Abstract
This experiment was conducted to determine the effects of ruminal dosing of mechanical stimulating brush (RF) on chewing activity, ruminal contraction, ruminal passage rate on liquid and solid phases and ruminal fermentation status in steer fed high concentrate diet. Three Holstein steers (average weight : 519kg) fitted with rumen fistula were used as experimental animals. All animals were fed enough to meet their required metabolizable energy on 2 × the maintenance level with timothy hay cut at 10cm length as roughage, and rolled barley and soybean meal as concentrate. The experimental diet had a ratio of 1 : 9 roughage and concentrate, and fed twice daily in equal portion at 10 : 00am and 05 : 00pm. Two treatments were set up, non-dosing (Control) and dosing of RF (RF-dosing). Steers were dosed with three RF per head through the rumen fistula. The following results were obtained : 1) RF-dosing enhanced the increase of rumination time significantly (P<0.05). Moreover, the frequency of ruminal contraction tended to increase in RF-dosing (P<0.10) (1,463 and 1,968 times/day in control and RF-dosing, respectively). 2) The ruminal passage rate on both liquid phase and solid phase (P<0.05 and P<0.10, respectively). 3) RF-dosing had no effect on pH and volatile fatty acid concentration and its composition in rumen liquor. These results suggested that the increase in rumination time would have a connection with the frequency of ruminal contraction increased on Holstein steers dosed with RF. Also, it was suggested that saliva secreted with rumination caused to increase ruminal passage rate on liquid phase.
