Effect of concentrate to roughage ratio and bakers yeast supplementation during hot season on performance of lactating buffaloes

Sixteen lactating buffaloes after 8 weeks of calving in the 2nd to the 5th lactating season, weighing 500 to 600 kg during summer season were used in a complete switch–back design (Lucas, 1956) with four groups and three successive experimentation periods. Buffaloes in the first and the second group were fed ration consisting of 60% concentrate feed mixture and 40% roughages (berseem hay and rice straw) without (G1) or with 15 g bakers yeast (Saccharomyces cerevisiae)/head/day (G2) on DM basis. While those in the third and the fourth group were fed ration consisting of 40% concentrate feed mixture and 60% roughages on DM basis (berseem hay and rice straw) without (G3) or with 15 g bakers yeast/head/day (G4). Obtained results showed that the contents of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE) and nitrogen free extract (NFE) tended to increase; their digestibilities and total digestible nutrients (TDN) and digestible crude pro­tein (DCP) values increased significantly (P less than 0.05), however, the contents of CF and ash tended to decrease and CF digestibility decreased significantly (P less than 0.05) with increasing level of concentrate and decreasing roughages level. The digestibilities of all nutrients and nutritive values increased significantly (P less than 0.05) with barkers yeast supplementation. The intake of DM, TDN and DCP increased significantly (P less than 0.05) with increasing level of concentrate and decreasing roughages level. The intake of TDN and DCP increased significantly (P less than 0.05) with bakers yeast supplementation. Ruminal pH value decreased significantly (P less than 0.05), while ruminal total volatile fatty acids (TVFAs) and ammoniacal nitrogen (NH3-N) concentrations increased significantly (P less than 0.05) with increasing level of concentrate. However, ruminal pH value and NH3-Nconcentration decreased significantly (P less than 0.05) and TVFAs concentration increased significantly (P less than 0.05) with bakers yeast supple­mentation. The yield of actual milk increased significantly (P less than 0.05) with increasing level of concentrate, while the yield of 7% fat corrected milk (FCM) increased significantly (P less than 0.05) with increasing level of concentrate as well as with bakers yeast supple­mentation. The contents of protein, lactose and SNF increased significantly (P less than 0.05), however, fat content decreased significantly with increasing level of concentrate and decreasing level of roughages. The contents of all milk constituents except ash increased significantly (P less than 0.05) with bakers yeast supplementation. The amounts of DM, TDN and DCP per kg 7% FCM increased significantly (P less than 0.05) with increasing level of concentrate and decreasing level of roughages in the rations as well as with bakers yeast supplementation. The average daily feed cost and feed cost per kg 7% FCM increased significantly (P less than 0.05), however, economic efficiency decreased significantly (P less than 0.05) with increas­ing level of concentrate and decreasing level of roughages in the rations. Average daily feed cost tended to increase, but the output of 7% FCM and economic efficiency increased significantly (P less than 0.05), while feed cost per kg 7% FCM decreased significantly (P less than 0.05) with bakers yeast supplementation. It could be concluded that lactating buffaloes fed ration consisted of 40% concentrate feed mixture and 60% roughages (berseem hay and rice straw) with 15 g bakers yeast supplementation/head/day on DM basis (G4) showed the best results concerning milk yield, feed conversion and economic efficiency.