obese horses

Obese horses can lose weight on a diet alone. But it might take a low-intensity exercise program to improve their insulin sensitivities, as well, Australian and British researchers have learned.

“Our results demonstrated that a program of dietary restriction that included 15 minutes of trotting exercise on five days per week was able to improve insulin sensitivity more than a program of dietary restriction alone,” said Nicholas Bamford, BVSc, PhD, MANZCVS, Dipl. ACVIM, of the University of Melbourne Faculty of Veterinary and Agricultural Sciences, in Werribee, Victoria, Australia.

Bamford and colleagues studied 24 obese horses and ponies (Standardbreds, Andalusians, and mixed-breed ponies). All animals received a reduced hay ration (1.25% of their body weight on a dry matter basis per day) and were kept on drylots for the 12-week study period. Half the animals—divided evenly across ages and breeds—also began a low-intensity exercise program (15 minutes of trotting on a horse walker, beginning and ending with five minutes of walking). They performed these exercises once a day, five days a week.

While all the horses lost weight and lowered their body condition scores more or less equally during the study, the exercised horses had better insulin sensitivity at the end of the study period, Bamford said. This is a good thing, because insulin sensitivity promotes healthy metabolism while its opposite—insulin dysregulation, which is often associated with obesity—can lead to consequences such as laminitis.

“Obesity has a high prevalence in many equine populations around the world and is a major concern due to the associations between obesity, insulin dysregulation, and laminitis,” Bamford said. “This problem can largely be attributed to an imbalance between energy intake and energy expenditure, where increasingly sedentary horses and ponies are provided regular access to energy-rich pastures or forages, sometimes coupled with the overfeeding of complementary feeds. Certain breeds also appear particularly prone to these problems and other factors, such as unnecessary rugging-up (blanketing), may also contribute.”

Owners of obese horses and ponies should consult a veterinarian or equine nutritionist to help develop an individualized protocol to help their animals lose weight and develop better insulin sensitivity, Bamford said.

“I would caution against any assumption that exercise can overcome poor nutrition or management strategies,” he added. “A suitable management plan must include strict dietary modification as well as increasing exercise, if possible. The aim is to reduce both the total calorie as well as the sugar and starch intake of the diet, using strategies such as reducing or eliminating pasture access, using grazing muzzles, and soaking hay. A ration balancer to ensure adequate protein, vitamin, and mineral intake could also be important, especially when feeding soaked forage or forage in reduced amounts.”

The study, “Influence of dietary restriction and low‐intensity exercise on weight loss and insulin sensitivity in obese equids,” was published in the Journal of Veterinary Internal Medicine.