Protein Supplementation of Ammoniated Roughages. II. Wheat Straw Supplemented with Alfalfa, Blood Meal or Soybean Meal Fed to Wintering Steers

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