The effect of wheat bran supplement to rice straw diet on the ruminating behavior in sheep was investigated, using two rumen-fistulated adult wethers (49.5 and 36.5kg of B. W.).
In each of two experimental periods, wethers were given 600g of rice straw daily either alone or with 200g of supplementary wheat bran. In each period, following 7-day preliminary feeding, eating and ruminating behaviors were measured for seven consecutive days. In addition, chemical conditions within the rumen and digestibility of the rice straw were measured.
Wethers ate the rice straw more rapidly when wheat bran was supplemented than when rice straw diet alone was fed. The mean time spent in ruminating reduced significantly in one wether but not changed in the other wether when wheat bran was supplemented. However, the chewing time in each bolus or the cyclic rate of regurgitation shortened significantly in both wethers due to supplementary wheat bran. Furthermore, supplement of wheat bran clearly reduced the rumen pH and increased the VFA and ammonia concentrations within the rumen, and resulted in significantly greater digestibility of each component in the rice straw as compared to the feeding of rice straw alone.
It is suggested that wheat bran supplemented to rice straw diet has some effects upon the ruminating behavior in relation to the change of ruminal fermentation.