Nutrient intake, digestibility and rumen metabolites in bulls fed rice straw with or without supplements

Résumé

Nutrient intake, digestibility and rumen metabolites were determined in rumen - cannulated bulls fed rice straw or straw supplemented with urea, groundnut hay or cotton seed cake. Total dry matter intake (DMI) ranged from 7.55 10 8.29kg/d or 3.66 to 4.04% of liveweight and from 6.48 to 7.21kg/d for organic matter. Total DMI was increased by supplementation with urea and groundnut hay by about 7.6%. However, supplementation with groundnut hay and cotton seed cake reduced straw intake. Digestible organic matter intake (DOMI) was highest on straw supplemented with groundnut hay. There were no dietary differences in the digestibility of dry matter (DMD), organic matter (OMD), cellulose (CD) and hemicellulose (HCD). Digestibility of crude protein (CPD) was higher on the supplemented diets than on basal rice straw. The rumen pa ranged from 6.42 - 8.28; ammonia-N (RAN), 6.74 - 27.70mg/100ml; volatile fatty acids (VFA), 8.79 - 12.40mmol/100ml and bacterial count, 5.73-16.10 (x 10s)/ml and those values were affected by diets (D), period of sampling (P) and their interactions (D x P).