Feed intake, digestibility, plane of nutrition and live weight gain by crossbred growing bulls fed on grainless diets containing different nitrogen sources

Abstract

Twenty five growing crossbred bulls (Bos indicus×Bos taurus) were used in a randomised block design experiment for 196 days to determine the effect of grainless concentrate containing different supplemental nitrogen sources along with wheat straw based diet on feed intake, nutrient digestibility, plane of nutrition and daily live weight gain. The animals in control group received barley 30% in the concentrate mixture (Cm1) as a source of grain, where as other concentrate mixtures contained only wheat bran (Cm2) or wheat bran supplemented with 2.5% urea (Cm3), 21.5% groundnut oil cake (Cm4) or 27% mustard oil cake (Cm5) as source of supplemental nitrogen. Fortnightly live weight gain was recorded and a metabolism trial of 6 days duration was conducted after 120 days of feeding trial in order to assess nutrient utilisation and retention as well as plane of nutrition. The mean dry matter (DM) intake and digestibility of the nutrients except crude protein (CP) were similar in all the groups. CP digestibility was significantly higher (P<0.05) in urea fed animals. A positive nitrogen balance was recorded in all the groups. Though gross energy (GE) and digestible energy (DE) intake were not affected, the urinary loss of energy (UE) was significantly lower (P<0.05) in animals fed Cm2. A positive calcium and phosphorus balance was observed in all the treatments though phosphorus balance in Cm2 fed animals was significantly higher (P<0.05). Average daily live weight gains were 443, 344, 370, 435 and 423 g in Cm1, Cm2, Cm3, Cm4 and Cm5 fed animals, respectively. A marginal less daily live weight gain was recorded in Cm2 fed animals and the results were non-significant among the treatments. Active growth could be obtained in animals fed grainless concentrates having wheat bran as its main component at an amount of 1% of the live weight daily without showing significant influence on nutritional status and growth of growing bulls.