Evaluation of a nonstarch polysaccharidase feed enzyme in dairy cow diets.

The objective of this study was to evaluate a commercial feed enzyme product (Natugrain 33-L; BASF Corporation, Ludwigshafen, Germany) used mainly in poultry diets for use in ruminant diets. The product contained mainly beta-glucanase, xylanase, and endocellulase activities. The study was conducted as a double 3 x 3 Latin square design with six lactating dairy cows (84 +/- 12 DIM) to measure intake, chewing activities, total tract digestion, and milk production. An additional three cows fitted with ruminal cannulae were used to measure dietary effects on ruminal fermentation and in sacco digestion characteristics. Cows received a diet consisting of 45% forage containing 0, 1.22, or 3.67 L of enzyme product/tonne of total mixed ration (DM basis). Using a low or high concentration of enzyme supplementation increased feed intake, but total tract digestibility only increased with the low concentration of enzyme. As a result, intake of digestible nutrients was increased to a greater extent for cows fed the low concentration than for cows fed the high concentration. Because the cows used in this experiment were in positive energy balance, increased intake of digestible energy due to enzyme supplementation did not increase milk yield or milk component yield. Further research is necessary to determine the mechanism by which adding a fibrolytic enzyme mixture enhanced intake, but only increased feed digestion when used at a low level.