Improving prediction of national evaluations by use of data from other countries

National and international Holstein bull evaluations from Canada, France, Germany, Italy, The Netherlands, and the US were examined to determine whether inclusion of data from other countries increased the accuracy of prediction of national evaluations for milk, fat, and protein yields. The six national and six international evaluations from February 1995 were compared with national evaluations in January and February 1999. The later national evaluations were assumed to be improved estimates of true genetic merit because of added data. Correlations with later national evaluations generally were larger for earlier national evaluations than for international evaluations, probably because of the larger part-whole relationship between earlier and later national evaluations. However, standard deviations of difference of 1995 evaluations from later national evaluation were lower for international evaluations than for earlier national evaluations, which suggested improved prediction from inclusion of multinational data. For bulls with substantial increases in daughters, nationally and internationally, correlations were higher, and standard deviations of differences were lower for international evaluations compared with earlier national evaluations. Inclusion of multinational data improved the prediction of future national evaluations, especially for countries that import genetics of dairy cattle.