Progeny Tested Sires Compared with Pedigree Selected Young Sires

Abstract

First lactation records of 109,589 cows in 1,978 Holstein herds cooperating with three artificial insemination studs in young sire sampling were studied to compare performance of progeny of approximately the upper 15, 2, and 25% of sires, dams, and maternal grandsires for milk yield with selection differentials of +350, +2735, and +268kg milk when the young sires entered sampling programs. The 315 young bulls were sired by 88 sires.Mean weighted Predicted Differences for sires proven through artificial insemination were 130kg milk and 4.0kg fat, whereas weighted averages for naturally proven sires were 13kg milk and .4kg fat. For young sires, pedigree index of sire, dam, and maternal grandsire averaged 347kg milk and 11.8kg fat, and for an index including sire and maternal grandsire averaged 242kg milk and 7.6kg fat. Annual trends for ancestors were +31.8kg milk and +.9kg fat for sires.Within herd-year-season, production of daughters of progeny tested sires exceeded that of daughters of young sires by 84kg milk and 2.4kg fat. Progeny of young sires produced 103kg more milk than daughters of naturally tested bulls.