360 Awardee Talk - weight loss strategies in horses

Abstract

Abstract Almost half of the American horse population is reported to be overweight, with approximately 20% reported as obese. Excessive adiposity is associated with potential health consequences including joint disease, heat intolerance, insulin resistance, equine metabolic syndrome, and laminitis. Health management for affected horses includes strategies that not only decrease fat mass but also improve insulin dynamics, as insulin resistance is closely associated with the development of laminitis. Negative energy balance to achieve fat loss can result from decreased caloric intake, increased energy expenditure, or a combination of both. Decreased calorie intake can be achieved by limiting feed intake by reducing the amount of feed offered, limiting pasture intake (through the use of grazing muzzles or limiting time at pasture), and by selecting lower energy density feeds. Weight-loss research has suggested feeding forages at a rate of 1.5% of body weight (90% DM), balanced with appropriate amounts of amino acids, vitamins and minerals as needed. Some horses appear to be “weight loss resistant” and may require further restrictions under veterinary supervision (closer to 1.0 - 1.2% of body weight). Strict feed restriction may increase the risk of hyperlipidemia, colic, gastric ulcers, the onset of wood chewing behavior and/or the consumption of bedding. Several studies have reported significant weight loss with restricted dietary energy intake, though effects on insulin dynamics are varied. Forced exercise not only increases energy expenditure, but also results in more pronounced improvements on insulin dynamics. Light, moderate and heavier exercise protocols have resulted in improvements in insulin sensitivity, with greater benefits along with fat loss being associated with higher workloads. However, lameness may compromise weight-bearing exercise efforts. It is recommended that weight loss strategies for horses incorporate both dietary energy restriction and increased exercise when possible.