Published in Scientific Works. Series C. Veterinary Medicine, Vol. LXI
Written by Tahir BAYRIL, Orhan YILMAZ
This study aimed to determine the effects of sire selection on survival rate of calf, milk yield and reproductive parameters in high-yield dairy heifers. In the study, milk yield and reproduction parameters of 293 Holstein heifers from 7 bulls were determined. It was obtained that the first insemination age was higher in the daughter of number 1 bull. This statistical difference outcame from the daughter of number 1 bull (P<0.05). When calved age was determined, the daughter of the number 1 bull were higher than those of 2, 5 and 7 bulls (P<0.05). There was no effect of sire on the conception length of heifers, however there was significant effect of sire on live weights of hiefer during insemination period (P<0.05). The effect of bull on birth weight of calves was significant (P<0.05). Birth weights of calves were highest in the daughters of number 2 and 7 bulls, were lowest in the daughters of number 1 and 5 bulls. The effect of sire on lactation milk yield, lactation length and lactaion peak duration of the daughter were not significant, however was significant on peak yield (P<0.05). The birth type was significant on survival rate of calves. Survival rate of single born was 3.5 time higher than twins. In conclusion, the selection of bulls was found effective on reproductive parameters and birth weights of calves, however was ineffective on the lactation milk yield, lactation length and lactation peak duration except peak milk yield.
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