Pedigree Selection and Semen Banking of Young Dairy Sires for Artificial Insemination

Abstract

A conventional system of progeny testing young dairy bulls was compared to pedigree selection of young bulls for semen banking and disposal prior to proving. The proportion of bulls expected to be culled incorrectly on their pedigrees was computed in a joint bivariate normal distribution of pedigree and progeny test evaluations. Theoretical expectations agreed well with actual results generated by hypothetical pedigree selection among bulls sampled in artificial insemination.Under most situations examined, some pedigree selection with semen banking produced slight to moderate decreases in the price of semen required to meet total testing costs (break-even semen price) and slight to moderate increases in the number of bulls tested at a fixed break-even semen price. Pedigree selection was most advantageous where a high proportion of bulls tested was returned to service, where the correlation between pedigree and progeny test evaluations of a bull was high, and where holding costs represented a high proportion of total testing costs. However, the advantages of pedigree selection and early disposal of young bulls would not be sufficient to increase appreciably the rate of genetic improvement where few bulls are sampled per year.