The Effects of Varied Rates of Hay Feeding on Body Weight and Production of Lactating Dairy Cows

Abstract
Twenty lactating Holstein cows were used in 2 trials to test the effects of feeding hay at levels of 0.50, 1.17, 1.83 and 2.50 lb./100 lb. body weight. There were no significant effects of level of hay feeding on body weight change. If TDN or ENE was held constant, there were no significant effects of level of hay feeding on milk production. Body weight change was not correlated with either milk production or efficiency of production. TDN available for milk production was highly correlated with milk production (co-effecient of correlation 0.941). ENE available for milk production had a coefficient of correlation of 0.942 with milk production. Based on this experiment, neither TDN or ENE could definitely be said to be superior to the other as an estimator of the worth of a ration, though ENE did seem to be somewhat more consistent over a wide range of hay, concentrate ratios. Both protein and dry matter digestibility values declined as hay content of the ration increased.