Utilizing Both Part and Complete Daughter Records in Sire Evaluation

Abstract

A three-stage program for evaluating sires used in artificial insemination is proposed. The first stage consists of acceptance or rejection of sires based on the part-lactation (5-mo.) records of their daughters. The second stage utilizes both part records and complete records of other daughters. The third and final stage provides for evaluation dependent on complete records alone. Selection index equations are presented for estimating the breeding value of sires for these combinations of information. The correlations between estimated and true breeding value are given in an example which illustrates the additional knowledge available in evaluating sires when part records are utilized. For example, ten 5-mo. records have the expected correlation with true breeding value of 0.58, as opposed to 0.00 if only complete records are used; 20, 5-mo. records, a correlation of 0.69 as opposed to 0.00; 20, 5-mo. and ten complete records, 0.78 as opposed to 0.61; and ten 5-mo. and 20 complete records, 0.79 as opposed to 0.74.