Perfis hematológico, bioquímico, oxidativo e morfológico de cavalos crioulos em provas de laço comprido

Abstract

The Criollo is one of the main equine breeds used in the South of Brazil, including for one of the most practiced equestrian competitions, the long rope rodeo, wich looks like tie-down roping competition. The objective of this study is to characterize the type of physical exercise, its impact on the hematological, biochemical and oxidative profile of Criollo horses during long rope competition and determine the presence or absence of lesions at the cellular level resulting from the type of exercise they practice. Horses were randomly selected for two-day tests. In the equine register (n=49), the weight and body score were measured, and the hipometric measurements of each animal were collected, as well as information on breeding, feeding and training management, and the weight of the rider and type of saddlery. To characterize the competition, the length and depth of 11 arenas were measured and the time of each race of each horse (n=41) was timed. The cardiac and respiratory frequencies (n=27) were measured and the ambient temperature and blood samples were collected at 24 hours before the beginning of the competition (T0), after the last race of the last day of competition (T1) and 18 to 24 hours after the end of competition (T18). The hematological profile (n=19) was evaluated based on a complete blood count; the biochemical profile (n=28) was evaluated based on total proteins (PT), albumin, globulin, phosphorus (P), sodium (Na+), potassium (K+), aspartate aminotransferase (AST), creatine kinase (CK), lactate, urea, creatinine, glucose, triglycerides and cholesterol levels; and the oxidative profile (n=20) was examined by measuring thiobarbituric acid reactive species (TBARS), oxygen reactive species (ROS), uric acid and catalase (CAT). Statistical analysis was performed using a variance analysis (ANOVA) associated with the Tukey multiple comparison test, considered significant for P ≤ 0,05. The hipometric data of the evaluated animals were favorable in relation to the type of exercise practiced, as well as the equines studied present a greater body score than athletes of other races and modalities and has a management of breeding that resembles natural breeding and a feeding system composed by roughage and concentrated ration. Also, even without a standardized training management, the animals are apt for the evaluated exercise, which is required in high-intensity and short-duration exercises at an average speed of 6,4 m/s, which may vary according to the speed of the bovine, carrying on its back 25,6 % of its body weight. The exercise induced physiological alterations in cardiac and respiratory frequencies and na increase (P ≤ 0,05) of CK and lactate, both in T1. The intensity of exercise was not enough to stimulate glucose increases or decrease triglycerides as energy requirement and significantincreases (P ≤ 0,05) in creatinine and cholesterol were observed in T1 and T18. These alterations, associated with the hematocrit, hemoglobin, erythrocytes and PT increases (P ≤ 0,05), as well as the non-significant alterations of the indicators of oxidative stress and their returns in a timely manner demonstrate that the horses did not suffer damage caused by the type of exercise evaluated.