Level and Form of Rice Straw in Steer Rations

Two feedlot trials were conducted to study the performance of steers fed rations containing different levels, forms and grinding screen size of rice straw. Steers receiving 20% ground rice straw consumed more concentrate and gained faster resulting in heavier carcasses than steers fed 20% pelleted or long rice straw or 5% ground, pelleted or long rice straw (P<.05). There was no significant differences in the concentrate intake, gains or carcass weight of steers fed 5% rice straw in any form or long or pelleted rice straw fed at the 20% level. The performance of steers fed 5% rice straw and all-concentrate rations was similar. The size of the grinding screen had no significant influence on performance of steers fed 5 or 20% rice straw rations. Molasses levels of 10 or 25% did not appear to influence gain or carcass weight but feed efficiency was slightly decreased when 25% molasses was included in the 20% rice straw ration. Ruminal fluid from steers fed 20% ground rice straw was higher in acetate and lower in propionate for steers fed 5% rice straw or all-concentrate rations. There was very little difference in ruminal fluid due to the grinding screen size or molasses level.