Effect of herbal feed additives rich in tannins on rumen fermentation pattern, enteric methane emission and performance of buffalo calves

The effect of tannin rich herbs supplemented to a total mixed ration (TMR) was assessed on the rumen fermentation pattern, enteric methane emission and performance of buffalo calves. Fifteen calves (live body weight 96.5±2.5 kg) divided into three equal groups were fed control TMR or TMR supplemented with Acacia nilotica (Babul) or Areca catechu (Supari) at 2% of DM intake for 180 days. Data were analyzed by one-way ANOVA, while that of enteric methane emission by 3×2 factorial design. The nutrient digestibility, nitrogen retention, volatile fatty acids (VFAs) production; urinary excretion of purine derivatives (PDs), blood profile and average daily gain (ADG) were not affected, thereby indicating that these herbal feed additives (HFAs) had no negative impact on the nutrient utilization. The efficiency of rumen fermentation (E) was improved, while that with which the fermented hexose is converted to methane (E₂) was reduced significantly in animals fed TMR supplemented with A. nilotica as compared to those fed control TMR or that supplemented with A. catechu. The enteric methane emission was reduced (P<0.01) by 38.8 and 42.9% in animals fed TMR supplemented with A. nilotica and A. catechu as compared to the control TMR. It was concluded that supplementing TMR with Acacia nilotica or Areca catechu at 2% of DM intake reduced enteric methane production without affecting the nutrient utilization and performance of buffaloes calves.