Physiological and biochemical responses and hydration status in equines after two barrel racing courses

Abstract

Studies on biochemical constituents and hydration of horses in training or competitions are essential for the knowledge of their adaptive physiological and metabolic responses to the type of exercise inherent to the sport. The present research evaluated the effects of exercise on hydric status and physiologic and biochemical profiles in Quarter Horses during a barrel race training session. The design consisted of three evaluation times (T): at rest, before the start of physical activity (T0); immediately after a 10-minute warm-up trot and then running the barrel race courses twice with a 10-minute interval (T1); and after one hour’s rest after the second course (T2). The parameters analyzed were: heart rate (HR), respiratory rate (RR), body temperature (BT) and mucose color; the capillary refill time (CRT), packed cell volume (PCV), total plasma proteins (TPP), serum creatinine (CRE) and blood urea nitrogen (BUN) were evaluated and used to infer water status; plasma osmolarity (Osm) was measured; the electrolytes sodium (Na), potassium (K), chloride (Cl), total calcium (tCa), total magnesium (tMg) and phosphorus (P), plasma glucose (Glu) and lactate (Lac) and the muscle enzymes creattine kinase (CK) and aspartate aminotransferase (AST) completed the evaluated parameters. The data for the variables studied were submitted to ANOVA and the Tukey test at 5% probability. After exercise (in T1), HR, RR, BT, PCV, TPP, Glu, Lac, Cre increased (P<0.05), there was also increase in phosphorus and decrease in K (P<0.05), but there was no hypophosphatemia and hipokalemia, respectively. After rest (in T2), only glucose returned to baseline levels (T0) and, with lower mean values, HR, RR, BT, PCV, K and Lac did not return to baseline levels (T0), while P decreased (P<0.05). Osm, BUN, Na, Cl, tCa, tMg, CK and AST did not change between times (P>0.05). It was concluded that the maximum intensity exercise performed on two barrel race courses caused mild hemoconcentration, did not changed plasma osmolality or concentrations of important electrolytes and muscle enzymes of horses, but caused hyperlactatemia without the plasma lactate concentrations being fully recomposed after resting.

Effects of different load weights on the work performance and physiological and hematobiochemical responses in working water buffalo

“…The type, intensity, and duration of work cause transitory physiological and metabolic changes in animals [ 43 ]. For example, temperature, respiration, and pulse increase in response to physical work [ 44 ].…”

“…The increases in RR, pulse, HR, and RT observed in the present study are consistent with similar responses in Surti buffaloes [ 47 ], bullocks of Hariana cattle [ 24 ], and equids [ 20 , 48 ]. The increase in HR during exercise occurs in response to increased metabolic rates due to adrenaline and glycolysis; and also due to an increase in cardiac contraction to maintain an adequate blood flow for perfusion and tissue oxygenation, which is related to the increase in RR and pulse [ 43 , 49 ]. The change in body temperature is due to heat production resulting from muscle contraction during work [ 24 ].…”

“…In general, glu concentrations above reference values can be attributed to the activation of the hepatic processes of glycogenolysis and gluconeogenesis, which is a response to the energetic need to maintain muscle activity. In addition, increases in blood levels of cortisol and catecholamines, concomitant with a reduction in insulin, cause an increase in blood glu [ 43 , 45 ].…”

“…In this study, we observed significantly higher CK values after working, regardless of load weight. However, CK levels are also dependent on the physical performance of the animal, and therefore, maximum plasma CK activity does not provide a realistic assessment of the amount of muscle damage [ 43 ]. Previous studies have reported that CK and LDH levels are more related to increased muscle cell permeability during physical work than to actual tissue damage due to heavy workload or mechanical damage [ 20 , 27 , 53 ].…”

The Influence of Various Physical Activity on Hematological and Biochemical Parameters in Draft and Sport Horses

“…The values of glucose concentration in horses' blood vary depending on the intensity and type of exercise, but they move within the reference intervals (Hodgson and McKeever 2014). Physical activity induces dehydration which leads to changes in the concentration of total proteins (Trailović 2008), creatinine, urea, bilirubin, electrolytes, and calcium, which negatively affects sports performance in horses (McCutcheon and Geor 1996;Allaam et al 2014;Gomes et al 2020).…”