Effect of high temperatures on breeding rabbit behaviour

Abstract

The present work is focussed on the behavioural response of rabbits (Oryctolagus cuniculus) housed in typical commercial conditions subjected to two different environmental temperature circadian cycles: one below the combination of temperature and humidity that is considered as stressful for rabbits, and the other with some hours a day subjected to moderately stressful temperatures. During the experiment, a total of 55 commercial breeding hybrid rabbits were housed in each room (43 nulliparous does and 12 bucks). Of these, 10 females (six 105 days old and four 80 days old) and 6 males (180 days old) were studied for 12 days, 12 h a day using video cameras to later scan sample for behaviour at 5-min intervals. Rabbits were divided into two rooms. Five females and three males were housed at 18.4°C mean temperature (Room A). The other five females and three males were housed at 20.1°C for 17 h a day, and at a temperature humidity index from 23.6 to 28.2 for the remaining 7 h (Room B). Posture (lying, sitting, prostrated or moving) and behaviour (grooming, exploring, resting, feeding and drinking) were assessed. Faecal cortisol metabolites (FCM) were also analysed, once before and after the behavioural study, from seven samples in each room. Statistical analyses were performed using the GENMOD procedure in SAS. No differences were found between rooms in FCM during the behaviour assessment. However, the presence of resting behaviour and prostration was higher (P < 0.05) in Room B than Room A and the opposite (P < 0.05) was observed for lying, sitting and exploring. In the case of grooming, a compensatory effect was observed in Room B, as rabbits reduced this activity in the warmest period of the day but increased it just before and after this period, which was not seen in Room A. It is concluded that behavioural changes can be observed in does and bucks subjected to moderately stressful thermal conditions before those changes can be seen in faecal cortisol concentration.