High feed costs and mounting consumer concerns about the use of antibiotic growth promoters (AGPs) in livestock production provide ample incentive to revisit and refine the use of enzymes in ruminant diets.
Enzymes can improve feed efficiency and reduce the cost of milk production. Feed additives with enzymatic fiber-degrading activity offer a potential to enhance forage digestion, feed efficiency and income over feed costs (IOFC). The application of a blend of cellulase and xylanase enzyme products to forages (corn silage and alfalfa hay) prior to feeding of 55:45 forage to concentrate diets can increase IOFC from $0.32 to $0.88 per cow daily.
When combining data from 20 studies and 41 treatments that added fiber-degrading exogenous enzymes to dairy cow diets, Canadian researchers reported overall increases in dry matter (DM) intake and milk yield of 2.2 ± 2.9 and 2.4 ± 3.3 lbs/day, respectively.
While the responses to the addition of fiber-degrading enzymes to dairy cow diets vary, the variability is not surprising because most of the commercially available enzyme products that have been evaluated as ruminant feed additives are produced for non-feed applications.
Feed enzymes for ruminants contain mainly cellulase and hemicellulase activities and are of fungal (mostly Trichoderma longibrachiatum, Aspergillus niger, A. oryzae) and bacterial (Bacillus spp.) origin.
Mode of action
Improvements in animal performance due to the use of feed enzymes have been attributed to increases in feed digestion.
In three studies conducted in lactating dairy cows, fiber degrading enzyme applications enhanced DM digestibility, 4 to 12 percent, and neutral detergent fiber (NDF) by 7 to 40 percent.
Continue reading this article published in Feed Strategy.
