Weight prediction from linear measures of growing Thoroughbreds

Reason for performing study: Monitoring weight of foals is a useful management practice to aid in maximising athletic potential while minimising risks associated with deviations from normal growth. Objective: To develop predictive equations for weight, based on linear measurements of growing Thoroughbreds (TBs). Methods: Morphometric equations predicting weight from measurements of the trunk and legs were developed from data of 153 foals. The accuracy, precision and bias of the best fitting equation were compared to published equations using a naïve data set of 22 foals. Results: Accuracy and precision were maximised with a broken line relating calculated volumes (Vt + l***) to measured weights. Use of the broken line is a 2 step process. Vt + 1 is calculated from linear measures (m) of girth (G), carpus circumference (C), and length of body (B) and left forelimb (F). Vt + l = ([G2 x B] + 4[C2 x F]) over 4π. If Vt + l