Animal Nutrition and Feed Technology

Four rumen-fistulated crossbred steers were used in a crossover design to evaluate the effect of supplementing multi-nutrient blocks containing fermented Opuntia ficus indica on ruminal microorganisms population, intake and apparent digestibility of nutrients and ruminal fermentation. The steers were fed on ad libitum oat straw alone as a control (CON) or along with a supplemental multi-nutrients block containing fermented Opuntia ficus-indica (MNB). Steers were adapted to the respective diets for 15 d followed by a 6-d collection period. The blocks remained available to the animals round the clock. The results indicated that the populations of the total-and cellulolytic-bacteria were significantly higher in the MNB group of steers supplemented with multi-nutrient blocks containing fermented O. ficus-indica (P<0.05). Total intake of DM, OM, CP and NDF increased significantly by supplementation (P<0.05). Similarly, digestion rate (Kd), passage rate (Kp) as well as apparent digestibility of DM, OM, PC and NDF were increased (P<0.05) with the MNB supplementation. While there was no effect of MNB evident on the ruminal pH (P>0.05), the concentrations of ammonia nitrogen, total volatile fatty acids, propionate and butyrate increased with the supplementation (P<0.05). Thus, multi-nutrients blocks containing fermented O. ficus-indica can be used as a supplementary feed source when oat straw or others low nutritional quality roughages are fed to beef cattle.