EFFECT OF SUPPLEMENTING DRY YEAST OR BENTONITE AND THEIR COMBINATION AS FEED ADDITIVES ON GROWTH PERFORMANCE OF BUFFALO CALVES.

This study was conducted to investigate the effect of addition active dry yeast and bentonite or their mixture to buffalo calve rations on digestibility, rumen parameters, blood metabolites and growth performance. Total of twelve healthy growing buffalo calves with an average body weight of 290.83±11.90 Kg and aged thirteen months old were used in a feeding trial lasted for 4 months as an experimental period using randomized complete block animals design and were fed individually according to Kearl requirements (1982), where 60% of their energy requirement as total digestible nutrients (TDN) was offered from concentrate feed mixture (CFM), while the other 40% of energy requirement was covered from Egyptian berseem (Br). An extra rice straw (RS) was offered as 0.5% of animal's body weight (control ration). Animals were divided randomly into four groups (three animals per group) as follows: T1 (control ration), (T2) control ration plus yeast (10 g /animal /day), (T3) control ration plus bentonite (20 g/kg DM intake),(T4) control ration plus bentonite (20 g/kg DM intake plus yeast (10g/animal/day. The digestibility of CF, EE and NFE as well as the feeding values as TDN and DCP were almost had the same trend of DM digestibility among dietary treatments. Results of rumen parameters showed no clear trend among the dietary treatments respecting NH3-N concentration, however, almost its values of the tested rations were higher by difference degrees than that of control one. While the concentrations of TVFAs were significant higher with bentonite or yeast/bentonite rations than that of control or yeast – rations. No statistically significant differences were observed among the experimental rations for all measured blood metabolites, except that of urea-N was significantly (p<0.05) lower in group T3 and insignificant lower in groups T2 & T3 than control. Performance of calves in terms of daily gain, total dry matter intake did not affected by supplemented yeast and bentonite or both of them to rations. While, there were significant(p<0.05) differences between experimental rations in feed conversion as DM and TDN intake per kg gain where the best feed conversion was associated with rations supplemented by bentonite and their mixture with yeast (T3 and T4). Similarly the beast economical efficiency was occurred with the rations (T3 and T4). Generally, from the obtained results could be concluded that the supplementation of dry yeast and bentonite or both of them to rations of buffalo calves had positive effects on digestibility, feeding value, and some rumen parameters growth performance and economic efficiency