Heart rate and blood biomarkers in Brazilian gaited horses during a standardised field gaited test

Abstract

There is little information about biochemical and physiological parameters in Brazilian gaited horses that could be used to develop training and performance evaluation programs. The aims of the current study were to evaluate heart rate (HR) and blood biomarkers in gaited horses during a standardised field gaited test (SGT). Sixteen horses were used to develop an SGT (10 min of warming up, 30 min of marcha gait and 15 min of recovery). Blood samples and HR were collected at rest, after warming up, after 15 (F+15) and 30 (F+30) min of marcha, and after the recovery period. The following blood parameters were measured: glucose, lactate, total plasma protein, haematocrit, urea, creatinine, glutamine, glutamate, triglycerides, total cholesterol, Ca, P, Mg, Na, Cl and K. HR measurement was carried out using an HR monitor. The results were analysed using one- and two-way ANOVA tests, and post-hoc Holm-Sidak tests. Student's t-tests were used to compare means, and the Pearson's test was utilised for correlation analyses. Glucose and lactate increased during SGT (P<0.05), and a statistically significant interaction between phase of SGT and fitness level was observed for glucose. Additionally, haematocrit, total plasma protein, urea, creatinine, triglycerides, P and K were elevated (P<0.05), and a reduction of Ca was detected during the SGT (P<0.05). HR increased from ∼47 bpm at rest to ∼140 bpm at F+15 and F+30 (P<0.05). In conclusion, the HR and energetic biomarkers were increased during the SGT. HR was under the limit variation for values considered as submaximal for aerobic exercises in gaited horses during SGT. Additionally, some degree of dehydration was observed at the end of the marcha contest. This information may be used to better understand how gaited horses expend their energy during marcha events and to help determine a horse's fitness level.