In order to study the effect of nursing on the grazing behaviors, two groups of Japanese Black Breed of cattle, 2 prime cows (4-9 years old), 2 prime nursing cows (6-8years old) were used in this study under constant observation on pasture for 24 hours in May 26 to 29, 1963. The results obtained are summarized as follows :
1 . The grazing time on pasture per head for 24 hours was 428 minutes in prime cow and 425 minutes in prime nursing cow.
The grazing time in day-time was longer than that at night in both groups.
2 . The ruminating time on pasture for 24 hours per head was 383 minutes in prime cow and 479 minutes in prime nursing cow.
The ruminating time at night was longer than that in day-time in both groups and the ratio of ruminating time to grazing time was higher in the nursing group than in the not-nursing one.
3 . The resting time on pasture per head for 24 hours was 545 minutes in prime cow and 435 minutes in prime nursing cow.
The resting time in day-time was longer than that at night in both groups.
4 . The total time spent in migrating and loafing on pasture for 24 hours per head was 84 minutes in prime cow and 80 minutes in prime nursing cow.
5 . The frequency of defecation, urination and drinking per head per day showed a similarity in both groups.
6 . The distance walked on pasture per head for 24 hours was 4.4 km in prime cow and 5.6 km in prime nursing cow.
7 . The grazing time of wild grass per head for 24 hours was higher than that of pasture grass in both groups.