The effect of milk given at various temperatures on the oxygen consumption of young calves

Abstract

SUMMARY: 1. Measurements of oxygen consumption and rectal temperature were made on young female calves at air temperatures of 9° and 20°C, before and after 4·5 kg milk was drunk at 23° and 39°C.2. When cool milk (23°C) was drunk at an air temperature of 9°C, vigorous shivering occurred, and during the 2-hr period after feeding, oxygen consumption was significantly higher than in the three other treatments.3. In all other treatments oxygen consumption increased considerably during the 30-min period which included drinking activity; the average increment, when no thermo-regulatory shivering occurred, was 1·9 ml O₂ min^−1kg−1.4. It was estimated that the 58 kcal ‘heat of warming’ required by milk at 23°C drunk at an air temperature of 9°C could be accounted for by the increment in heat production during the 2 hr after feeding and the fall in rectal temperature of 0-2-0-3°C which persisted after feeding in this treatment. These calculations suggested that the effect of a cool liquid on the energy balance of an animal would be less than that predicted from the ‘heat of warming’ required by the cool liquid.