Abstract
The proportion of animals recovering after a single treatment for milk fever was higher among cows which grazed during the summer, and which were tied up in stalls during the winter, than among cows which were tied up in stalls the whole year. This was true both for cows treated during the period May-September, roughly corresponding to the grazing season, and those treated during the period October-April. During the period May-September recovery rate after one treatment was also higher in the group at pasture than in cows which were loose-housed. The proportion of animals which did not recover was higher in cows in stalls with slippery flooring, than in cows which were provided with a secure foothold. The relationship between various environmental factors and susceptibility to muscle damage was studied on the basis of serum activities of aspartate aminotransferase, alanine aminotransferase and creatine kinase.