WHOLE CROP BARLEY AS CONSERVED FORAGE FOR LACTATING COWS

Abstract

Whole crop barley harvested as hay at the milk stage and at three stages of maturity as silage was fed to each of 16 lactating cows, over successive periods of 49 days each, according to a simple changeover design. The barley hay and barley silages contained 86.2, 26.1, 33.4, and 47.9% dry matter (DM), 14.2, 12.5, 11.1, and 9.2% crude protein, and 31.1, 34.1, 29.2, and 28.0% crude fiber for the hay, milk, soft dough, and firm dough stages of maturity, respectively. Forage DM intake was significantly lower (P < 0.05) for hay than for any of the silages and for the milk stage silage than for the more mature silages. There were no significant effects of diet on milk yield, but milk protein content was significantly lower (P < 0.05) and lactose content significantly higher (P < 0.05) when milk stage silage was fed compared with hay or the other silages. The ratio of acetate to propionate in the rumen fluid was significantly greater (P < 0.05) for cows fed hay than when fed silage. The apparent digestibilities of forage DM were 59.2, 59.4, 59.0, and 55.9% and the efficiencies of digestible energy utilization of complete rations corrected for body weight change were 49.1, 43.9, 42.2, and 42.3% for barley hay, and silages at the milk, soft dough, and firm dough stages of maturity, respectively.