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Heritabilities of Angus Classification Scores¹

Iowa State University,^,3 Ames 50010

Abstract

Heritabilities of type classification scores on Angus cattle were estimated. The data were collected from 1958 through 1971. The covariances among paternal half-sibs and between parent and offspring were used to estimate heritability. Factors influencing the heritability estimates were investigated. No attempt was made to consider the economic value of the classification scores or their correlation to production traits.

In general, the heritabilities of Angus classification scores were moderate to high when type was evaluated subjectively. Based on this evidence of genetic variability, both within and across herds in the cattle population, rapid changes in type to conform to new ideals and goals are not surprising.

For records on animals classified at the same time by the same classifier and in the same herd, probable heritabilities were 0.55 for conformation, size, head and breed character, feet and legs, rearquarters and total score; 0.50 for rib and back, loin and rump; and 0.30 for shoulder and foreribs.

¹ Journal Paper No. J-7534 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project No. 1704.

² The authors acknowledge the assistance of Mrs. Iris Pankau, Fred Francis and Lloyd Miller, Secretary, American Angus Association.

³ Department of Animal Science.