Relative Economic Values Assigned to Milk, Fat Test, and Type in Pricing of Bull Semen

摘要

Data on 324 Holstein bulls from the July 1983 USDA Sire Summary and Holstein Association type evaluations were analyzed using multiple regression to determine which traits or combination of traits in a sire evaluation are most important in determining the price of a straw of semen. Over all bull studs, type was a major economic influence in determining price of semen. When bulls with outlier prices ($100 or more) were excluded, relative economic values over all buII studs were 4.31:2.63:1 for milk, type, and fat test. For three bull studs with more than 35 bulls with evaluations for milk, type, and fat test, relative economic values (values per phenotypic standard deviation) were 3.16:1.35:1, 4.81:1.93:1, and 4.06:2.15:1. With so much economic emphasis on type and fat test, genetic gain in milk production from the sire of cow path would be substantially less than if selection were for milk production alone. Unusual bulls (outlier prices) were associated with nonlinear economic values. When outliers were excluded, models including functions of sire evaluations accounted for 50 to 75% of the variation in semen prices.