Effects of air temperature and air movement on the heat produced by young Friesian and Jersey calves, with some measurements of the effects of artificial rain

Abstract

Measurements were made of the oxygen consumption and carbon dioxide production of Friesian and Jersey calves aged between 7 and 60 days. During the measurements each calf was exposed to several environmental conditions: temperature was controlled at 3°, 8°, 12°, and 20°c, air movement was controlled at 0.8 or 5.6 km/h, and simulated rain was produced from a spray nozzle for 4- or 8-h periods. Calculated heat production was increased considerably at the lower temperatures, and by the faster air movement at lower temperatures, effects being greater for Jersey than for friesian calves. Exposure to 4 h of simulated rain at Soc also increased heat production, this effect being greater with the faster air movement. Whole body conductance was about 14% lower for the Friesian calves than for the Jersey calves, this difference being associated with heavier hair coats on the Friesian calves The results are discussed in relation to the importance of climatic factors to calves in New Zealand.