Behavioural and physiological measures of welfare of pregnant mares fitted with a novel urine collection device

Mares wearing the PMU collection device showed little or no behavioural change relative to the control mares. While brief bouts of forward lifting of the hind leg in the region of the PMU collection device were observed in some mares on day 1, this disappeared by day 2. Observations on the time budgets of behaviour in weeks 3 and 6-7 indicated similar patterns of behaviour in the two treatments. The only difference in behaviour was in lying behaviour. PMU collection mares spent less (P < 0.01) time lying during the night, with fewer horses observed lying down in the PMU collection treatment (4/11 versus 10/12). It is unclear what implication this may have on horse welfare since there was no evidence of a rebound in this behaviour when the device was removed. Based on heart rate and cortisol concentrations measured on days 1 and 2 of study, there was no evidence of acute stress associated with fitting the device. Limited measurements on salivary cortisol concentrations at weeks 6-7 of the study provided no evidence of an increase in basal cortisol concentrations or an increase in the sensitivity of the adrenal cortex to ACTH in the PMU collection mares. Therefore, it is concluded that wearing the PMU collection device at night for five nights per week for a total of 6-7 weeks does not pose a serious challenge to the welfare of pregnant mares.