Genetic Assessment of Productive and Reproductive Traits in Friesian, Native, and Crossbred Cattle in Egypt

Abstract A total of 3023, 596, and 1189 lactation records for Friesian, Native, and their Crosses cows from 1994 to 2015 were utilized in this study to estimate and assess genetic and phenotypic parameters and breeding values for 305-day milk yield (305-DMY), lactation period (LP), calving interval (CI), and days open (DO) in these three genotype groups within the Egyptian context. Data were analyzed using the LSMLMW and MTDFREML programs. The analytical model included fixed effects such as season and year of calving, parity, and genotype groups, while random effects included animal and error. Unadjusted means for 305-DMY, LP, CI, and DO were as follows: 3597 kg, 362 days, 524 days, and 198 days for Friesian cows; 1399 kg, 199 days, 499 days, and 169 days for Native cows; and 2671 kg, 395 days, 556 days, and 215 days for Crosses cows. Genotype groups had a highly significant impact on all the studied traits. Heritability estimates were higher in both Crosses (0.32, 0.26, 0.25, 0.23) and Native cows (0.26, 0.28, 0.28) for productive and reproductive traits, respectively, compared to the Friesian cows (0.24, 0.22, 0.16, 0.17) for the same traits. Genetic correlations among productive and reproductive traits ranged from 0.10 to 0.86 for the three genotype groups, while corresponding phenotypic correlations were small to moderate and positive. The accuracy estimated for breeding values indicated that genetic improvement can be achieved through both sires and cows.