Effect of Different Levels of Direct-fed Microbials Plus Exogenous Fibrolytic Enzymes Additives on the Growth Traits of Dairy Calves

The study was carried out to investigate to determine effects of the different levels of the direct-fed microbials (DFM) plus exogenous feed enzymes (EFE) on the body weights, weight gains, feed efficiency ratio, some behavioral traits as well as fecal consistency index of male Brown Swiss calves. For this purpose, 18 male Brown Swiss calves were allocated to three groups (control, 10 g and 20 g head/day of DFM plus EFE). Weights obtained at weaning time and 6 months of age of the calves in 10 g head/day of DFM plus EFE group were respectively 7.3% and 7.1% heavier than these of animals in control group. The calves in 10 g head/day of DFM plus EFE group in pre-weaning and between birth and 6 months of age periods also had respectively 16.0% and 7.3% higher total weight gains than calves in the control group. Feed efficiency ratio of the calves fed diets with 10 g DFM plus EFE had 64.2% better than that of calves in control group. 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