The impact of strategic ventilation adjustments on stress responses in horses housed full-time in a vector-protected barn during the African horse sickness outbreak in Thailand

Abstract

The severe outbreak of African horse sickness (AHS) in Thailand has forced horses to reside full-time inside barns that are covered by a small mesh net to prevent minuscule AHS insect vectors from gaining access. However, housing in the net-covered barn induces stress in horses, which compromises their welfare. Implementing strategic airflow adjustment while retaining the vector-protection characteristics has been proposed to help alleviate this problem. The present study aimed to investigate the effect of strategic ventilation adjustment on blood cortisol levels, heart rate and behaviour in horses in a vector-protected barn. Nine horses underwent two sequential stabling conditions: vector-protected barn housing and housing in a barn in which the air ventilation was explicitly adjusted. Heart rate was higher in the afternoon in horses housed in the barn without ventilation adjustment, whereas no change was observed in the barn with ventilation adjustment. The vector-protected housing increased the horses’ behavioural scores. Blood cortisol level declined over time, and an earlier decrease was detected at 1400h in the barn with ventilation adjustment. Although airflow adjustment did not appear to statistically alter the stress response in horses during housing in the vector-protected barn, an earlier decline in cortisol level alongside an unchanged heart rate in horses during the day may indicate the positive impact of ventilation adjustment within the vector-protected barn. With limited options to reduce stress or discomfort in horses, this strategic protocol could, at least in part, be applied to managing horses’ welfare during the AHS outbreak.

Cortisol levels, heart rate, and autonomic responses in horses during repeated road transport with different truck conditions trucks in a tropical environment

“…A difference in air-conditioning settings could explain this disparity. It has been reported that the relative humidity was significantly higher within a closed barn than in an outside barn [29, 30]. Likewise, the moisture production becomes pronounced, causing increased relative humidity in a closed-door, air-conditioned room of a human dwelling [31].…”

“…This finding may indicate, in part, that the N-ATS condition created more stress than the others. Cortisol levels are modulated by the circadian rhythm, peaking in the morning and then gradually reducing [29, 30, 32, 33]. Since our experiments were initiated in the morning and ended in the afternoon, it could be that increases in cortisol levels after transport were not under circadian rhythm but external stimuli from the transports.…”

“…This finding may indicate, in part, that the N-ATS condition created more stress than the others. Cortisol levels are modulated by the circadian rhythm, peaking in the morning and then gradually reducing [29,30,32,33].…”

Hematological and physiological responses in polo ponies with different field-play positions during low-goal polo matches

“…These results reflect the enormous stress on the ponies during highintensity exercise in the chukkas. However, a further decrease in cortisol levels (below the baseline) at 120-180 minutes may result from the hormone's circadian rhythm during the late evening [22,[56][57][58][59].…”