Authors : M.R. Dehghani, K. Rezayazdi, M. Dehghan-Banadaky and H. Mansoori
Abstract: The aim of this experiment was to study the effect of fibrolytic enzyme on milk yield and composition, rumen microbial count and pH and blood metabolites of fifteen multiparous lactating cows (DIM 30±10 days). The experimental diets include: Control (based diet with no enzyme), basal diet with 2.5 g enzyme/kg of DM and basal diet with 5 g enzyme/kg of DM. Change-over design were used with three period, three treatments and five cows allocated to each diet. Individual dry matter intake and milk yield daily recorded and milk samples were taken for milk constituents analyze in each period. Rumen fluid collected for determining of pH and microbial count from each cow in every period at 0 and 4 h after feeding. Results indicated that low level of enzyme (2.5 g kg-1 of DM) increased milk production and 3.5% FCM compared to the other groups (p≤0.05). However, milk compositions were not affected by enzyme. Cows consuming high level of enzyme (5 g kg-1 of DM) had higher dry matter intake compared to the other groups (p≤0.01). Cows consuming high level enzyme had significantly lower milk efficiency compared to the other groups (p≤0.05). Enzyme had no effect on rumen pH and microbial (bacteria and protozoa) growth at 0 and 4 h after morning feeding. Furthermore, diet with low level enzyme increased plasma glucose concentration of dairy cows (p≤0.05). Results showed that low level of enzyme (2.5 g kg-1 of DM) can be recommended in the diet of early lactation Holstein cows.
M.R. Dehghani, K. Rezayazdi, M. Dehghan-Banadaky and H. Mansoori, 2011. Effects of Fibrolytic Enzyme on Milk Yield, Blood Metabolites, Rumen Microbial Growth and pH of Holstein Cows in Early Lactation. Journal of Animal and Veterinary Advances, 10: 3048-3052.