1. A study has been made of the assimilation and retention of nitrogen, phosphorus and calcium by calves fed on raw and pasteurized milks. Sixteen calves were used in the experiments.
2. No significant differences were found between the two types of milk.
3. An examination of the percentage retentions of nitrogen, phosphorus and calcium indicates that milk is relatively deficient in calcium and to a less extent in phosphorus when used as the sole food for calves. The N/Ca balance can be improved by including pasture grass or hay in the ration.