effect of diets containing urea molasses on the fattening performance and blood urea nitrogen of arabia male lambs.

in order to investigate the effect of diets contained urea and molasses on fattening performance and blood urea nitrogen (bun) density of male lambs, 72 arabic male lambs were used in a completely randomized design with a 3×4 factorial experiment, for 90 days. the experimental diets contained; 0, 0.5, 1 and 1.5% of urea each with 0, 7.5 and 15% of molasses, in isoprotein and isocalaric diets. the diets were prepared as total mixed ration and fed ad libitum twice per day.  results showed that the highest and lowest average daily gain (adg) of lambs were obtained in lambs received  diets contained 0.0 and 1.5% urea, respectively (p < 0.05). utilization of different levels of molasses did not significantly affected the  adg of lambs. the lambs  adg was not affected by the interaction of urea and molasses in the diets. however, dry matter intake (dmi) and feed conversion ratio were affected by different levels of urea or molasses, and interaction of urea×molasses (p < 0.05). the highest and lowest concentration of  bun were detected in lambs received diets contained 1.5% and 0.5% urea with 29.42 mg/dl and 26.78 mg/dl respectively (p < 0.05). bun density was not affected by molasses level, but it was affected by the interaction of urea×molasses in the diet (p < 0.05). in general, based on the results of this experiment, utilization of 1.5% of urea plus 7.5% of molasses in the diet of fattening lambs, could reduced the feed cost and improve the optimization of fattening lambs performance.