EFFECTS OF SOYBEAN HULLS AS ENERGY AND PROTEIN SOURCES IN DAIRY COW DIET ON PERFORMANCE OF LACTATING DAIRY COWS

The effects of feeding soybean hulls as energy and protein sources in concentrate on the performance of lactating dairy cows were studied. Twenty four Holstein Friesian crossbred (>87.5 % Holstein Friesian) lactating dairy cows, averaging 16.3 + 1.4 kg/d of milk, 84 + 15 days in milk, 42 + 5 mo old, and 415 + 20 kg body weight, were blocked by milking days first and then by milk yield, body weight, and age into 2 groups of 12 cows. Cows within each group were further randomly assigned to 3 treatments of 8 cows each. The treatments were control (0 % soybean hull (SH)), 10 % SH and 20 % SH in the concentrates. Performance parameters showed that DM intake, CP intake, NELP intake, milk yield, milk composition, and body weight change were similar in all treatments. However, milk fat and milk protein contents tended to linearly increase with increasing soybean hull in the concentrates while total solid content was significantly linearly increased by the addition of SH. Concentrations of ruminal ammonia nitro-gen, volatile fatty acids, and pH were unaffected by the treatments. Milk fatty acid contents were also similar in all treatments except for C18:2 and C18:3 that were significantly linearly increased by the addition of SH. The present study suggested that SH can effectively replace high cost starchy ground corn in the concentrates. Levels of SH addition in the concentrate should not be in excess of 20 % and SH can replace ground corn up to 100 % in the concentrate