Abstract
Calcium, copper and zinc contents in the pasture grass and the incidence of epiphysitis of the fetlock joint were surveyed on the breeding farms in the western, central and eastern area in Hidaka district, Hokkaido, Japan. 25 farms and 278 foals were used in this study.
The averages of calcium, copper and zinc contents were 0.363%, 7.08ppm and 26.4ppm respectively, and they were lower than the contents of feed composition tables on NRC. Copper contents in the central area was significantly lower than those in other areas. The incidence of epiphysitis of the fetlock joint was 23.0% (64 foals) and their ages ranged from 100-200 days old. The incidence of epiphysitis of the fetlock joint in the foals grown at the pastures in which copper contents were lower was 34.3%, it was significantly higher than others. But there were no relationships in the cases of calcium and zinc.
