Estimation methods and correction factors for body weight in Mangalarga Marchador horses

ABSTRACT The objective was to evaluate the accuracy of six body weight (BW) estimating methods in Mangalarga Marchador horses (MM) (n = 318): method A - tape placements at three different positions around the thoracic girth; B - Crevat and Quetelec's formula; C - Hall's formula; D - Hintz and Griffiths’ table; E - Santos’ table; and F - Cintra's formula. For additional analyses, gender, age, and gestational stage were considered. Estimated average BW was compared to the actual scale weight by the paired T test, mean predicted error, and determination coefficient. In the general population, methods A (position 3), B, and C estimated BW that were different from that of the scale. Method A, at positions 1 and 2, was more accurate in predicting the scale weight results compared with all other methods. For pregnant mares, the tape in positions 1 and 2 in method A did not differ from those of the scale. Method A in positions 1 and 2 and the table (method E) may be used to estimate the BW of males and females of different ages and/or gestational stages. To use Methods B and C, correction factors are necessary to precisely estimate the body weights in this breed.

摘要 本研究旨在评估六种体重（Body Weight, BW）估算方法在曼加尔加加丘马（Mangalarga Marchador, 简称MM）中的准确性，共纳入318匹研究样本：方法A为在胸围三个不同位置使用软尺测量；方法B为Crevat与Quetelec公式；方法C为Hall公式；方法D为Hintz与Griffiths体重对照表；方法E为Santos体重对照表；方法F为Cintra公式。补充分析中纳入性别、年龄与妊娠阶段作为考察因素。将估算得到的平均体重与实际称重体重通过配对t检验、平均预测误差及决定系数进行比较。在总体种群中，方法A（位置3）、B及C的估算体重与实际称重结果存在显著差异。相较于其余所有方法，位置1和2的方法A在预测实际称重结果时精度更高。针对妊娠母马，位置1和2的方法A所得结果与实际称重结果无显著差异。位置1和2的方法A以及方法E（体重对照表）可用于估算不同年龄、不同性别以及不同妊娠阶段个体的体重。若使用方法B和C，则需引入校正因子才能精准估算该品种马的体重。