RESUMEN
The effects of long-term feeding of wood kraft pulp (KP) silage containing sweet-potato shochu distillery by-product (SDP) on feed intake, feed digestibility, rumen fermentation, and growth performance of Japanese Black steers were investigated during the early fattening period. Ten Japanese Black steers (9.8 ± 0.6 months of age) were used in this study. Five steers (KP group) were fed KP silage as a replacement for 10% timothy hay (dry matter bases), in contrast to the other five (control group). KP silage consisted of 92.9% KP and 7.1% SDP (dry matter bases). The experiment was conducted for 18 weeks. No significant differences were observed in terms of feed intake, feed digestibility, or daily body weight gain between the groups. In addition, diurnal changes in the rumen pH and ruminal lipopolysaccharide activity did not differ between the groups. However, the plasma concentration of aspartate transaminase in the KP group was slightly lower (P = 0.078) than that in the control group. Thus, our study suggested that feeding KP silage does not reduce feed intake or affect the rumen fermentation or growth performance of Japanese Black fattening steer.