2000 Volume 71 Issue 10 Pages 475-482
Two experiments were undertaken to determine the effect of ruminal dosing of mechanical stimulating brush (RF) for the mucosa in the rumen on the rumination time and rumen fermentation status. The rumination behavior under field flock in experiment 1 (8 heads) and rumination behavior and rumen fermentation status under individual feeding in experiment 2 (8 heads) were investigated under high concentrate diets (organic cell wall contents: 27.5% DM) using Holstein steers (16 heads). The experimental animals were orally administered the RF (three RF per head) at 12 month of age in experiment 1 and 8 month of age in experiment 2 as a RF treatment (4 heads), and the non-administration was made as control (4 heads) in both experiments. Grass hay was fed to the animals (0.2kg/head) at 19 month of age, and was not fed later in experiment 1 and concentrate was given ad libitum in. Concentrate was fed to the animals as a sole diet in experiment 2; and was fed to suffice 1.0kg daily gain. The observation of rumination behavior was carried out at 14 month of age (average weight 513kg), 17 month of age (616kg) and 20 month of age (696kg) in experiment 1. The observation of rumination behavior and the investigation of rumen fermentation status were carried out at 18 month of age (average weight 696kg) in experiment 2. In experiment 1, there was no statistical difference (P>0.05) for feed intake between the RF treatment and the control. The rumination time per day for the animals in the RF treatment was longer (P<0.05) than that in the control group. In experiment 2, the feed intake per day was greater (P<0.05) for the RF group than for the control. The rumination time per day and per DM intake for the animals in RF treatment was longer (P<0.05) than that in control group. The ruminal VFA concentration was greater for the RF group than the control for 6 to 12h post morning feeding. With it, the ruminal pH for the animals in RF treatment tended to be lower than that in control group, but the pH value before morning feeding did not differ statistically (P>0.05) between the RF treatment and the control. The ratio of acetic acid to propionic acid for RF group was lower than that in control group. From the above result, it is supposed that RF affected the mucosa in the rumen as a physical stimulus under high concentrate diets, and it is suggested that there was the possibility of lengthening mastication time of rumination per day by the induction of the regurgitation of a bolus.
