Detecting heat and maintaining high conception rates continue to be the major challenges of reproductive management. Of these, conception rate is perhaps the most difficult to control. The results of recent Cornell research to identify the primary causes of conception failure are reported elsewhere in these proceedings. The bottom line of the project was that the effects of factors like bulls, A.I. technicians, month of semen collection, month of breeding, age of cow and breeding interval length were small. After they were accounted for, large differences in conception results between herds remained.
Nutrition is cited with increasing frequency as a cause of poor reproduction.
Each must be considered in herd evaluation. However, for the purposes of this discussion, we'll concentrate on new research and ideas on the effects of protein nutrition on reproductive performance. Protein is a critical nutrient in the dairy ration. Adequate amounts must be provided to maximize milk production. However, the results of several recent experiments suggest that concentrations of dietary protein thought to be necessary for maximum production may reduce fertility.