In North America, it is estimated that up to 51% of horses are overweight and up to 8% are obese [1][2][3]

Horses become overweight from a combination of factors, including insufficient activity and consuming excess calories.

A horse’s energy requirements depend on many factors such as age, breed, genetics, exercise, and life stage. [4] Some horses are easy keepers and are prone to gaining weight quickly.

Easy weight gain may be a sign of metabolic syndrome and hyperinsulinemia which is the leading cause of laminitis. Being over-conditioned can affect performance, joint health and soundness. [5]

If your horse is overweight, work with your veterinarian and an equine nutritionist to formulate a feeding and management plan to support healthy weight loss. This article will discuss key tips for feeding overweight horses to lose weight.

How to Tell if Your Horse is Overweight?

Body condition scoring (BCS) is a method of estimating your horse’s subcutaneous adipose tissue (body fat that accumulates directly under the skin).

The BCS scale rates your horse’s body condition from 1 to 9, with a score of 1 considered emaciated (very thin) and 9 considered very obese. [6]

A healthy horse should score a 5 on the 9-point scale. However, a score of 4 or 6 may also be acceptable, depending on the horse’s life stage, age and any health conditions it may have.

A score of 7 is considered overweight, and scores of 8 and 9 are considered obese. [4] [6]

Assessing Body Condition

As horses gain weight, fat accumulates over the horse’s whole body and in these six areas: [6]

  • Over the tailhead
  • Over the rump
  • Along the withers
  • Along the neck
  • Over the ribs
  • Behind the shoulder

By visually assessing and palpating these key areas, you can understand where your horse falls on the 9-point scoring system.

Follow the steps in this Guide to Body Condition Scoring your Horse to determine whether your horse is overweight and needs to lose body condition.

Studies show that horse owners often underestimate their horse’s body condition, particularly for overweight horses. [1] Ask your veterinarian or an equine nutritionist for a second opinion on your horse’s BCS score.

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What Causes Overweight in Horses?

Any horse can become overweight or obese when their energy intake is not balanced with their energy expenditure. However, many animal- and environment-specific risk factors can increase a horse’s likelihood of becoming overweight or obese.

Risk factors for being overweight can include: [1][7][8][9]

  • Feed availability: Providing excess food, above requirements, can result in weight gain.
  • Feed type: Providing energy-dense forages, grains, brans, and commercial feeds can contribute to weight gain.
  • Breed: Breeds genetically predisposed to metabolic syndrome such as ponies, minis, donkeys, mules, Arabians, Morgans, Spanish breeds, Canadians and others gain weight more easily while full size drafts and “hot” breeds like Hackneys and Thoroughbreds are not genetically predisposed.
  • Exercise level: Horses at maintenance (pleasure riding or no riding) are more likely to be overweight than competition horses in regular exercise.
  • Management: Horses maintained exclusively on lush pasture are more likely to be overweight than horses kept in stalls with daily turnout.
  • Season: Access to free-choice pasture in the spring and summer is associated with a greater risk of obesity.
  • Age: Young animals are less likely to be overweight unless they are being overfed and confined. Once growth essentially stops, weight gain can become a problem. On average, this occurs around 4 years of age. The onset of weight gain often coincides with the development of metabolic syndrome and, if not properly fed, laminitis.

Why Should I be Concerned if my Horse is Overweight?

It is important to maintain your horse at a healthy body condition.

Overweight and obese horses are more likely to have metabolic syndrome or Pituitary Pars Intermedia Dysfunction (PPID) because metabolic syndrome predisposes to weight gain. If hyperinsulinemia is not controlled, laminitis will ensue.

Overweight horses are also at risk of several health complications including, but not limited to: [1][4][11][12][13][14][15]

  • Arthritis
  • Hyperlipidaemia
  • Reduced reproductive performance
  • Strangling lipomas in the intestines
  • Problems with thermoregulation
  • Exercise intolerance

Feeding the Overweight Horse

Feeding practices play a key role in both the treatment and prevention of obesity.

If your horse is overweight, it’s important to reduce the energy content of their diet to create a calorie deficit. Follow the tips below on forage selection and feed provision.

Increasing your horse’s activity level by introducing appropriate exercise can also promote weight loss and improve metabolic health.

For personalized help with managing an overweight horse, submit their information online to receive free diet evaluation. Our nutritionists can help you identify factors contributing to your horse’s weight gain and formuate a weight loss plan for your horse.

1) Eliminate Grains and Commercial Feeds

To lower your horse’s caloric intake, slowly decrease or eliminate grains and commercial feeds from their diet.

Grain-based complete feeds and sweet feeds provide a lot of additional calories that most horses don’t need.

These feeds also contain high amounts of sugars and starch, collectively called hydrolyzable carbohydrates (HC). HC is the portion of non-structural carbohydrates (NSC) which is digestible in the small intestine and contributes to the insulin response. NSC also includes fructan, which contributes to calories when it is fermented but does not trigger insulin release.

Feeding excess HC also has negative implications for digestive health, and behaviour. Sugar and starch are rapidly digested and absorbed by the horse’s body, increasing blood sugar levels.

This triggers the release of insulin, a hormone that tells the body to store glucose (sugar) as glycogen in the liver and muscle cells. Additional energy will be stored as fat.

Horses with insulin resistance in PPID or EMS have exaggerated insulin responses to HC. These high insulin levels can cause laminitis.

Removing excess calories by transitioning from commercial feeds and grains to a forage-based diet is an easy first step to helping your horse lose weight.

2) Reduce Other Energy Sources

Brans and fat supplements are good energy sources for hard-keepers, horses in heavy work, or horses requiring extra calories to maintain weight.

However, these feeds should be reduced or removed from the diets of overweight horses.

Fat supplements and oils are particularly energy-dense, providing 9 kilocalories (kcal) per gram of feed.

If a carrier is needed for supplements, consider using beet pulp which is low in sugar and starch. It can hold up to 4X its dry weight in water so a small amount can go a long way.

3) Feed a Forage-Based Diet

Forage should make up the bulk of your overweight horse’s diet. Hay is high in fibre, which is fermented by microbes in the hindgut to produce volatile fatty acids (VFAs) – the ideal energy source for horses.

Feeding forage supports a healthy gut microbiome and enables the horse to express natural grazing behaviours, reducing the prevalence of stereotypies such as stall weaving and cribbing.

Forages also take longer for your horse to chew than concentrates, extending feeding time and reducing ulcer risk.

Hay is lower in energy than haylage or pasture, making it a better choice for overweight horses. [3] Feeding low-quality forages, such as late-harvest hay can also