The effect of fibrolytic enzyme supplementation on protozoal populations in beef cattle fed high grain diets

The pre-feeding addition of fibrolytic enzyme products to high grain diets fed to dairy cows has been shown to modify microbial populations in the rumen (Nsereko et al. 2002). Four Bos indicus steers (mean 314 kg, s.d. 26 kg) were allocated per treatment to either barley or sorghum grain-based diets (approx. 60% dry-rolled grain, 27% Pangola grass chaff, 10% cottonseed meal + supplements) with 1 of 2 levels (0 or 13200 IU Xylanase/kg diet DM) of a Trichoderma longibractiatum-derived enzyme complex, Roxazyme® G2 Liquid (RG2; F.Hoffmann-La Roche AG, Basel, Switzerland). The RG2 was applied to the grain portion of the concentrate mix at least 24 h before feeding. The steers were fed ad libitum such that all the chaff and half of the daily concentrate allocation was offered at 0800 h and the other half of the concentrate mix was fed at 1400 h.