thinsp;\u0026ge;\u0026thinsp;50 months exhibit marked reductions in reproductive performance. These animals show higher ages at first conception and significantly lower total calving numbers (p\u0026thinsp;=\u0026thinsp;0.001). Delayed reproductive onset prolongs non-productive life and reduces the period during which the animal contributes to the herd, thereby decreasing production performance and economic returns (Seno et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Tamboli et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). These results are consistent with literature emphasizing the advantages of early reproductive maturity in buffalo production (Borghese, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Perera, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Şekerden, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Lopez-Paredes et al., 2018). Several studies have reported that delayed first calving in buffaloes is often associated with feeding and management conditions, with genetic potential also being a key determinant (Seno et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Tamboli et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Borghese, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Perera, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Şekerden, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; İzgi \u0026amp; Asker, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1988\u003c/span\u003e; Rautela et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Lopez-Paredes et al., 2018).\u003c/p\u003e \u003cp\u003eA strong positive correlation between SP and CI (r\u0026thinsp;=\u0026thinsp;0.997) confirms the mutual determinacy of these parameters; longer SP inevitably extends CI, increasing herd management costs. Similar findings have been reported in Murrah and Nili-Ravi populations in Egypt and India (Rautela et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). The negative correlation between AFC and CN (r = \u0026minus;\u0026thinsp;0.166) indicates that early calving enables a higher lifetime number of calvings, supporting studies across multiple buffalo breeds that identify AFC as a key determinant of lifetime reproductive efficiency (Borghese, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Perera, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2011\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe regression models developed for RL, PL, and HL exhibited high explanatory power (R\u0026sup2; = 0.991 for RL; R\u0026sup2; = 0.866 for HL), confirming the strong statistical coherence among reproductive parameters. In the RL model, AFC exerted a negative effect, whereas SP, CN, and HL were positively associated. This indicates that RL is influenced not only by age but also by management practices, physiological stress, and reproductive intervals throughout the animal\u0026rsquo;s life. The negative effect of AFC on RL (β = \u0026minus;\u0026thinsp;0.732) validates the biological advantage of early calving. The positive effect of SP on RL is noteworthy, reflecting the natural mathematical consequence that longer-living animals experience more reproductive cycles. The strong positive effect of CN on RL (β\u0026thinsp;=\u0026thinsp;4.064) underscores that lifetime reproductive rhythm is a primary determinant of RL.\u003c/p\u003e \u003cp\u003eIn the PL model, AFC, CN, and HL were significant predictors, demonstrating that productive life is shaped by both biological and environmental factors. The dominant negative effect of AFC (β = \u0026minus;\u0026thinsp;0.862) highlights reproductive onset as the most critical determinant of productive life. In the HL model, AFC had a positive effect (β\u0026thinsp;=\u0026thinsp;0.968), suggesting that late-calving buffaloes are retained longer in the herd. This reflects a management strategy rather than a biological necessity, indicating that HL is more sensitive to managerial decisions than to reproductive parameters.