The heat of warming feed
A.M. Nicol and B.A. Young
Lincoln University, Canterbury and Dept. of Animal Science,
University of Alberta, Canada
Proceedings of the New Zealand Society of Animal Production.
1981, 41: 152-162
The results of a number of experiments in which sheep and cattle
consumed high moisture feeds (10% dry matter) at a range of feed
temperatures (1 to 38°C) and over a range of air temperatures (+ 10 to -
20°C) were summarised. Responses to cooling were a reduction in heat
loss and a decline in body temperature which could be accompanied by an
increase in heat production. The efficiency with which surplus
metabolic heat was used to warm feed was 50-60%. The pattern of heat
flow from the body to the rumen, which was function of the quantity and
temperature of the feed consumed, determined the animal response. The
heat flow from the body to the rumen was included as an additional heat
loss in the conventional heat loss model.
The consumption of large meals of cold (2°C) high moisture feeds by
sheep and cattle can raise their critical temperature by 15-20°C. This
change may not affect the heat production of well-insulated, well-fed
sheep or cattle. However, less well-insulated sheep and cattle at
maintenance levels of feeding are likely to increase their heat
production, at the expense of body tissue deposition to meet the thermal
demands of the heat of warming.
Keywords: NZSAPAB;
Last Updated 12-09-1998
