Date of this Version
Two winter steer growth trials were conducted to investigate responses of steer calves to ammoniation of wheat straw, level of alfalfa haylage (50 or 66.7% of diet) and source of supplemental protein, soybean meal (SBM), blood meal (BM), or a blood meal-urea mixture (BM-U). In trial 1, the main effect of arnmoniation significantly increased average daily gain (ADG) from .15 to .24 kg/d, dry matter intake (DMI) from 4.86 to 5.29 kg/d and gain/feed from .029 to .044. The higher level of alfalfa haylage significantly increased DMI from 4.78 to 5.36 kg/d. Gain during a subsequent grazing period was unaffected by winter diet. In trial 2, the main effect of ammoniation significantly increased ADG from .26 to .38 kg/d and DM1 from 4.28 to 4.78 kg/d. The main effect of supplement showed that ADG was significantly greater for the SBM-fed steers than for either the BM- or BM-U-fed steers. A significant ammonia X supplement interaction was noted for gain/feed; the response due to protein supplement differed, depending on whether or not the straw was ammoniated.