Some factors affecting total milk yield and service per conception and estimated breeding value with sex ratio of Holstein Friesian cows in central Iraq

Abstract

A total of 2718 records belong to 1126 Holstein Friesian cows which divided to 911 cows in Al-Nasr station for dairy cattle and 215 cows in Al-Ishaky station for the period of 1994-2003 which they are daughters of 28 bulls in Abu-Ghraib Artificial Insemination Center . Total milk yield (TMY), service per conception (S/C), and sex ratio (SR) were studied.البحث مستل من رسالة ماجستير للباحث الثانيThe overall mean ± SE for TMY and S/C were 3774.11 ± 28.80 kg and 2.02 ± 0.03 insemination respectively. TMY was highly significant affected by herd , parity , season and year of calving , while age at first calving showed no significant effect on production. S/C was affected significantly (P 0.01) for all factors which mentioned previously. The statistical analysis showed a lack of significant differences between male and female births, with the mean ratio of 53.1 : 46.9 for 3033 births in two stations , but for the bull No. 543 (SR) was 67.8 : 32.2 (P 0.01).The breeding value for bulls which used A.I. center for TMY ranged between – 590 to 539.1 kg and for S/C ranged between – 0.384 to 0.450 insemination.