Evaluation of additive effect of feed additives in crossbred cows under in vitro and in vivo conditions

Abstract

The Study was conducted to evaluate the additive effect of selected feed additives (Glycerol, a mixture of exogenous fibrolytic enzymes (EFE), a mixture of probiotics and rumen protected methionine (RPM) under both in vitro and in vivo conditions. The optimum dose of pre-mixture of feed additives (PFA) was evaluated by in vitro gas production technique in two stages. The marginal increase in Y-max and in vitro neutral detergent fiber digestibility (IVNDFD) for each incremental increase in PFA was compared graphically and it was found to be 1.7 %. In in vivo trial, 12 crossbred HF cows were equally divided into 3 groups based on milk yield and average days in lactation. The optimized dose of PFA was added to the concentrate supplements without (T1) or with buffer (T2), control group (CG) was fed with the basal diet (roughage: concentrate ratio of 60:40). Results indicated that PFA with or without buffer had no significant effect on nutrient intake and digestibility. Fat corrected milk yield (FCM), milk fat, total solids (TS) and milk protein were significantly (P Lass Than 0.01) increased in TGs than that of CG. From the results, it may be concluded that optimized PFA had an additive effect on milk production efficiency but not on nutrient intake and digestibility. Further, different groups of feed additives can be evaluated for additive effect, which may pave the way for commercial product preparation.