Effect of Protein Level in Calf Starters on the Growth Rate and Metabolism of Young Calves

Abstract

Summary Eighty two-day-old male and female calves representing the Holstein and Jersey breeds were used in two separate experiments, to determine the effect of protein level of calf starters on growth rate and metabolism of young dairy calves. In the first experiment, no significant differences were observed in growth rates of calves receiving starters containing either 12.2, 16.6, 20.2, or 24.3% crude protein. The most efficient gains made were on the 12.2 and 16.6% protein levels. In the second experiment, no significant differences were found among groups receiving either a 13.0, 20.0, or 23.7% crude protein starter. A starter containing only 8.5% crude protein supported growth at a significantly lower rate than any of the other starters. A 16.6% crude protein starter gave growth superior to any of the other groups, which may be explained in part by increased feed consumption. The most efficient gains as measured in terms of pounds of feed required per pound of gain were made by this group. The digestibility, nitrogen balance, and blood studies tended to confirm results obtained from growth studies. Based on these studies, it appears that dairy calves two to 84 days of age do not require starters containing more than 12.0 to 16.0% crude protein, to maintain normal growth when a limited amount of whole milk and a medium to good quality alfalfa hay are fed. It was also shown that starters containing only 8.5% crude protein would not support normal growth, thereby indicating that the minimum protein level of calf starters is in excess of 8.5% crude protein.