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eBuffaloes with a first calving age of 50 months or older exhibited marked reductions in reproductive efficiency, prolonged age at conception, and lower total numbers of calvings. These outcomes imply extended non-productive periods and increased economic losses. Early calving was found to optimize herd productivity by shortening calving intervals and increasing lifetime calving numbers. Consequently, maintaining AFC below approximately 38 months, alongside optimizing feeding and management practices to support the development of young females, appears critical for improving productivity in Anatolian buffaloes. This study fills an important gap by characterizing the unique dynamics of the native population. Overall, breeding and management strategies aimed at reducing AFC are likely to enhance both reproductive efficiency and economic sustainability in Anatolian buffaloes.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting Interests:\u003c/h2\u003e \u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eEthics approval:\u003c/h2\u003e \u003cp\u003e Study Ethics Committee permission was granted by International Center For Livestock Research And Training, Animal Experiments Local Ethics Committee. Also this study was performed in line with the principles of the Declaration of Helsinki.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent to participate:\u003c/strong\u003e \u003cp\u003eThe study does not involve human participation.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eThe author(s) reported that there is no funding associated with the work featured in this article.\u003c/p\u003e\u003ch2\u003eAuthor Contributions:\u003c/h2\u003e \u003cp\u003eThe study conception and design were realized by [Mehmet Ali Yılmaz], [Engin \u0026Uuml;nay], and [Muhammed İkbal Coşkun]. Material preparation, and data collection were performed by [Mehmet Ali Yılmaz], [Ramazan Sevgi], [Mesut Yıldırır], [\u0026Ouml;zden Sarıkaya], [Yusuf KAplan], and [B\u0026uuml;lent B\u0026uuml;lb\u0026uuml;l]. Analysis and first draft of the manuscript were written by [Ufuk Kaya], [Mesut Yıldırır], and [Alaeddin Okuroğlu]. Final versions of the manuscript controlled [B\u0026uuml;lent B\u0026uuml;lb\u0026uuml;l]. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgment:\u003c/h2\u003e \u003cp\u003eThe data used in this study were provided by the Anatolian Buffalo Breeding Project, conducted under the Ministry of Agriculture and Forestry of the Republic of Turkey, General Directorate of Agricultural Research and Policies. We sincerely thank all project stakeholders for their contributions to the execution of this study.\u003c/p\u003e\u003ch2\u003eData availability statement:\u003c/h2\u003e \u003cp\u003eThe data presented in this study are available on reasonable request from the corresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003cp\u003eBorghese, A. (2005). Buffalo production and research. Rome: Food and Agriculture Organization of the United Nations (FAO).\u003c/p\u003e\n\u003cp\u003eChaudhry, M.A. (1992). Factors affecting the lactation length and milk yield in Nili-Ravi buffaloes. Asian-Australasian journal of animal sciences, 5(2), 375-382.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDin\u0026ccedil;, D.A., \u0026amp; Kutlu, M. (2015). S\u0026uuml;t ineklerinde reprod\u0026uuml;ktif performans parametreleri. Turkiye Klinikleri Veterinary Sciences-Obstetrics and Gynecology-Special Topics, 1(1), 17-31.\u003c/p\u003e\n\u003cp\u003eEl-Awady, H.G., Ibrahim, A.F., \u0026amp; El-Naser, I.A.M.A. (2021). The effect of age at first calving on productive life and lifetime profit in lactating Egyptian buffaloes. Buffalo Bulletin, 40(1), 71-85.\u003c/p\u003e\n\u003cp\u003eİzgi, T., \u0026amp; Asker, M. (1988). Anadolu mandalarının verim \u0026ouml;zellikleri \u0026uuml;zerine araştırmalar. Atat\u0026uuml;rk \u0026Uuml;niversitesi Ziraat Fak\u0026uuml;ltesi Dergisi, 19(2), 123\u0026ndash;132.\u003c/p\u003e\n\u003cp\u003e\u0026Ouml;zbaşer, E., \u0026Ouml;zdemir, M., \u0026amp; Yıldız, A. (2022). Reproductive traits and economic lifespan in Italian buffaloes. Journal of Animal Science, 100(4), 1234\u0026ndash;1242.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eParmar, G. A., Gupta, J. P., Chaudhari, J. D., Pandey, D. P., Prajapati, B. M., \u0026amp; Sathwara, R. N. (2019). Study of genetic and non-genetic factors affecting age at first calving and wet average in Mehsana buffaloes. Buffalo Bulletin, 38(1), 11\u0026ndash;17.