Grass Silage vs. Hay for Lactating Dairy Cows

Two types of experiments were conducted to determine the relative feeding value of silage and hay harvested from the same field at the same stage of maturity.In Experiment I, alfalfa silage was fed ad libitum and hay feeding controlled to 0, 25, 50, 75, and 100% of the ration dry matter.Combined data from two trials showed significantly (P < 0.05) greater dry matter consumption per 100 lb body weight of groups fed all-hay, 75% hay, and 50% hay, than of groups fed all-silage rations.In general, milk production followed a similar trend as dry matter consumption; however, differences among groups were not statistically significant.In like manner, differences among groups in persistency of milk production and body weight gains were not significant.There was a general trend for body weight gain to increase as the level of hay in the ration increased.In a second experiment, grain feeding significantly (P < 0.01) decreased dry matter consumption from either hay or silage, but significantly (P < 0.01) increased total dry matter consumption (roughage plus grain dry matter).In this study, cows consuming silage produced significantly (P < 0.01) more milk than cows consuming hay.The average daily 4% FClY[ production of cows fed hay was 27.2 lb, as compared to 32.7 lb for cows fed silage.In like manner, the average daily 4% FCIVI production of cows fed only roughage (hay or silage) was 25.8 lb, compared to 33.2 lb for cows fed roughage plus grain.A greater milk production response was obtained from feeding grain to cows consuming silage than to cows consuming hay.