放牧牛の生理・生態に関する研究(I-4) : 改良牧野における放牧和牛の行動について

抄録・要旨

The effects of age and nursing on the grazing behaviors of pasturing cattle have been studied and compared with those of range cattle previously reported.
The following three groups of Japanese Black Breed of Cattle were used : 3 heifers (18-21 months old), 3 prime cows (3-5 years old) and 3 prime nursing cows (4-6 years old).
The constant observation method for 24 hours was adopted for these investigations from Octobet 25 to November I, 1961.
The results obtained were summarized as follows :
1. Grazing time on pasture for 24 hours was 535 minutes in average per head in heifer, 668 minutes in prime cow and 641 minutes in prime nursing cow, respectively. Grazing time of the cow on pasture was longer than that of on range, but no distinct difference of the grazing time was found for 24 hours among each group of cattle.
2. Ruminating time on pasture for 24 hours was 269 minutes in average per head in heifer, 360 minutes in prime cow and 426 minutes in prime nursing cow, respectively. Lying time was longer than standing time in ruminating form on pasture, and the lying time at night was longer than that in day-time. This tendency was similar to that of the range cattle previously reported.
3. Resting time on pasture for 24 hours was 536 minutes in average per head in heifer, 346 minutes in prime cow and 330 minutes in prime nursing cow, respectively. Resting time on pasture was a little shorter than on range, but the ratio of standing time to lying time on pasture did not differ distinctly from the ratio on range.
4. The total time spent in migrating and loafing on pasture for 24 hours was 100 minutes per head in heifer, 67 minutes in prime cow and 41 minutes in prime nursing cow, respectively. A remarkable decrease of the total time on pasture was shown as compared, with that of on range.
5. The distance walked on pasture per head for 24 hours was 5.582km in average in heifer, 3.136km in prime cow and 3.382km in prime nursing cow, respectively. It seemed that the cattle grazed on pasture decrease remarkably their distance walked compared with that of on range.