568. The rate of secretion of milk and fat

Abstract

1. The effects of variations in the length of the milking interval and of the preceding milking interval were measured for five cows.2. The yield of milk increased with the lengths and decreased with the square of the lengths of the milking interval and of the previous milking interval.3. The yield of fat increased with the length of the milking interval and the length of the preceding milking interval and decreased with the square of the length of the milking interval.4. The biological implications of each of the mathematical terms are discussed.5. The effect of the preceding interval was through a direct carry-over of residual milk and also by an effect on the metabolic rate of the alveoli throughout the following interval.6. The rate of secretion of both milk and fat declined with increasing milking interval; there was evidence that the rate of decline for the milk was greater than that for the fat, for the fat percentage of the milk tended to increase.