The aim of this research was to investigate the diurnal variation in the ear skin temperature and the lying behaviour at different environmental temperatures. Three repeated experiments were performed. In each experiment, 18 growing pigs were divided into three groups with six pigs each. The pigs have an average start weight of 75 +/- 5 kg. Each experimental period was 20 days. The temperature was changed from 18 ºC down to 10ºC and up again to 22ºC in two degrees steps. The pigs carried a special ear tag with a temperature sensor. The skin temperature at the ear was measured every three minutes and a mean temperature on the basis of five 3-minute values was computed and logged automatically into a computer. Behavior of the pigs was recorded for 24 hours at each set point temperature of 18ºC, 10ºC and 22ºC. General activity, lying posture and contact with pen matters were scored by 12 min scan sampling. A clearly diurnal variation pattern of the ear skin temperature was found, with the highest ear skin temperature level at night and the lowest level in the afternoon. For the behavioural observations it was found that the pigs tended to huddle more during the night comparing to the day and they tend to lay in the fully recumbent lying posture during night.
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American Society of Agricultural and Biological Engineers, ASABE, 2006