Abstract
This experiment was carried out to examine the effect of feed utilization and rumen characteristics by the ruminal dosing of mechanical stimulating brush (RF) in Holstein steer fed mainly rolled barley. Four Holstein steers (602 kg in average body weight) fitted with rumen fistula were used. All steers were fed enough to gain 1.2 kg/day in body weight with 10 cm long timothy hay in roughage, rolled barley and soybean meal in concentrate. The ration had a ratio of 7 : 93 roughage and concentrate, and fed 2 times in equal amount at 0900 and 1600. Three RF per head were put into the rumen. Two treatments were set up according to dose, non-dosing (Control) and RF-dosing. The results are as follows. 1) Digestibility and total digestible nutrients was not significantly different between both treatments. 2) N excretion in urine was lower in RF-dosing than in control (P<0.05). Therefore, N retention increased by RF-dosing (P<0.05). 3) Energy loss in methane was lower in RF-dosing than in control (P<0.05). However energy retention was not significantly different between both treatments. 4) RF-dosing had no effect on pH of rumen liquor. Ammonia-N and volatile fatty acids concentration of rumen liquor in RF dosing were lower than those in control. And RF-dosing decreased on molar proportion of acetic acid and increased on molar proportion of propionic acid and butyric acid. 5) Passage rate of liquid and solid phase through rumen increased (P<0.05) when steer was dosed RF. Thus efficiency of feed utilization is improved by control of nitrogen and methane excretion when Holstein steer fed mainly rolled barley were RF dosed.
