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Correlations between Type Components of Ayrshire Heifers and Cows¹

Department of Dairy Husbandry, West Virginia University, Morgantown

ABSTRACT

For many years, body conformation of dairy cattle has received considerable emphasis in their selection for breeding purposes. In recent years, the question of whether one might satisfactorily select heifers which would develop into animals of desirable type conformation after they freshen has received additional attention.

Some of the previous work on this subject included that of Johnson and Lush (3) with Holstein data; Hyatt et al. (2) with Ayrshire data, and Harvey et al. (1) with Jersey and Holstein data. Johnson and Lush found that little confidence could be placed in ratings made under one year of age, because of the small correlation between these and future ratings. Classification ratings made at ages over one year, but before freshening, were slightly more reliable, being about as repeatable as intraherd records of production.

Findings of Hyatt et al., in an analysis of Ayrshire records, were similar to results reported by Johnson and Lush, except that they did not observe quite as much difference between classifications made on the animals under one year of age and those over one year of age.

¹ Published with the approval of the Director of the West Virginia Agricultural Experiment Station, as Scientific Paper No. 496.