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

Effects of winter weather on the growth rate and heat production of dairy cattle

“…The results reviewed above, and the present results, suggest that body insulation is lower for Friesian and Jersey cattle than for beef breeds; they also suggest, in association with the previous results of Holmes & McLean (1975), that the values for Jersey cattle are likely to be lower than for Friesian cattle. These differences may be explained, at least in part, by differences in hair coat characteristics and probable differences in body fat cover between breeds; it should be noted that neither of the Jersey cows used in the present experiment were in good condition.…”

“…When this is taken into account, together with the fact that even under calm conditions outdoors, windspeed was greater than 2 km/h, the present highest values for calm dry conditions with Friesian bulls are similar to those reported by Holmes & McLean (1975) for indoor measurements with Friesian calves, and the highest values for Jersey cows are slightly lower than those of the latter authors for Jersey calves. All of these values are considerably lower than those of Webster (1974) for various categories of beef cattle during winter in Canada, but there appear to be very few published measurements for dairy breeds of cattle.…”

“…Nevertheless the influence of wetting on apparent body insulation (see Methods) reflects a real influence on energy metabolism and is therefore important. Holmes & McLean (1975) reported that total heat production of young calves was increased by rain. at low temperatures, and that this effect was greater when the rain was associated with wind.…”

A generic method to analyse yield gaps in feed-crop livestock systems

“…, and a heat production of Figure 3.3 Simulated heat production and measured heat production for experiments with steers of Blaxter and Wainman (1964) and with Friesian and Jersey calves of Holmes and McLean (1975 , which is higher than the minimum heat release simulated with the thermoregulation sub-model. Overall, the thermoregulation sub-model estimates minimum heat release reasonably.…”

“…) (Holmes and McLean, 1975). Coat length of the calves was not measured, but assumed to be fixed at 25 mm in model simulations.…”