Cow evaluation in North America

Abstract

Pearson, R.E. and Miller, R.H., 1978. Cow evaluation in North America. Livest. Prod. Sci., 5: 19--28. To date, cows have been evaluated both genetically and phenotypically primarily for milk and fat yield. For these traits, the estimation procedure is quite sophisticated. Although procedures in DHI computing centers vary considerably, many dairymen on test receive routine estimates of the producing and transmitting ability of their cows. The degree to which this information is used appears to be highly dependent upon the effectiveness of the extension education program in the particular state. The cow index calculated by the USDA has become the major criterion of selection for dams of young bulls. Estimates of breeding values of cows for other traits are nearly nonexistent. As the economic importance of other traits is determined, procedures for obtaining data and for estimating breeding values will need to be developed. Presently, culling guides are based mainly on current lactation production or on production on current test day. Little emphasis has been placed on projection of net returns.