Effect of isobutyrate supplementation on rumen fermentation and nutrient utilization in cattle fed urea impregnated wheat straw

Abstract

Eight crossbred rumen fistulated male cattle (2-31/2 years, 240-242.75) were divided into 2 similar groups and fed wheat straw, aground maize (CP 10%) and sodium sulphate to attain N:S ratio of 10:1 (group 1) or supplemented with sodium isobutyrate to provide isobutyric acid @ 0.75% of the total DMI (group 2). Though the total 1 and the average values were 89.48 and 100.30g/100kg b.wt. in groups 1 and 2 respectively. Digestibility coefficients of DM, OM, EE, CF, NEE, NDF, ADF, hemicellulose and cellulose were not affected, whereas CP disgestibility was improved (P<0.05) by. 7.95% on addition of isobutyrate. Nitrogen balance was 8.94 and 20.10g/day showing an improvement (P<0.05) of 124.83% in grouop 2 over that of control. Ruminal total N, NH3-N, NPN-N and TCA precipitable N. TVFA concentration and proportion of acetate. Propionate and butyrate were not affected by the dietary tratments. Branched chain fatty acids viz. isobutyrate, 2 methyl butyrate and isovalerate concentration were significantly higher in group 2 than in group 1. Ruminal fluid volume and flow rate of liquid digesta was 31.34 and 35.02:68.88 and 74.88 liters/day which was significantly higher (P>0.05) in group 2 than in group 1.  Thus the results indicated an improvement in nitrogen utilization of ura enriched wheat straw in cattle on dietary supplementation of isobutyric acid.