放牧牛の生理・生態に関する研究(II-15) : 舎飼時および春放牧中における和牛の工ネルギー消費について

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We studied on the energy expenditures of the Japanese Black Breed cows measured indirectly by the beatmeter method. Data obtained while the two cows were housed in the barn, grazed on the native grassland and housed again in the barn immediately after the grazing period.
The principal results obtained were as follows :
1. Daily energy expenditure per kilogram of body weight was about 12 Cal in average during the housing period before grazing. This value increased rapidly when the cows were put on the grassland, and reached at the maximum of about 35 Cal (280% of the initial value obtained in the barn) within the first one week. Then, the value decreased gradually to nealy 250%. After the grazing period was ended, it stayed at about 150% of the initial value, and it seemed that several days were necessary for it to recover to the initial value.
2. In any behavior the energy expenditure per kilogram per hour was about two times and one and a half times as much as the initial value in the barn, during the grazing period and immediately after it, respectively. Though the variations in energy expenditures per kilogram per hour was large in the walking forms, they were small in the resting ones.
3. When the grazing hours were the shorter, the energy expenditure per kilogram per hour were the grater ; consequently a day's total energy expenditure for the grazing form was almost constant. It indicates that the day-to-day difference in forage intake was not great.