Addressing the 'Air Fern' in Your Barn
Roly-poly, cresty-necked horses and ponies might be well-loved, even adored by their owners, but in reality, they are in harm’s way. Obese equids are at a high risk for developing serious metabolic problems and the hoof disease laminitis.

To mitigate this risk, veterinarians and horse owners must understand the health problems at play and effective strategies for weight loss. Ingrid Vervuert, DMV, of the Institute of Animal Nutrition, Nutrition Diseases and Dietetics and the Faculty of Veterinary Medicine at the University of Leipzig, in Gemrany, described these approaches at the 2016 American Association of Equine Practitioners Convention, held Dec. 3-7 in Orlando, Florida.

Perception is Key

While horse owners might understand and recognize the problems with obesity, many don’t realize when their own horses are overweight. Obesity develops due to excessive energy intake, poor management and feeding practices, and lack of exercise, said Vervuert. Some horses and ponies are “easy keepers,” meaning they maintain weight with very little supplemental feed. Overfeeding easy keepers undoubtedly leads to weight gain.

Metabolic Consequences

Energy that horses and ponies do not burn off is stored as fat. Fat tissue acts as an endocrine gland capable of secreting inflammatory proteins (cytokines), hormones (leptin and adiponectin), and enzymes for lipid (fat) regulation.

Insulin is a hormone that signals cells in tissues, like muscle and liver, to absorb glucose from the blood stream and store it for later use as energy. Insulin resistance is a condition where the cells have a decreased response to insulin. More and more insulin is required to achieve glucose absorption (An analogy is that insulin must “shout” at resistant tissues to get a response, rather than speak in a normal tone). Insulin resistance is one of the biggest concerns veterinarian have for in overweight animals.

Feeding Management

Owners can quickly and easily get their horse started on the path to weight loss by removing feed or reducing energy intake. Be careful, however, not to starve the horse but, rather, decrease forage intake to 1-1.5% of ideal body weight, said Vervuert. Soak forage for 30-60 minutes to remove excess starch and sugar, and eliminate grain concentrates from the diet. Add a protein-fortified ration balancer to the horse’s diet to supply the vitamins and minerals necessary for basic health.

Grazing muzzles are essential for obese horses on pasture if a drylot is not available. However, reducing forage intake can exacerbate behavioral problems due to boredom. Consider using haynets or slow-feeders to extend chew time and time spent foraging.

Healthy weight loss is gradual. Ideally, you’ll want your horse to lose 1% of his or her body weight per week. More is too fast, but slightly less is okay. Owners must understand body condition scoring, how to weigh a horse properly, and how to keep track of changes over time to manage these horses optimally.

Take-Home Message

Obesity in horses is a bigger problem than most owners tend to realize. To help an overweight horse or pony lose weight, remove grain concentrates from the diet, prevent pasture access, and feed a good protein-fortified ration balancer. Haynets and enrichment toys can help reduce behavioral problems brought on by boredom. Weight loss happens slowly, so keep track of changes and be patient, said Vervuert.