めん羊の反すう行動の日変異性について

The variations of ruminating activity on a constant feeding condition were investigated. With two adult sheep fed the same amount of good-quality Italian-ryegrass hay, the rumination behaviour was observed continuously during a 6-days period.
The activity of rumination in terms of time spent ruminating was not constant from day to day, ranging from 370 min. to 507 min. and 370 min. to 459 min. daily in each sheep. Although percent of time actually spent in chewing among ruminating time was not constnt in one sheep, there was a signifcant difference between the average in each sheep, as 72% compared with 81%. The average daily number of chews in rumination was approximately 30,000 and 24,000 respectively. The number of bouluses regurgitated daily was highly correlated to the time spent ruminating, with significant difference between sheep, but the number of chews per boulus tended to be same in both sheep and was constant on every day. In the average rate of chewing per minute, there was a large difference between sheep, i. e. 90.6 and 68.0 respectively, but little variance between days. The marked diurnal pattern in rumination was observed.