\u003c/p\u003e\n\u003cp\u003ePawar, V. D., Dangar, N. S., Ramani, U. V., Pandya, G. M., Kharadi, V. B., \u0026amp; Brahmkshtri, B. P. (2018). Non-genetic factors affecting age at first calving in Surti buffaloes. International Journal of Livestock Research, 8(1), 55\u0026ndash;60.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePenchev, P., Dhaka, Y., \u0026amp; Yadav, K. (2014). Effect of season of birth on season of calving and age at first calving in buffalo heifers. Bulgarian Journal of Agricultural Science, 20(2), 447\u0026ndash;451.\u003c/p\u003e\n\u003cp\u003ePerera, B.M.A.O. (2011). Reproductive cycles of buffalo. Animal Reproduction Science, 124(3\u0026ndash;4), 194\u0026ndash;199.\u003c/p\u003e\n\u003cp\u003eRautela, R., Kumar, S., Sharma, R.K., Phulia, S.K., Kumar, R., Singh, M., Katiyar, R., Bharadwaj, A., \u0026amp; Datta, T. K. (2024). Impact of age at first calving on fertility and production performance in Murrah buffalo. Reproduction in Domestic Animals, 59(7), e14691.\u003c/p\u003e\n\u003cp\u003eSeno, L.O., Aspilcueta-Borquis, R.R., Tonhati, H., \u0026amp; Albuquerque, L. G. (2010). Genetic parameters for milk yield, age at first calving and interval between first and second calving in milk Murrah buffaloes. Livestock Research for Rural Development, 22(2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eŞekerden, \u0026Ouml;. (2001). Mandaların yetiştirme \u0026ouml;zellikleri ve verim performansları. \u0026Ccedil;ukurova \u0026Uuml;niversitesi Ziraat Fak\u0026uuml;ltesi Dergisi, 16(3), 47\u0026ndash;56.\u003c/p\u003e\n\u003cp\u003eTamboli P, Bharadwaj A, Chaurasiya AK, Jan MH, Kumar S and Khanna S (2023) Influence of non-genetic factors on first lactation and lifetime performance traits in Nili-Ravi buffaloes. Front. Anim. Sci. 4:1082943.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTamboli, P., Bharadwaj, A., Chaurasiya, A., Bangar, Y. C., \u0026amp; Jerome, A. (2022). Association between age at first calving, first lactation traits and lifetime productivity in Murrah buffaloes. Animal Bioscience, 35(8), 1151\u0026ndash;1161.\u003c/p\u003e\n\u003cp\u003eTamboli, P., Bharadwaj, A., Chaurasiya, A., Bangar, Y. C., \u0026amp; Jerome, A. (2021). Genetic parameters for first lactation and lifetime traits of Nili-Ravi buffaloes. Frontiers in Veterinary Science, 8, 557468.\u003c/p\u003e\n\u003cp\u003eTekerli, M. (2022). Manda yıldızı veri kayıt, hesap ve proje takip programı. Afyon Kocatepe \u0026Uuml;niversitesi.\u003c/p\u003e\n\u003cp\u003eThiruvenkadan, A.K., Panneerselvam, S., Rajendran, R. (2015). Lifetime performance of Murrah buffaloes hot and humid climate of Tamil Nadu, India. Buff Bull; 34:92-9.\u003c/p\u003e\n\u003cp\u003eUğurlu, M. (2017). D\u0026uuml;nyada ve T\u0026uuml;rkiye\u0026apos;de Manda Yetiştiriciliği, Manda Irkları ve Verim \u0026Ouml;zellikleri. J Anim Nutr\u0026amp;Nutr Dis-Special Topics, 2017, s.3(2):77-83.\u003c/p\u003e\n\u003cp\u003eVerma, R., Singh, I., Balhara, A.K., Nayan, V., Sharma, R.K., \u0026amp; Chaudhiry, V. (2018). Correlation between extremes age at first calving with their productive and reproductive performances in Indian Murrah buffaloes (Bubalu sbubalis). Indian Journal of Animal Research, 52(10), 1506-1512.\u003c/p\u003e\n\u003cp\u003eYılmaz, A., Kara, M.A. (2019). D\u0026uuml;nyada ve T\u0026uuml;rkiye\u0026rsquo;de Manda Yetiştiriciliğinin Durumu ve Geleceği. Turk J Agric Res, 2019, s.6(3): 356-363.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eYılmaz, M.A., Kaymaz, M., Erg\u0026uuml;n, Y. (2024). Development, Quality, and Production Parameters of In Vitro Embryo in Anatolian Water Buffaloes. Tropical Animal Science Journal, 47(1).