The cold tolerance of beef and dairy type calves in the first weeks of life

Abstract

ABSTRACT 1. British Friesian (F) and Hereford × British Friesian (H × F) male calves were raised from about 3 days to 8 weeks of age at air temperatures of 5, 10 or 15°C. They were given a milk replacer diet supplying 950 kJ metabolizable energy/kg M 0·75 .24 h. 2. There was no effect of environmental temperature on weight gain in calves of either type. 3. Total heat loss measured in a direct calorimeter, increased by about 5 kJ/kg M 0·75 .24 h per °C fall in air temperature. It was the same whether calves were penned singly or in pairs. Heat loss from F calves was slightly, but not significantly, greater at all temperatures than from H × F calves. 4. The proportion of heat lost by evaporation (a measure of environmental warmth) increased with increasing air temperature and was greater for H × F than for F calves at 15°C. 5. Tissue insulation and external insulation values were similar for H × F and F calves. The calculated lower critical temperatures of the F and H × F calves were 10 and 8°C respectively. 6. The results are discussed in relation to the housing requirements of young calves.