Allometric Scaling in Two Sizes of Equids(Equus caballus)

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Tammy R. Bragg , Kathryn M. Smith.
Dr. Charlie Apter, Faculty Mentor.

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Allometry is the study of relative growth of body parts in relation to entire organisms. Individuals who do not possess identical relative dimensions occupy different positions along an allometric scale. Past studies in allometric scaling have focused on interspecies relationships. The present study focuses on intraspecies scaling of equids (Equus caballus) of two body types. Eight body dimensions, including body mass, were determined for 16 Quarter Horse and Paint mares (light body type) and 29 Percheron mares (heavy body type). Data were plotted both dimension to dimension and dimension to body mass. Results indicate the most closely correlated dimensions are body length and body mass with an R² of 0.882. Future studies will be applied to miniature mares and/or Arabian mares with possible extension to the opposite sex (geldings and/or stallions); future investigation will also focus on developing a formula for predicting weight based on easily measured body dimensions.