Two cow trials and two lamb metabolism trials were conducted to evaluate methods of improving wheat straw. In the first cow trial and lamb metabolism trial, the treatments of wheat straw were: (1) none (control); (2) 40 g kg-1 of sodium hydroxide (NaOH); (3) 60 g kg-1 of a liquid supplement (LS); (4) 37.5 g kg-1 of anhydrous ammonia (NH3). In addition to wheat straw eaten ad libitum, all cows were given 7.5 kg of alfalfa-brome-grass hay three times weekly. In the second cow trial, the treatments of wheat straw were: (1) untreated straw plus 7.5 kg of alfalfa-bromegrass hay given three times weekly; (2) straw treated with NH3 (37.5 g kg-1) plus 7.5 kg of alfalfa-bromegrass hay given three times weekly; (3) straw treated with NH3; (4) straw treated with NH3 plus whey (227 g/day). Similar diets were given in the second lamb metabolism trial. The NH3 treatment of wheat straw given with alfalfa hay improved feed intake by an average of 13.8% (P < 0.01) in the two trials and cow gains by 0.3 kg/day (P < 0.05). In addition, NH3-treated straw alone increased gain (P < 0.05) by 0.1 kg when compared to untreated straw and hay in the second trial. However, LS- and NaOH-treated straw used in the first trial did not alter intake or gain. In the two lamb digestion trials, NH3 treatment increased lamb intake (P < 0.05) by an average of 29.2% and apparent dry matter digestibility (DMD; P < 0.05) by an average of 4.4%. No increase in apparent DMD was observed with NaOH or LS treatment of wheat straw. The NH3 treatment increased the apparent digestibility of acid detergent fibre, neutral detergent fibre and hemicellulose.
ASJC Scopus subject areas
- Animal Science and Zoology