Effects of pedigree and exotic genetic inheritance on semen production traits of dairy bulls

Abstract

Objective: To study the effects of different levels of exotic inheritance on ejaculate quality in bulls and its passage through different generations. Methods: Data on semen production traits and ejaculate quality were obtained for 38 crossbred bulls and grandsire-sire-progeny relationship in relation to semen quality was studied. The bulls were classified into three groups based on the level of exotic inheritance viz. F1, 50.0%-62.5% exotic germplasm and >75% exotic germplasm. Results: Results of the present study indicated that about 40% of the ejaculates obtained from the crossbred bulls were rejected from further processing due to poor ejaculate quality. The F1 bulls produced significantly higher proportions (57.00±10.00) of poor quality ejaculates compared to the interse mated bulls. The age at first semen collection in crossbred bulls ranged from 567 to 1 010 days with an average of 738.89±18.18 days while the mean age at first semen freezing was 865.72±34.60 days. Conclusions: It may be inferred that the “acceptable quality semen producing ability” decreased from grandsire through sire to male progeny and among the increasing exotic genetic levels of CB cattle, F1 bulls produced significantly higher “low grade ejaculates” that were unfit for cryopreservation.

Keywords

• Crossbreeding
• Semen quality
• Ejaculate rejection rate
• Exotic germplasm level