Gender Differences–Induced Changes in Serum Hematologic and Biochemical Variables in Mangalarga Marchador Horses After a Marcha Gait Competition

• Mangalarga Marchador horse is one of the most important breeds in Brazil.
• Biochemical and hematological changes were observed in horses after exercises.
• Mares are more sensitive to exertion than horses during

The aim of this study was to investigate whether marcha exercise results in changes in serum hematologic and biochemical variables and whether this condition differs in male and female horses. Thirty-five Mangalarga Marchador horses, 18 males and 17 females were included in the study. Blood samples were obtained before and immediately after a marcha competition. Samples were used for measurement of hematocrit (HCT), hemoglobin concentration (HGB), red blood cell (RBC), total and differential white blood cell (WBC), total protein (TP), albumin (Alb), aspartate aminotransferase (AST), gamma glutamyltransferase (GGT), creatine kinase (CK), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatinine (Crea), and urea (BUN) levels. Data were submitted to analysis of variance using the SAS statistical program, and means were compared by the Tukey test (P < .05). In both males and females, RBC, HCT, AST, and GGT activity increased in response to exercise, but there were no significant differences between genders. In females, significant increases in TP, BUN, Crea, CK, and LDH levels were detected after the marcha gait, but no such changes were detected in males. Total WBC concentrations increased in response to the exercise in both, males and females; however, there were no differences between genders. Plasma HGB, Alb, and ALP levels after marcha gait did not differ in both genders. Marcha exercise–induced significant hematologic and biochemical changes in serum of Mangalarga Marchador horses, independently of gender. However, females presented more blood changes after marcha gait. Gender differences should be taken into consideration in experiments with athletic horses.