Analysis of Deviations of Dairy Records from Different Contemporary Averages

Abstract

Many investigators have expressed dairy records as deviations from various contemporary averages because of the computational difficulties of analyzing large numbers of records according to complex models. The expectations of the sums of squares and cross products of deviations from four contemporary averages in one-way classification analyses were determined in terms of a more complex model. The expectations were then compared with estimates obtained from the analysis of 59,902 milk and fat records of cows sired by 353 Holstein sires used in artificial insemination. The agreement between the theoretical and actual results was very close, which indicates the validity of the assumptions and models used.