Assessment of a vaquejada horse training protocol based on laboratory clinical parameters

The objective of this study was to assess a training protocol employed in the Brazilian Northeast region for fitness conditioning of vaquejada horses. For 12 months, 24 Quarter Horses were evaluated under a completely randomized split-plot experimental design in which the plots comprised three age groups: horses at two, three, and four years of age. The split plots were made up of six fitness tests carried out every other month. The fitness test protocol consisted of five levels of protocol exercises on a standard vaquejada track. Prior to the tests with fasted animals, we collected blood samples to determine muscle enzymes (aspartate aminotransferase, creatine kinase, and lactate dehydrogenase). During the tests, heart rate, speed, and distance run were recorded using a heart rate monitor. Next, the results were used to calculate speed at which each horse reached 150 bpm (V150), speed at which each horse reached 200 bpm (V200), maximum heart rate (HRmax), maximum speed (Vmax), recovery time needed for the heart rate of horses to return to half the maximum value reached during the fitness tests (HR50%), and recovery time needed for the heart rate of horses to return to baseline values (HRbasal). No difference was found among the age groups for V150, HRmax, Vmax, HR50%, HRbasal, or muscle enzymes. By the final stage of training, the V200 of the three-year-old horses was higher than that of the four-year-old foals. During training, all groups exhibited increases in serum concentrations of muscle enzymes and reductions in efficiency to recover heart rate after exercise. The training protocol assessed is unable to maintain proper fitness for competitions throughout the yea