Oral creatine supplementation on performance of Quarter Horses used in barrel racing

Nutritional Influences on Skeletal Muscle and Muscular Disease

Skeletal muscle comprises 40% to 55% of mature body weight in horses, and its mass is determined largely by rates of muscle protein synthesis. In order to support exercise, appropriate energy sources are essential: glucose can support both anaerobic and aerobic exercise, whereas fat can only be metabolized aerobically. Following exercise, ingestion of nonfiber carbohydrates and protein can aid muscle growth and recovery. Muscle glycogen replenishment is slow in horses, regardless of dietary interventions. Several heritable muscle disorders, including type 1 and 2 polysaccharide storage myopathy and recurrent exertional rhabdomyolysis, can be managed in part by restricting dietary nonstructural carbohydrate intake.

The effect of repeated barrel racing on blood biomarkers and physiological parameters in Quarter Horses

The objective of this study was to evaluate barrel horses undergoing a field test with one repetition. Quarter-Horses were used (14 males and females; average age: 6.5 years old), and they ran two times for 5 min in the same field. Six different periods were evaluated: rest (T-0), immediately after the first (T-1) and second races (T-2), and after 15 (T-15), 30 (T-30) and 240 min (T-240) of recovery. Heart rate (HR), speed, distance and duration were measured using a HR monitor with GPS during the races. Blood was collected to determinate glucose, lactate, total proteins (TP), albumin, globulin, urea, creatinine, uric acid (UA), triglycerides, cholesterol, non-esterified fatty acids (NEFA), gammaglutamyltransferase (GGT), creatine kinase (CK), and cortisol concentrations, as well as to perform a haemogram. The results were analysed using ANOVA and Tukey’s tests using a P-value of 5%, and they showed a maximum HR>200 bpm after both races. The largest %HR>>170 bpm occurred in the second race (P<0.05). Glucose and lactate concentrations were elevated at T-2 (P<0.05). TP, creatinine, UA and triglycerides concentrations remained elevated at T-1, T-2 and T-30 (P<0.05). TP and creatinine concentrations returned to basal concentrations at T-30 (P>0.05), and UA and triglycerides returned to base concentrations at T-240 (P>0.05). NEFA, cholesterol, GGT and CK concentrations did not change (P>0.05). Cortisol concentrations were higher at T-2 (P<0.05) but at T-240 were similar to T-0 (P>0.05). Red blood cell concentrations and haematocrits had higher values after the second race (P<0.05). These results showed that barrel horses had intense exercise and that two races with a short rest interval between them produced similar metabolic and physiologic adaptations between races, showing that the proposed protocol may be a useful tool for field characterisation of horses’ training and may contribute to the implementation of adequate training and nutritional programs.