Effect of Applying Ammonia or Fibrolytic Enzymes to Bermudagrass Hay on Feed Intake, Digestibility, and Growth of Beef Steers

This study evaluated the effects of the method of applying a commercial fibrolytic enzyme, Biocellulase A20 (A20), or ammonia to bermudagrass hay on the feed intake, digestibility, and growth performance of 50 AngusBrangus steers. Five-week fall regrowth of bermudagrass was harvested and treated with either anhydrous ammonia or A20 at rates of 3% dry matter (DM) and 15 g/ton of hay, respectively. The enzyme was applied immediately after harvesting (Ec), after a 72-h wilt and just before baling (Eb) or immediately before feeding (Ef). The hays were supplemented with cottonseed meal and soybean hulls at a rate of 1% of body weight (BW) and fed for 84 d. Dry matter intake and DM and fiber digestibility were greater in hays treated with ammonia or Ec than in untreated hays. However, growth performance was similar across treatments. This was largely due to the presence of the concentrate supplement in the ration. This study shows that the Ec treatment was as effective as ammonia at increasing the quality of 5-wk regrowth of bermudagrass hay.