Inheritance and relationships of linear type traits for age groups of Holsteins

Routine classifications from the linear type trait program of the Holstein Association were analyzed separately for age groups. Inheritance of linear type traits and their genetic and phenotypic relationships were evaluated. Estimates of genetic and phenotypic parameters were compared to other studies with experimental classifications from the Holstein Association and with data from artificial insemination organizations across age groups. Evaluation of sires for type traits across age groups may not properly rank sires if ages of daughters differ for sires. Future genetic evaluations of type by the Holstein Association will consider only classifications of cows closest to 30 mo, so heritabilities for linear type traits for only 2 yr olds from this study may have application. Some linear type traits are very similar genetically. Stature has substantial genetic association with final score as subjectively assigned by classifiers.