Effects of weight, temperature and behaviour on the circadian rhythm of salivary cortisol in growing pigs.

摘要: In farm animals, salivary cortisol has become a widely used parameter for measuring stress responses. However, only few studies have dealt with basal levels of concentration in pigs and its circadian rhythm. The aim this study was to examine the effects ambient temperature thermoregulatory behaviour on rhythm fattening pigs. Subjects were 30 different weight (60 100 kg), kept six groups an uninsulated building pens partly slatted floors. Saliva samples taken every 2 h over periods 24 at temperatures two times winter four summer. Thermoregulatory recorded same 24-h time periods. effect day, body weight, level analysed using mixed-effects model. Two peaks per day found. This pattern became more pronounced increasing days where shown. Mean affected by but not behaviour. From our data, we conclude that long-term variations may be influenced age than respective experimental situation. assessing animal welfare, it seems reliable consider instead one value day.