Abstract
The objective of this study was to compare the influence of grinding and/or urea-treatment of rice straw on fiber utilization in cattle and buffalo, Rumen-fistulated beef and buffalo steers were fed rations containmg. native rice straw, ground rice straw or urea-treated, ground rice straw and apparent fiber digestibility and rumen fluid characteristics were measured. Group-mean intake of roughage was enhanced in the beef steers fed urea-treated, ground rice straw but this was not seen in the buffaloes. Group-mean apparent digestibility of neutral and acid detergent fiber was raised by the feeding of urea-treated, ground rice straw versus ground rice straw in cattle, In the buffaloes, group-mean fiber digestibility was higher for urea-treated, ground rice straw than for native or ground rice straw. The apparent digestibility of crude protein was systematically lower in buffalo than in cattle. There was no effect of type of roughage on ruminal pH but the values were lower in buffalo than in cattle. Group-mean ruminal ammonia concentrations were higher in buffalo than in beef steers. The ruminal concentrations of acetate and propionate were significantly lower in. buffalo than in. cattle but the group-mean concentrations of butyrate were higher. The numbers of cellulolytic and amylolytic bacteria were markedly lower in the rumen fluid from buffalo than cattle. It is concluded that the present data do not allow a straightforward conclusion as to treatment of rice straw improving its utilization more in cattle or buffalo.