Evaluation of the growth of Criollo foals using nonlinear models

Abstract

ABSTRACT The present study aimed to evaluate the growth of Criollo foals from birth to 800 days of age using Brody, Gompertz, Logistic, and Von Bertalanffy nonlinear models. The data utilized consisted of weight, height, chest circumference, and shin circumference taken from 75 foals kept in southern Brazil. Morphometric traits analyzed showed mean values ranging from 63 to 325 kg for weight, 0.92 to 1.32 m for height, 0.88 to 1.58 m for chest circumference, and 0.12 to 0.18 m for shin circumference. For the evaluated traits, all applied nonlinear models achieved convergence. The results indicated that the Brody model provided the best adjustments for weight, height, and chest circumference. Gompertz model was found to be the most suitable for describing the growth curve of shin circumference. The animals exhibited an increase in weight during the evaluated period. Height showed the most rapid increase until approximately 365 days of age, followed by a decrease, and a more homogeneous growth pattern thereafter. Chest circumference exhibited more uniform growth in animals from 365 days of age onwards, with slower growth and greater variability observed from 400 days of age. Shin circumference showed greater growth in the first months of age, remaining stable thereafter. We observed that 94 and 5% of the animals in the studied population did not meet the minimum values for height and chest circumference, respectively, according to the breed standards from 24 months of age. Our results can assist in selection and future studies with the Criollo breed.

Keywords

• chest circumference
• growth curve
• height
• horses
• shin circumference
• weight