The effect of roughage and urea solution infusion levels on ruminal NH3-N concentration and nutrient digestibility in beef cattle and swamp buffaloes.

Abstract

Four, fistulated, male crossbred cattle and swamp buffaloes were randomly assigned in a 2 x 2 factorial arrangement in a 4 x 4 Latin square design. There were four combination dietary treatments; T1) UTS as a roughage and urea infusion at 50 g/h/d (50U), T2) UTS as a roughage and urea infusion at 100 g/h/d (100U), T3) CH as a roughage and urea infusion at 50 g/h/d (50U) and T4) CH as a roughage and urea infusion at 100 g/h/d (100U). Rumen fluid and blood were collected at 0, 0.5, 1, 1.5, 2, 3, 4 and 6 h-post feeding and then analyzed for total bacteria and protozoal, NH3-N, VFA and BUN, respectively. It was found that TDMI in buffoloes fed with UTS as a roughage source with both urea solution infusion were highest (P<0.05). While, digestibility of OM was higher in cattle fed with UTS as a roughage and urea solution infusion in both levels, CP, NDF and ADF digestibility were affected by type of roughage (P<0.05). With regards to digestible nutrient intake, the values of OM, CP, NDF and ADF (kg/d) were significantly different among treatments (P<0.05). Higher levels of ruminal pH were found in buffaloes fed with CH as a roughage and urea infusion in both levels (P<0.05). NH3-N concentrations were higher (P<0.05) in buffaloes fed with CH as a roughage and urea in fusion at 100 g/h/d (34.3 mg%) and lower in cattle fed with both roughage sources and urea infusion at 50 g/h/d (20.0 and 23.5 mg%, respectively). TVFA was affected by type of roughage (P<0.05) and urea infusion at 100 g/h/d. Proportion of C2, C3 and C4 were significantly different (P<0.05) among treatments.