Effect of a cellulase enzyme additive on hay intake and fiber digestion in goats

Thirty-six Spanish, Boer, and Boer × Spanish wethers (6 months of age, 25.0 ± 5.5 kg BW) were used to test the effect of a cellulose/hemicellulase enzyme additive on intake and fiber digestion. Wethers were blocked by BW and breed and randomized to 4 pens with Calan headgates to measure individual intake. Wethers were fed a chopped low quality grass hay (4.8% CP, 48.4 ADF, and 75.3 NDF) at 115% of average intake over the previous 3 d. Two pens of goats were offered a test supplement containing the enzymes and two were offered the control supplement. The supplement was composed of 5% of a mineral mix containing trace minerals, 8% liquid molasses, 43% soybean meal, and 44% ground corn. The enzyme preparation (69% distillers dried grains, 30% urea, and 1% enzymes) was incorporated into the supplement at the 2% level. The supplement was fed at 5.5 g/kg BW, resulting in 8.8 g of enzyme preparation/100 kg BW. Blood and ruminal fluid samples were collected prior to the morning feeding in wk 4 of the study for blood urea nitrogen and rumen ammonia. Following the 12-wk intake study, intake was reduced in half the pens to 80% of intake in week 12, fecal bags were fitted on animals, and fecal and ort samples were collected 5 days for determining digestibility. Data were analyzed with Proc MIXED of SAS. Rumen ammonia and blood urea nitrogen were similar for control and enzyme treatments (6.8 vs. 7.1 mg/dl, SE = 0.38, P > 0.20; 13.8 vs. 15.2 mg/dl, SE = 2.3, P > 0.20). Hay intake was similar for control and enzyme treatments (2.63% vs. 2.83 % of BW, P > 0.20; 58.8 vs. 63.0 g/kg BW0.75, P > 0.20). Dry matter digestibility and protein digestibility were similar (52.8 vs. 53.5%, SE = 1.1, P > 0.20; 79.4 vs. 78.4%, SE = 0.8, P > 0.20). Neutral detergent fiber digestibility and acid detergent digestibility also were similar (49.8 vs. 50.6%, SE = 1.5, P > 0.20; 26.9 vs. 25.5%, SE = 3.3, P > 0.20). The cellulose and hemicellulase additive did not improve intake of low quality grass hay or increase fiber digestibility in goats.