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Where should young sires fit in your breeding program?

Dairy Pipeline: September 1996

by Bennet Cassell
Extension Dairy Scientist
Genetics and Management
Virginia Tech

Young sires in major AI stud sampling programs usually are the progeny of the best sires and dams available in each breed. Only rarely would an individual dairy farmer be able to use a bull of comparable pedigree merit in natural service. Most young-sire use is restricted to organized sampling programs run by the studs, but young sires can also be used outside of such programs. Just how good is this fall's crop of sample sires? A recent study of genetic merit of sample sires and proven Holstein bulls from the 1980s (J. Dairy Sci. 78:2481) showed that the average young sire ranked at the 57th percentile for MFP$. That's too low a ranking to replace carefully selected proven sires with random sample sires in a breeding program. That study showed that eliminating the poorest 25% of pedigrees for MFP$ raised the average rank to the 68th percentile, a figure that compares favorably with the average rank of proven service sires used across the state. Using only the top 25% of AI sample sires would increase their rank relative to proven bulls available at the same time to the 84th percentile. I am not aware of any studs which have marketed their very top pedigrees for MFP$ as an alternative to lower ranking proven bulls, but this study showed selected young sires to be a better choice. For farmers willing to screen some pedigrees, selected AI sample sires are a cost effective way to make genetic progress. The youngsters won't replace the top proven bulls, but the best pedigrees of a group of young sires certainly can equal the lower ranking proven bulls for genetic progress.

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