Progeny Tested Sires Compared with Pedigree Selected Young Sires

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Abstract
First lactation records of 109,589 cows in 1978 Holstein herds cooperating with 3 artificial insemination [AI] 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 +268 kg 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 AI were 130 kg milk and 4.0 kg fat and weighted average for naturally proven sires were 13 kg milk and 0.4 kg fat. For young sires, pedigree index of sire, dam and maternal grandsire averaged 347 kg milk and 11.8 kg fat and for an index including sire and maternal grandsire averaged 242 kg milk and 7.6 kg fat. Annual trends for ancestors were +31.8 kg milk and +0.9 fat for sires. Within herd-yr-season, production of daughters of progeny tested sires exceeded that of daughters of young sires by 84 kg milk and 2.4 kg fat. Progeny of young sires produced 103 kg more milk than daughters of naturally tested bulls.