Effect of Adding a Cell Wall Degrading Enzyme to a Total Mixed Ration for Lactating Cows

Abstract

The objective of this study was to examine the effects of an enzyme additive containing cellulase and xylanase enzymes in a total mixed ration (TMR) for lactating cows. Multiparous Holsteins were used in a 52-d trial from August to October, 1994. Treatments were control (no additive) and enzyme additive (Rumenase®). Both groups (approximately 85 cows per pen) were fed a TMR composed of alfalfa hay; corn silage, beet pulp, whole cottonseed, rolled barley, rolled corn, molasses supplement, protein pellet, and condensed whey. Cows on the enzyme additive treatment received in their TMR, 1.7L of enzyme concentrate per tonne of TMR forage DM. The enzyme concentrate was diluted with 946L of water and sprayed on the TMR before the mix was offered to the treatment pen. Daily milk production for cows that entered the trial less than or equal to 40 DIM was significantly higher (P<0.01) for the group fed the enzyme-treated TMR (43.9 vs 43.0 kg/d). No differences were detected for cows that entered the trial at more than 40 DIM. Cows supplemented with the enzyme additive had significantly higher plasma urea N concentrations than control cows (18.1 vs 15.0 mg/100 mg). Apparent digestibilities of DM, CP, ADF, or NDF were not different between control and enzyme additive groups. The application of a commercial enzyme mixture to a TMR may increase milk production in early lactation.