The Effects of Varying Proportion of Rubbed Bamboo Silage in Roughage Ration on Behavior and Meat Production Traits of Japanese Black Steers in the Late Fattening Period

<p>The objective of this study was to clarify the effects of feeding rubbed bamboo silage (RBS) instead of rice straw (RS) as roughage for beef cattle at the late fattening stage. Twelve Japanese Black steers (20 months old) were divided into three groups: the first group was fed on 100% RS as roughage (control group); the second and third groups were fed on blended RBS and RS as roughage (representing 70% or 85% of the crude fiber contained in the control group’s RS ration; RBS 70% group and RBS 85% group, respectively). All groups were slaughtered at 28 months of age. The growth, behavior, ruminal pH and carcass traits were investigated. Although the rumination behavior of the RBS 70% group and the RBS 85% group decreased significantly at 21 months of age (P < 0.05), no significant differences were observed in body weight during the experimental period. There were no significant differences in roughage value index (RVI) between the groups. The ruminal pH value of the RBS 70% group was significantly lower than that of the other groups at 27 months of age (P < 0.05), but the value was not indicative of clinical abnormality. The carcass characteristics of the RBS 70% group and the RBS 85% group were comparable to those of the control group. In conclusion, RBS is an acceptable alternative roughage to RS at the 85% level after 20 months of age in terms of meat productivity.</p>