The eating and rumination behaviour was investigated in sheep fed only a dried forage diet varying crude fibre content, and the following results were obtained.
1) The time spent eating the dried forage diet was clearly decreased with a decrease of dietary fibre content, and tnerefore, the rate of eating tended to increase with a decrease of dietary fibre content.
2) Daily time spent ruminating and the number of boli regurgitated were smaller in feeding of diet of low fibre content than in feeding of diet of high fibre content. The daily number of rumination periods was decreased with a decrease of dietary fibre content.
3) The number of chews per bolus and rumination chewing rate were fairly greater in feeding of high fibre diet than in feeding of low fibre diet. This result clearly shows that the rumination by sheep was more intensive and efficient when they were given the diet of high fibre content.