Linear Type Trait Analysis with Genetic Parameter Estimation

Abstract Data on 18 traits scored 1 to 50 from 21st Century Genetics mating appraisal program were analyzed. Cows (43,428) were scored for 16 traits by 21st Century Genetics evaluators; disposition and milkout were scored by the herd owner. Data were collected from September 1, 1979 to January 1, 1984. Significant sources of variation were herd-year of evaluation, age of animal, stage of lactation, and sire. Parameters were estimated by using a multiple-trait model that included herd-mate deviations for milk and fat as additional traits. Means ranged from 25.1 to 31.8, and standard deviations ranged from 5.54 to 9.07. Genetic correlations ranged from −.50 to .91 and generally are larger than their corresponding phenotypic correlations. Genetic correlations >¦.50¦ were found between traits close in physical proximity or similarly defined. Heritabilities ranged from .08 to .42 and generally tended to be smaller than those previously estimated. All traits had significant least squares solutions for stage of lactation, but solutions were small (