Relationships between evaluations of Canadian and USA Holstein bulls for longevity and somatic cell score

Canadian and United States evaluations of Holstein bulls were compared for longevity and somatic cell score. A total of 13 236 bulls was evaluated for longevity with 462 bulls having evaluations in both countries, and 10 945 bulls evaluated for somatic cell score with 564 bulls having evaluations in both countries. Multiple across country evaluation procedures were used to estimate the genetic correlations between countries, and to evaluate all bulls on each country’s scale of expression. The genetic correlation for longevity (calculated and expressed differently in each country) was 0.91, and for somatic cell score was 0.93, which were as high as correlation estimates for production traits between many countries. The correlation between the international evaluation and the original Canadian evaluations were 0.971 for functional herdlife and 0.981 for somatic cell score, and for the United States were 0.999 and 0.997, respectively. International comparisons of bulls for traits other than production and conformation are feasible.  2000 Elsevier Science B.V. All rights reserved.