High glycemic and insulinemic responses to meals affect plasma growth hormone secretory characteristics in Quarter Horse weanlings

Potential use of beet-pulp concentrate supplementation in athletic horse

The aim of this two-phase study was to evaluate the use of beet pulp concentrate (BPC) in athletic horses. On the first trial the effects of supplementation with 820g of BPC for 12 weeks were assessed and a crossover postprandial curves of blood biomarkers were determined in five adult Arabian mares. Differences were found in T-chol, HDL-chol, TPP and MCHC (p < 0.05). Postprandial curves varied among challenges (p < 0.05) for glucose, insulin, and hematocrit. These results confirmed that BPC supplementation led to changes in blood biomarkers, without inducing major metabolic disruption. The aim of the second trial was to evaluate effects of resistance training using a horse walker in eight yearling gaited foals fed with BPC (16 %) for 12 weeks. Blood samples were collected before and at 30, 60 and 90 days of training and results demonstrated the highest level of [NEFA] and [triglycerides] at end of experimental period (p < 0.05) and increased of growth hormone after exercise sections after 60 days (p < 0.05). Also, [MCHC] and [Hb] increased 30 days after beginning of training program (p < 0.05), maintaining until the end of trial period. Association of the training program with highly digestible fiber as BPC possibly led to a greater availability of NEFA and hCG certainly helping the physical conditioning of these young animals.

Circadian and Circannual Regulation in the Horse: Internal Timing in an Elite Athlete

Biological rhythms evolved to provide temporal coordination across all tissues and organs and allow synchronization of physiology with predictable environmental cycles. Most important of these are circadian and circannual rhythms, primarily regulated via photoperiod signals from the retina. Understanding the nature of physiological rhythms in horses is crucially important for equine management. Predominantly, they have been removed from exposure to their natural environmental stimuli; the seasonally changing photoperiod, continuous foraging and feeding activity, social herd interactions, and the continuous low-intensity exercise of a grassland dweller. These have been replaced in many cases with confined indoor housing, regimental feeding and exercise times, social isolation, and exposure to lighting that is often erratic and does not come close to mimicking the spectral composition of sunlight. Man has further altered seasonal timing cues through the use of artificial lighting programs that impact reproductive behavior, breeding efficiency, and the development of youngstock. Understanding how these new environmental cues (some stronger and some weaker) impact the internal physiology of the horse in the context of the natural endogenous rhythms that evolved over millennia is key to helping to improve equine health, welfare, and performance, now and into the future. This review provides an overview of the field, highlights the recent discoveries related to biological timing in horses, and discusses the implications that these findings may have for the production and management of the elite equine athlete.