Digestibility by ponies of oat straw treated with anhydrous ammonia

Abstract

ABSTRACTThe digestibility of oat straw treated with anhydrous ammonia was studied in four Shetland-type ponies in a 4×4 Latin square experiment. The experimental diets which contained soya bean oil meal, corn, sugarcane molasses, and 65% straw were: (1) straw treated with anhydrous ammonia, (2) untreated straw, (3) untreated straw plus urea, (4) untreated straw plus soya bean oil meal. Digestibility of the dry matter was 15% greater (P<0·01) and digestibility of cellulose 28% greater (P<0·01) in diets containing ammonia-treated straw than in those containing untreated straw. Ammonia treatment increased the nitrogen content of the straw by 50%, and nitrogen intake was 18% greater when the ponies were fed diet 1 than when fed diet 2. The nitrogen of the treated straw was utilized as efficiently as the nitrogen of the diet containing untreated straw supplemented with soya bean oil meal. However, the amount of nitrogen provided by the diet of ammonia-treated straw was not sufficient for nitrogen balance in the ponies. Ammonia treatment of oat straw did not affect the utilization of Ca, P, or Mg.