Predição do peso vivo de garrotas e novilhas do grupo genético Girolando a partir de medidas corporais

Abstract

The use of zootechnical indices in the production environment is essential forworking with precision, with live weight being a crucial factor for monitoring thedevelopment and decision-making with animals. This study aimed to estimate theweight of Girolando animals in the categories of young crossbred heifers with Holsteingenetics (1/2 and 7/8) and (1/2 and 3/4) crossbred heifers, based on morphometricmeasurements. To this end, 110 young heifers, 299 3/4 heifers, and 32 1/2 heiferswere weighed (kg) using a scale and measured (cm) with a tape measure to obtainchest girth (CG), and a hypometer was used to measure withers height (WH) and bodylength (BL). For the heifers, additional measurements were taken: rump height (RH)using the hypometer and forearm perimeter (FP) using the tape measure. Theprocedures proc means, proc cor, and proc reg of SAS were used to obtain the means,correlations between weight and measurements, and the regression equations,respectively. For young heifers, the equation “Weight = - 56.4227 + 0.01378 * TG²”was selected. For 1/2 heifers, the equation “Weight = 61.49 + 0.000056 * TG³” providedthe most accurate weight estimate, while for estimating the weight of 3/4 heifers, theequation “Weight = 52.82 + 0.000061 * TG³” was used. Some equations showedslightly higher coefficients of determination; however, a greater number of bodymeasurements were required for weight estimation. The selected equations presentedR² values of 0.96, 0.83, and 0.93, respectively, using only chest girth to estimate theanimals’ weight. As a result, it was possible to estimate the weight of the animals fromboth categories effectively and in a cost-efficient manner