McAllister et al. (2001)) noted tha

McAllister et al. (2001)) noted that the inconsistency in research results from trials with enzyme supplementation is in part related to the indiscriminate use of enzymes on different types of forages or feedstuffs without targeting specific substrates, which results from a lack of understanding of the structural tissue organization and composition within each type of grain or forage. Ultimately, enzyme cocktails should be specifically designed to overcome the constraints limiting digestion of a particular type of feed. Component enzymes in such cocktails might vary even for a given forage, targeting particular maturity stages and structural barriers (McAllister et al., 2001). Moreover, comparisons between experiments are exceedingly difficult to make because many enzyme products are poorly defined in the published papers (McAllister et al., 2001).