The effect of level and pattern of feeding on the yield of milk constituents from cows of different yield potential

Abstract

SUMMARY: Data from three dairy-cow nutrition experiments have been analysed in terms of the yields of milk, lactose, fat and protein. Yields of the three constituents varied linearly with milk yield. However, yields of fat from individual cows were much more variable at high milk yields than were the other two constituents. Patterns of feeding had relatively little effect on the pattern of protein yield in cows fed to their production potential but could be important in influencing yields of fat.Predicted responses of protein and fat yields to increments of feed were generally small in cows being fed according to their predicted yield potential and the conversion of metabolizable energy to milk constituents was of a low biological efficiency.