Factors associated with mortality to 21 days of life in dairy heifers in the United States

Results from the first national study of US dairy heifer health indicated that factors associated with mortality in the first 21 days of life included first colostrum-feed ing method, timing, and volume; time of separation from dam; calving ease; and twin birth. Population attributable fraction estimates demonstrated the importance of these factors in preventing early calfhood mortality. This analysis indicated that up to 31% of dairy heifer mortality during the first 21 days of life could be prevented by changes in first colostrum feeding method, timing, and volume. Similar analyses for time of separation from dam, calving ease, and twin birth indicated that 16%, 12%, and 3%, respectively, of mortality in the first 21 days of life could be prevented.