Utilization of Genetically Elite Holstein Cows

Merit of service sires for Holstein cows designated as genetically elite for yield in January 1990 was calculated to determine the contribution of these cows to genetic progress. Service sires were determined from sires of registered female progeny because male progeny were selectively registered. Primary data were 1295 elite cows (top 1%) that had a daughter produced from a mating in the 6 mo following the January 1990 evaluation and 209 service sires for those elite cows. Seven percent of the elite cows were mated to bulls that not only lacked an evaluation but also had generally low pedigree promise. The average economic index of evaluated service sires based on their genetic evaluations for milk, fat, and protein yields was at percentile 91 (ranking based on active AI bulls). Five percent of these bulls were below percentile 50. Although 71% of the bulls were at or above percentile 90, only 13% were at or above percentile 95, which was only slightly greater than the 12% for service sires of all registered cows. The lack of emphasis on yield traits was partially explained by a low or missing final score for type for the elite cow, which may have made her unacceptable as a bull-dam. The number of service sires and the modest service sire merit suggest that elite Holstein cows are underutilized. However, dependence on elite designation for selection of bulldams is decreasing, as evidenced by the many young cows without evaluations that were mated to produce sons for sampling. Received October 22, 1992. Accepted January 13, 1993. (