Comparação entre o peso corporal estimado por equações de regressão e o peso corporal obtido por fita comercial para pesar equinos da raça “Brasileiro de Hipismo”

Abstract

Knowledge of live body weight in horses is essential from birth (monitoring of weight development), throughout their athletic career (competition weight), and during their reproductive life (body weight at the onset of the breeding season). In addition, accurate body weight determination is necessary to establish nutrient requirements for maintenance, to calculate appropriate dosages of anthelmintics and medications (antibiotics), and to determine the optimal timing for the initiation of training. The use of a scale is the most accurate method for obtaining animal body weight (kg); however, in the absence of a scale or when scales are not properly calibrated, as reported by Wood, Reyher, and Barret (2015), body weight can be estimated using regression equations based on morphometric measurements. In this study, several equine body weight prediction equations available in the literature, as well as those developed by Martins et al. (in press), were reviewed with the objective of comparing body weight obtained using a commercial equine weigh tape (model “Iaber Inovation”) with body weight estimated from thoracic girth (PT), cannon bone circumference (PC), and withers height (AC) measurements in horses of the Brazilian Sport Horse breed from the JLP Equestrian Center, located in the Castelão district, Fortaleza, Ceará, Brazil. Body weight was expressed in kilograms and measurements in centimeters. The results showed that the regression equations evaluated generally exhibited strong correlations with body weight measured using the commercial weigh tape, for both mares and stallions of the Brazilian Sport Horse breed at the JLP Equestrian Center. Among the equations analyzed, the one corresponding to variable Weight16 stood out for presenting the smallest mean differences in comparison with the weight measured by the tape, with values of 9.66 kg for mares and −5.11 kg for stallions, in addition to high correlation coefficients. Conversely, the equation corresponding to Weight11 showed larger mean differences, suggesting a tendency to overestimate body weight, despite its high correlation. These findings indicate that the selection of the most appropriate equation for estimating live body weight should consider not only statistical correlation but also the magnitude of differences relative to the reference method, highlighting the Weight16 equation as the most suitable for practical application.