MED - Mediterranean Institute for Agriculture, Environment and Development, Institute for Advanced Studies and Research, Universidade de Évora, Pólo da Mitra, Ap. 94, 7006-554, Évora, Portugal.
VALORIZA - Research Centre for Endogenous Resource Valorization, Edifício BioBIP, Campus Politécnico, 10, 7300-555, Portalegre, Portugal.
BMC Vet Res. 2021 Oct 14;17(1):329. doi: 10.1186/s12917-021-02985-9.
The purpose of this study was to investigate the usefulness of salivary cortisol (SC) and eye temperature measured by infrared thermography (IRT) as biomarkers to manage competitions more effectively and monitor horse welfare in endurance competitions. Based on previous studies, it was hypothesised that pre-exercise baseline SC and IRT would be higher in younger or less experienced horses, and that post-exercise variation from baseline would be higher in the top finishers.
Salivary cortisol measured in 61 competing at qualifier 40 km and 80 km rides showed an abrupt variation (93-256% rise) of the baseline SC levels [median ± interquartile range (IQR) = 0.27 ng/dl ± 0.36] obtained at the Pre-Inspection (PI) into Vet Gate (VG)1 independently of the covered distance, but modest or even lower in the subsequent Vet Gates, e.g. VG2 or VG3. The IRT measured concomitantly in 16 horses showed significant (p < 0.05) higher levels at the PI in less experienced horses participating in the 40 km ride (median ± IQR = 35.7 °C ± 1.4) than their counterparts in the 80 km ride (median ± IQR = 35.0 °C ± 1.5), but not SC. Baseline SC levels at the PI of horses classifying in the Top5 in the 40 km ride category were significantly (p < 0.05) higher median ± IQR = 0.90 ng/ml ±0.61) when compared to horses positioned from 10th position on (median ± IQR = 0.16 ng/ml ±0.40). A lower IRT in the PI was correlated with better placement (p < 0.05) and those in the Top5 (median ± IQR = 33.9 °C ± 0.0) had a significantly (p < 0.5) higher variation (+ 10.65%) into the last VG.
Pre-exercise baseline IRT levels, but not SC, were higher in less experienced horses in the 40 compared to their counterparts in the 80 km ride competitions. SC and IRT showed different indications according to the competition. In the40 km ride competition, higher baseline pre-exercise SC levels seemed to be linked to a better classification outcome. In contrast, in the 80 km ride horses, the higher IRT variation from pre-exercise into final Vet Gate was the parameter associated with a better performance. A more controlled environment and a larger sample are needed to confirm these results and monitor horse welfare in competitions.
本研究旨在探讨唾液皮质醇（SC）和红外热成像（IRT）测量的眼温作为生物标志物的有效性，以便更有效地管理比赛并监测耐力比赛中的马匹福利。基于先前的研究，我们假设运动前基线 SC 和 IRT 在年轻或经验较少的马匹中会更高，而在顶级完赛者中，运动后与基线的变化会更高。
对 61 匹参加资格赛 40 公里和 80 公里比赛的马匹进行了 SC 测量，结果表明，基线 SC 水平（0.27ng/dl±0.36）在 Pre-Inspection（PI）到 Vet Gate（VG）1 处的急剧变化（93-256% 升高）与覆盖的距离无关，但在随后的 Vet Gates 中，如 VG2 或 VG3，变化较小或甚至更低。同时在 16 匹马中测量的 IRT 显示，在参加 40 公里比赛的经验较少的马匹中，PI 处的水平显著升高（p<0.05）（中位数±IQR=35.7°C±1.4），而在 80 公里比赛中的马匹（中位数±IQR=35.0°C±1.5）则没有。在 40 公里比赛中排名前 5 的马匹的 PI 处的基线 SC 水平显著升高（p<0.05）（中位数±IQR=0.90ng/ml±0.61），而排名第 10 位的马匹的基线 SC 水平（中位数±IQR=0.16ng/ml±0.40）则没有。PI 处较低的 IRT 与更好的排名（p<0.05）相关，而前 5 名的马匹（中位数±IQR=33.9°C±0.0）的变化（+10.65%）显著增加（p<0.05）进入最后一个 Vet Gate。
与 80 公里比赛相比，在 40 公里比赛中，经验较少的马匹的运动前基线 IRT 水平较高，但 SC 水平则没有。SC 和 IRT 根据比赛呈现出不同的指示。在 40 公里比赛中，较高的运动前基线 SC 水平似乎与更好的分类结果有关。相比之下，在 80 公里比赛中，从运动前到最后一个 Vet Gate 的 IRT 变化与马匹的表现相关。需要更受控的环境和更大的样本量来证实这些结果，并监测比赛中的马匹福利。
