Vitamin D biology in equids is unique and poorly understood. Naturally managed (grazing) horses rely on dietary vitamin D2 (ergocalciferol) to provide adequate vitamin D, because endogenous ultraviolet radiation-mediated synthesis of vitamin D3 (cholecalciferol) is ineffective in this species. To test the hypothesis that the management of stabled, nongrazing racehorses is a risk factor for […]

Recovery from intense exercise is crucial in the equine athlete and numerous nutritional interventions have been proposed to benefit exercise recovery. Branched-chain amino acids (leucine, isoleucine, valine; BCAA) have been associated with improved muscle protein synthesis post-exercise. N-acetylcysteine (NAC) is a precursor to glutathione, a powerful antioxidant involved in many biological pathways, and supplementation has […]

In the mitochondria, complexes I and III of the electron transport system (ETS) generate reactive oxygen species (ROS) during exercise that are reduced by antioxidants to mitigate oxidative stress. Among these antioxidants are thiol-based antioxidants such as glutathione as well as coenzyme Q10 (CoQ10), which also transports electrons from complex I and II to complex […]

Skeletal muscle citrate synthase (CS) activity serves as a marker for muscle oxidative capacity. CS activity was compared among Quarter Horses (QH), Arabians (AR),  Thoroughbreds (TB), Standardbreds and Warmbloods at various ages and stages of training. Gluteus medius muscle biopsies were obtained at ages 6–23 m (n = 10), 2 y (n = 37), 3 […]