Effect of doses of direct-fed microbials plus exogenous fibrolytic enzymes supplementation on growth, feed efficiency ratio and fecal consistency index of brown swiss and holstein Friesian Calves

The objectives of this study were to compare the effect of different doses of direct-fed microbials (DFM) plus exogenous fibrolytic enzymes (EKE) additives on the growth performance, feed efficiency ratio and fecal consistency index of Brown Swiss and Holstein Friesian calves. Twenty six calves were assigned to three groups (control, 10 g and 20 g per head/day of DFM plus EFE) according to breeds. Calves in 10 g per head/day of DFM plus EFE group in pre- and post-weaning periods had 20.0 % and 6.3 % higher total weight gains than calves in the control group respectively. However, the effects of breeds and dosages of the supplement on the weights, weight gains and feed efficiency ratios were not significant. Average fecal consistency score of the calves fed a diet supplemented with 10 g head/day of DFM plus EFE had the lowest score (P<0.01) (i.e., less scouring) compared to other treatment groups in pre-weaning period as well as between birth and 6 months of age. The study revealed that the feeding of DFM plus EFE to dairy calves until 6 months of age did not result in statistically significant improvement on the growth traits and feed efficiency ratio. On the other hand, the dose of 10 g head/day of the DFM plus EFE, additives might be beneficial for reducing incidence of diarrhea in dairy calves.