Phenotypic and Genetic Parameters of Some Production Traits of Holstein Friesian Cows Raised at the State Farm of Koças
In this researh, six reproductive and three milk yield traits were determined and genetic and phenotypic parameters were estimated for these nine traits in the Holstein Friesian cows reared at the State Farm of Koças in Aksaray (Turkey). The least squares means of fırst service age (FSA), fırst calving age (FCA), calving interval (CI), number of insemination per conception (NIPC), gestation length (GL), service period (SP), lactation milk yield (LMY) , lactation length (LL), and dry period (DP) were 560.80±3.07 days, 855.43±2.66 days, 382.30±6.42 days, 1.76±0.06, 285.05±1.66 days, 110.57±6.28, 6937.63±1 09.46 kg, 320.51±3.29 days, 69.51±3.08 days and respectively. Heritabilities of these traits were 0.55±0.151, 0.69±0.162, 0.06±0.086, 0.04±0.062, 0.11±0.085, 0.21±0.000, 0.20±0.11, 0.078±0.007, and 0.34±0.000, respectively. The repeatibilities of CI, LPC, GL, SP, LMY, LL, and DP were 0.12, 0.042, 0.32, 0.44, 0.37, 0.065, and 0.42, respectively. The year had a significant effect on the FSA, CI, SP, and LMY at (p<O.OI) levels. lt was shown that lactation number had a significant effect on NIPC, LMY, and DP, the sex of calf had a significant effect on GL, the calving season had a significant effect on LMY, and DP at (p<0.01) levels. Also, linear regressions of LMY to LL, SP to LL, and LL to LMY statistically significant.
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