Martinson K L, Coleman R C, Rendahl A K, Fang Z, McCue M E
Department of Animal Science, University of Minnesota, St. Paul 55108.
J Anim Sci. 2014 May;92(5):2230-8. doi: 10.2527/jas.2013-6689. Epub 2014 Mar 18.
Excessive BW has become a major health issue in the equine (Equus caballus) industry. The objectives were to determine if the addition of neck circumference and height improved existing BW estimation equations, to develop an equation for estimation of ideal BW, and to develop a method for assessing the likelihood of being overweight in adult equids. Six hundred and twenty-nine adult horses and ponies who met the following criteria were measured and weighed at 2 horse shows in September 2011 in Minnesota: age ≥ 3 yr, height ≥ 112 cm, and nonpregnant. Personnel assessed BCS on a scale of 1 to 9 and measured wither height at the third thoracic vertebra, body length from the point of shoulder to the point of the buttock, neck and girth circumference, and weight using a portable livestock scale. Individuals were grouped into breed types on the basis of existing knowledge and were confirmed with multivariate ANOVA analysis of morphometric measurements. Equations for estimated and ideal BW were developed using linear regression modeling. For estimated BW, the model was fit using all individuals and all morphometric measurements. For ideal BW, the model was fit using individuals with a BCS of 5; breed type, height, and body length were considered as these measurements are not affected by adiposity. A BW score to assess the likelihood of being overweight was developed by fitting a proportional odds logistic regression model on BCS using the difference between ideal and estimated BW, the neck to height ratio, and the girth to height ratio as predictors; this score was then standardized using the data from individuals with a BCS of 5. Breed types included Arabian, stock, and pony. Mean (± SD) BCS was 5.6 ± 0.9. BW (kg) was estimated by taking [girth (cm)(1.48)6 × length (cm)(0.554) × height (cm)(0.599) × neck (cm)(0.173)]/3,596, 3,606, and 3,441 for Arabians, ponies, and stock horses, respectively (R(2) = 0.92; mean-squared error (MSE) = 22 kg). Ideal BW (kg) was estimated by taking [length (cm) × 2.8] + [height (cm) × 4.2] - 611, 606, and 577 for Arabians, ponies, and stock horses, respectively (R(2) = 0.86; MSE = 24). Equids with a BCS of ≥ 7 had a greater likelihood of being overweight, and the model suggested cutoffs at the 48th and 83rd percentiles for underweight and overweight individuals, respectively. Morphometric measurements were successfully used to develop equid BW-related equations.
超重已成为马（Equus caballus）产业中的一个主要健康问题。目标是确定增加颈围和身高是否能改进现有的体重估计方程，开发一个估计理想体重的方程，并开发一种评估成年马属动物超重可能性的方法。2011年9月在明尼苏达州的2场马匹展览会上，对629匹符合以下标准的成年马和矮种马进行了测量和称重：年龄≥3岁，身高≥112厘米，且未怀孕。工作人员按照1至9的评分标准评估体况评分（BCS），并测量第三胸椎处的鬐甲高度、从肩部到臀部的体长、颈部和胸围，以及使用便携式家畜秤测量体重。根据现有知识将个体分为不同的品种类型，并通过形态测量的多变量方差分析进行确认。使用线性回归模型开发估计体重和理想体重的方程。对于估计体重，模型采用所有个体和所有形态测量数据进行拟合。对于理想体重，模型采用BCS为5的个体进行拟合；考虑品种类型、身高和体长，因为这些测量不受肥胖影响。通过使用理想体重与估计体重之差、颈高比和胸围高比作为预测因子，对BCS拟合比例优势逻辑回归模型，开发了一个评估超重可能性的体重评分；然后使用BCS为5的个体数据对该评分进行标准化。品种类型包括阿拉伯马、役用马和矮种马。平均（±标准差）BCS为5.6±0.9。阿拉伯马、矮种马和役用马的体重（千克）分别通过[胸围（厘米）(1.48)6×体长（厘米）(0.554)×身高（厘米）(0.599)×颈部（厘米）(0.173)]/3596、3606和3441来估计（R(2)=0.92；均方误差（MSE）=22千克）。阿拉伯马、矮种马和役用马的理想体重（千克）分别通过[体长（厘米）×2.8]+[身高（厘米）×4.2]-611、606和577来估计（R(2)=0.86；MSE=24）。BCS≥7的马属动物超重的可能性更大，该模型分别建议体重过轻和超重个体的临界值为第48百分位数和第83百分位数。形态测量成功用于开发与马属动物体重相关的方程。
