Dairy bull fertility receives in general scarce attention. However, the fertility of the bull is critical in determining the reproductive performance of the herd. Indeed, some studies have shown that a significant percentage of reproductive failure is attributable to bull subfertility.
The trait SCR is defined as the expected difference in conception rate of a given bull compared to the mean of all other evaluated bulls; in other words, a bull with an SCR value of +5.0% is expected to achieve a conception rate of 36% in a herd that normally averages 31% and uses average SCR bulls. Contrary to evaluations for other traits such as production or cow fertility, SCR is designed as a phenotypic rather than a genetic evaluation, because the published estimates include not only genetic but also non-genetic effects.
Recently, we evaluated the feasibility of predicting SCR using genomic data. Notably, our findings suggest that genomic prediction of service sire fertility is feasible. This could be the foundation for the development of genomic tools that help the dairy industry to make accurate genome-guided decisions, such as early culling of predicted subfertile bull calves.
For more information, contact Dr. Peñagaricano at <[email protected]> or call (352) 392-1981 ext. 231.