The effect of rubber slat mats on cortisol concentrations in stall-housed gilts

Abstract

It has been established that rubber mats improve lying comfort in stall-housed gilts at low ambient temperatures. The present study investigated whether rubber mats influence stress levels in gilts by improved lying comfort. The study was performed in a commercial pig farm service unit, during the 28-day breeding cycles in autumn and winter. During both cycles, the control and experimental groups of gilts (9 gilts each) were housed in gestation stalls with a concrete slatted floor; in the experimental groups, the floor was additionally coated with adjusted 2-cm thick rubber mat. Stress level was assessed by determination of cortisol concentrations in gilt serum on days 1, 8, 15 and 28 of each cycle, when the postural behaviour of gilts was observed. In both groups of gilts, serum cortisol was significantly lower (P lt 0.05) on day 28 as compared with day 1 in both breeding cycles. However, on day 28, significantly lower (P lt 0.05) serum cortisol was measured in the experimental group as compared with the control group. There was a negative correlation between cortisol concentrations and the time that experimental gilts spent lying in total, and lying laterally (r = -0.46 and r = -0.52, respectively, P lt 0.05) and a positive correlation between cortisol concentrations and time spent standing (r = 0.43, P lt 0.05). In the control group, there was no significant correlation between serum cortisol concentrations and the postures observed, except for sitting (r = 0.55, P lt 0.05), but a correlation was recorded between cortisol concentrations and posture changing (r = 0.33, P lt 0.05). In conclusion, the use of rubber mats proved to be an efficient management tool to reduce stress levels in gilts by improving their lying comfort.