Giles Sarah L, Nicol Christine J, Harris Patricia A, Rands Sean A
University of Bristol, School of Veterinary Science, Langford, Bristol BS40 5DU, UK.
WALTHAM Centre for Pet Nutrition, Equine Studies Group, Freeby Lane, Waltham-on-the-Wolds, Melton Mowbray, Leicestershire LE14 4RT, UK.
Appl Anim Behav Sci. 2015 May;166:71-79. doi: 10.1016/j.applanim.2015.02.019.
The aim of our study was to explore the association between dominance rank and body condition in outdoor group-living domestic horses, . Social interactions were recorded using a video camera during a feeding test, applied to 203 horses in 42 herds. Dominance rank was assigned to 194 individuals. The outcome variable body condition score (BCS) was recorded using a 9-point scale. The variables age and height were recorded and considered as potential confounders or effect modifiers. Results were analysed using multivariable linear and logistic regression techniques, controlling for herd group as a random effect. More dominant ( = 0.001) individuals generally had a higher body condition score ( = 0.001) and this association was entirely independent of age and height. In addition, a greater proportion of dominant individuals fell into the obese category (BCS ≥ 7/9, = 0.005). There were more displacement encounters and a greater level of interactivity in herds that had less variation in age and height, lending strength to the hypothesis that phenotypic variation may aid cohesion in group-living species. In addition there was a strong quadratic relationship between age and dominance rank ( < 0.001), where middle-aged individuals were most likely to be dominant. These results are the first to link behavioural predictors to body condition and obesity status in horses and should prompt the future consideration of behavioural and social factors when evaluating clinical disease risk in group-living animals.
我们研究的目的是探讨户外群居家养马的优势等级与身体状况之间的关联。在一项喂食测试中，使用摄像机记录了42个马群中203匹马的社交互动情况。为194匹马确定了优势等级。使用9分制记录结果变量身体状况评分（BCS）。记录了年龄和身高变量，并将其视为潜在的混杂因素或效应修饰因素。使用多变量线性和逻辑回归技术分析结果，将马群作为随机效应进行控制。优势更明显的个体（P = 0.001）通常身体状况评分更高（P = 0.001），并且这种关联完全独立于年龄和身高。此外，更大比例的优势个体属于肥胖类别（BCS≥7/9，P = 0.005）。在年龄和身高差异较小的马群中，有更多的驱赶遭遇和更高的互动水平，这支持了表型变异可能有助于群居物种凝聚力的假设。此外，年龄与优势等级之间存在很强的二次关系（P < 0.001），中年个体最有可能占据主导地位。这些结果首次将行为预测因素与马的身体状况和肥胖状况联系起来，并且应该促使在评估群居动物的临床疾病风险时，未来考虑行为和社会因素。
