The differences of energy expenditure between cattle grazing on pasture and on native range were studied by Japanese Black Breed of Cattle. Three dry cows in prime age and the same number of lactating cows were used in these experiments.
The heat production was estimated by the indirect method previously reported by the authors.
The principal results obtained were as follows :
1. Heat production of the cows grazing on the pasture was less than that on the range in all grazing behaviors. The lactating prime cow produced more heat than the dry cow.
2. The energy expenditure during 24 hours by grazing cow on pasture was found to be 30 Cal.per kg. B. W. or 11,000 Cal. per head in round numbers. These values on pasture were about 20% less than those on range.
3. The distance walked by the cow in 24 hrs. on pasture varied from 2.1 km to 4.5 km, but it was nearly one half of the range cow previously studied.
4. It is suggested from these data that the energy expenditure of grazing cattle might have a possibly to decreese considerably by the improvenment of quality and quantity of grass on the range or pasture.