Equilíbrio ácido base de equinos Quarto de Milha em treinamento em Três Tambores

Abstract

The study aimed to evaluate the effects of exercise during Barrel Racing training on the acidic balance of 10 Quarter Horse equines. Were evaluated cardiac and respiratory rates, rectal temperature, hematocrit, sodium, potassium, lactate, hemogasometry (pH, pCO2, pO2, sO22 and tCO2) and the difference of strong ions (DIF) in three times, T1 - before exercise; T2 - immediately after two courses of Barrel Racing, intervals in 10 minutes, preceded by a heating of ten minutes; T3 - after one hour (under rest) of T2. From T1 to T3 the animals remained in water fasting. At rest (T1) all physical and laboratory parameters remained within the physiological limits. Immediately after exercise (T2), there was an increase in heart and respiratory rates, rectal temperature and a decrease in pH, HCO3 - and pCO2 values. Also after exercise (T2), there was a decrease in EB and tCO2 values in relation to baseline time (T1), whereas blood lactate concentration increased above physiological limits, reaching levels of hyperlactatemia (>5 mMol/L), resulting in decrease in the DIF. Sodium and chloride didn’t vary significantly between the times, and potassium decreased in T2, but all remained within physiological limits at all evaluated times. Only the pH returned to physiological limits at T3, and lactate, although reduced, remains high at this time. Therefore, after performing two Barrel Racing courses, horses maintained their sodium, chloride and potassium venous concentrations in physiological limits, but there was an increase in plasma lactate, reducing DIF. It was concluded that after two courses of Barrel Racing under training conditions, the horses presented hyperlactatemia, which, consequently, caused a metabolic acidosis and a decrease in DIF. After an hour of rest of the second course, the pH returned to physiological levels, with levels of HCO3 - and EB almost totally recovered, and normalized DIF, but the lactate still remained in high concentration.