牧草地におけるヘレフォード種子付成雌牛の放牧行動について

The grazing behaviours of three Hereford nursing cows on the mixture sawing pasture were studied over continuous periods of 24 hours in late August in Hokkaido. Furthermore, the differences between the behaviours of the Hereford cow and the Japanese Black Breed cow were examined. The weather of the first day of investigation was rainy and was struck by a typhoon, but the second day was fine.
The results obtained were summarized as follows :
1. The weather and the pasture condition had no influences on the hours spent in the principal behaviours. However, there was a marked tendency that the hours spent in lying down were longer than those spent in standing on the fine day in contrast with on the rainy day.
2. Hereford cow spent approximately 8 hours in grazing and 9 hours in ruminating. These hours spent in grazing and ruminating were distinctly longer than those of the Japanese Black Breed cow. Hours spent in resting of the Hereford cow were about 5 hours and were shorter than those of the Japanese Black Breed cow.
3. The distance walked within 24 hours was 6.05 km. on the average, and it was longer than that of the Japanese Black Breed cow.
4. The peak of grazing within 24 hours was observed three times in the daytime and once in the night. These aspects were almost the same with the Japanese Black Breed cow.
5. The average number of boli regurgitated within 24 hours was about 750, and it was 50% more than that of the Japanese Black Breed cow. The average rate of chewing was 66 times/min., and it was more speedy than that of the Japanese Black Breed cow.
6. The Hereford cow spent 85% of the grazing hours for the grazing of pasture grass and 15% for native-grass. This tendency was in marked contrast to the case of the Japanese Black Breed cow. (native-grass : 54%)
7. These results obtained indicate that the Hereford cow spent more hours in grazing and ruminating, walked longer distance and prefered the pasture-grass to the nativegrass as compared with the Japanese Black Breed cow. It is evident that the Hereford cow is the more suitable breed for grazing on pasture-grass than the Japanese Black Breed cow.