\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"tropical-animal-health-and-production","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"trop","sideBox":"Learn more about [Tropical Animal Health and Production](https://www.springer.com/journal/11250)","snPcode":"11250","submissionUrl":"https://submission.nature.com/new-submission/11250/3","title":"Tropical Animal Health and Production","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Anatolian buffalo, age at first calving, reproductive parameters, herd life","lastPublishedDoi":"10.21203/rs.3.rs-8578115/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8578115/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study was conducted to investigate the effects of age at first calving (AFC) on calving interval (CI), service period (SP), number of calvings (NC), productive life (RL), reproductive life (PL), and herd life (HL) in Anatolian buffaloes. The dataset consisted of records from 641 breeding female buffaloes and their 2,256 calves born over the years in 89 farms between 2012 and 2022. Breeding female buffaloes were classified into three groups according to their age at first calving as \u0026le;\u0026thinsp;37.99 months (Group 1, n\u0026thinsp;=\u0026thinsp;271), 38\u0026ndash;49.99 months (Group 2, n\u0026thinsp;=\u0026thinsp;228), or \u0026ge;\u0026thinsp;50 months (Group 3, n\u0026thinsp;=\u0026thinsp;142). Age at first calving differed statistically among Groups 1, 2, and 3 (34.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15, 43.73\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25, and 61.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84 months, respectively) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). RL was higher in Group 1 (58.79\u0026thinsp;\u0026plusmn;\u0026thinsp;2.41) than in Group 3 (45.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87); PL was higher in Group 1 (61.03\u0026thinsp;\u0026plusmn;\u0026thinsp;4.48) than in Groups 2 and 3 (50.72\u0026thinsp;\u0026plusmn;\u0026thinsp;2.07 and 43.77\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87, respectively); and HL was higher in Group 3 (104.08\u0026thinsp;\u0026plusmn;\u0026thinsp;2.01) than in Groups 1 and 2 (91.24\u0026thinsp;\u0026plusmn;\u0026thinsp;2.39 and 94.68\u0026thinsp;\u0026plusmn;\u0026thinsp;2.01, respectively) (p\u0026thinsp;=\u0026thinsp;0.000). A strong positive correlation was found between age at first conception and AFC (r\u0026thinsp;=\u0026thinsp;0.998), and between CI and SP (r\u0026thinsp;=\u0026thinsp;0.997) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Age at first calving (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), SP (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), NC (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and HL (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) were identified as factors influencing reproductive life. In conclusion, late first calving (\u0026ge;\u0026thinsp;50 months) in Anatolian buffaloes reduces reproductive efficiency and leads to economic losses, while early first calving (\u0026le;\u0026thinsp;37.99 months) increases herd productivity and the total number of calvings. Since age at first calving is critical for reproductive performance and lifelong reproductive activity, it is recommended to reduce age at first calving through improvements in nutrition, health, and genetic management.\u003c/p\u003e","manuscriptTitle":"Effects of Age at First Calving on Some Reproductive and Herd Parameters in Anatolian Buffaloes","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-09 09:42:45","doi":"10.21203/rs.3.rs-8578115/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2026-02-09T05:50:30+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-04T11:17:14+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-16T04:40:07+00:00","index":"","fulltext":""},{"type":"submitted","content":"Tropical Animal Health and Production","date":"2026-01-13T03:15:40+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"tropical-animal-health-and-production","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"trop","sideBox":"Learn more about [Tropical Animal Health and Production](https://www.springer.com/journal/11250)","snPcode":"11250","submissionUrl":"https://submission.nature.com/new-submission/11250/3","title":"Tropical Animal Health and Production","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"1b92ac73-4d0d-4803-a022-e074fdc60b74","owner":[],"postedDate":"February 9th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-02-09T09:42:45+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-09 09:42:45","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8578115","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8578115","identity":"rs-8578115","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}