Influence of full-time housing in vector-protected facilities on equine cortisol levels, heart rate, and behavior during the African horse sickness outbreak in Thailand

Horses were provided full-time housing in unfamiliar vector-protected facilities during the African horse sickness (AHS) outbreak in Thailand. This study aimed to investigate the impact of this housing arrangement on the equine stress response. Nine healthy horses were housed in both a traditional barn and a vector-protected barn. Equine behavior and stress response data were collected in association with the housing environment and time of day. The mean behavioral score of horses housed in the vector-protected barn was lower at night than during the day. In addition, the horses’ mean heart rate at night was lower than their heart rate during the day, irrespective of housing condition. Furthermore, although blood cortisol peaked at 6:00 AM and was lowest at 6:00 PM under both housing conditions, daily fluctuations in blood cortisol levels were correlated with changes in humidity and temperature in both environments. Finally, horses housed in the traditional barn exhibited earlier decreases in cortisol levels relative to the horses in the vector-protected barn. This result indicates that housing horses in vector-protected facilities may impose stress.

在泰国暴发非洲马瘟（African horse sickness, AHS）疫情期间，受试马匹全程饲养于陌生的媒介生物防护设施内。本研究旨在考察此种饲养模式对马属动物应激反应的影响。本研究选取9匹健康马匹，使其分别在传统马厩与媒介生物防护马厩中饲养。研究人员结合饲养环境与当日时段，采集了马属动物的行为学与应激反应相关数据。结果显示，饲养于媒介生物防护马厩的马匹，其夜间平均行为评分低于日间水平。此外，无论所处饲养环境如何，受试马匹的夜间平均心率均低于日间心率。进一步分析发现，在两种饲养环境下，血液皮质醇浓度均于上午6:00达到峰值、下午6:00降至最低；且两种环境中，血液皮质醇的每日波动均与环境温湿度变化呈显著相关。值得注意的是，相较于媒介生物防护马厩中的马匹，传统马厩内的受试马匹血液皮质醇浓度下降更早。该结果表明，将马匹饲养于媒介生物防护设施中或会引发应激反应。