Breeding Programs of Dairymen Selecting Holstein Sires by Computer

Abstract

A computerized linear program (MAXBULL) selects groups of sires to attain or exceed goals of dairymen and maximize weighted average Predicted Difference for milk. Goals for 196 dairymen with Holsteins in the spring of 1982 averaged −.05 Predicted Difference fat percent, .85 Predicted Difference type, $17.52 per unit, and percents net superiority 29, 35, 36, 27, 33, and 46 for descriptive traits udder support, rear udder, fore udder, teats, hind legs, and feet. Percent net superiority is the percentage of units from sires having a significant number of superior daughters in a trait, reduced by the percentage of units from sires having a significant number of inferior daughters. Associated Predicted Difference milk, fat, and dollars were 789 kg, 25 kg, and $215. All goals exceeded averages of artificial insemination sires available, and Predicted Difference dollars exceeded Virginia service sire averages by $44 and the 90th percentile sire by $6. Predicted Difference fat percent was the most frequently binding production trait, whereas udder support was the most frequently binding type trait. Predicted Difference fat percent and price were most influential on maximum Predicted Difference milk. Breeding programs of dairymen using bulls from one organization differed from those using bulls from several organizations. © 1983, American Dairy Science Association. All rights reserved.