The lactational response of dairy cows fed fiber-degrading enzymes has been scarce and inconsistent. The effectiveness of fiber-degrading enzymes to improve milk production has only been observed in 30 percent of studies; however, eight experiments showed positive results.
Based on the experiments included in this literature review, the average increase in milk yield due to the enzyme addition was 5.5 lbs./day (2.6 to 13.9 lbs./ day); none of these experiments reported reduction in milk yield when the cows were fed fiber-degrading enzymes. The response, however, was highly dependent on enzyme dosage, enzyme combination and the method of enzyme application to the diets.
Low dosages yield positive results
University of Delaware researchers studied the effect of a carboxymethyl cellulase (CMC) and xylanase complex at two different concentrations on milk production in lactating cows.
Surprisingly, the authors reported that enzyme treatment at low, 1,600 CMC and 7,300 xylanase units per pound of forage dry matter (DM), but not high, 4,000 CMC units and 18,200 xylanase units, concentrations improved milk production by 6.8 percent.
Similarly, supplementing a fiber-degrading enzyme mixture enhanced milk production by 3.2 percent at a low dosage rate (1.2 g/lbs of DM) in early lactating cows, but not at a higher concentration (2.3 g/pound of DM) in another study.
Continue reading this article published in Feed Strategy.
