Relationships Between Sire Proofs

Summary Correlations were obtained between nonartificial insemination (A.I.) daughter-dam comparisons, A.I. daughter-dam comparisons, non-A.I. herd-mate comparisons, the United States Department of Agriculture (USDA) A.I. daughter herd-mate differences, and the Cornell daughter level. It was found that non-A.I. herd-mate comparisons were more effective in predicting future production of daughters under A.I. conditions than were non-A.I. daughter-dam comparisons. Using the Cornell daughter-level figures, corrected for numbers, it was shown that non-A.I. daughter-dam comparisons on 40 pairs was equivalent to the information on two or three A.I. daughters in different herds. Under similar conditions the information from 48 natural service herd-mate comparisons was equivalent to the information from 9 to 13 A.I. daughters. It was concluded that non-A.I. herd-mate comparisons are of much higher value than non-A.I. daughter-dam comparisons in evaluating the daughters of a bull. The non-A.I. herd-mate comparison would need to be regressed further to correct for numbers than the A.I. herd-mates, so as to give as good an estimate of production of future daughters.