Four Keys to Equine Weight Loss

Ever heard this before? “That horse needs to go on a diet!” or “Put him in a dry lot and give him only a small amount of hay!” The advice is usually well-intentioned, but if it’s meant to “starve” the horse, it’s wrong. 

Experts agree that severely restricing the amount your horse eats won’t promote weight loss. It will make him ill, possibly worsening insulin resistance and/or causing hyperlipemia (elevated blood triglycerides and impaired liver function). 

The trick to successful, healthy weight loss is to feed your horse properly. Allow him the calories he needs to lose weight and ensure you’re giving him adequate nutrition and exercise. It’s not difficult.

To get started, keep these four points in mind:

1. Reduce stress: An empty stomach can stress your horse. Horses were meant to graze all day, and the equine digestive tract is designed to have forage flowing through it at all times. So, unless there’s no other choice, feed frequent small meals of hay. The goal is to ensure the horse has little or, preferably, no time without some hay. That’s why slow feeding devices are so beneficial—they limit how much hay a horse can eat at one time, so they can’t gorge themselves, but the horse also feels like he has constant access to hay (we have some in a field trial now; stay tuned!). 

2. Reduce calories and non-structural carbohydrates (NSC): Analyze your hay to ensure it is a low NSC (12% or less) hay (see January 2013) before you begin the diet. NSC is the sugar, fructan, and starch content of the hay. If you have at least a one-month supply of hay, it’s worth testing, especially if your horse is insulin-resistant (IR) or IR-prone. The price of hay analysis is generally reasonable. 

Ideally, you will analyze your pasture, too, but the NSC of fresh grass can vary depending on the time of day, amount of sunlight, night time temperatures, and stress the grass experiences from drought or overgrazing, so this isn’t always feasible. 

With turnout, grazing muzzles may be beneficial for horses that accept them calmly. Some horses won’t. If you want to try one, we recommend the Best Friend Grazing Muzzle (, 800-681-2495). Once your horse accepts the muzzle, it naturally limits how much grass the horse can pull into his mouth at once, therefore reducing his grass intake. We advise limiting turnout in a muzzle to four hours a day. After that time, remove the horse from the grass, remove the muzzle, and provide hay.

3. Add optimal antioxidants: Body fat increases inflammation in the horse’s body. Antioxidants help reduce that inflammation (see main story). There are a number of commercial products available that are high in antioxidants (see the May 2013 for more on antioxidants). Note: If you need a “carrier feed” for adding supplements, choose one that is low in sugar and starch, such as molasses-free beet pulp or hay pellets, and feed the smallest amount needed for the purpose.

4. Exercise: Exercise does three things: It burns calories, builds muscle (which is more metabolically active than fat), and causes the tissues to become more sensitive (less resistant) to insulin. Turnout is not adequate exercise for weight loss. Longeing, riding, driving, even hand walking 10 minutes each day will make a significant difference.

Dieting Methods

No one diet plan fits every barn perfectly, and recommendations among veterinarians vary. The decision on which to use is yours.

The traditional method is to cut concentrates and feed hay at a rate of 1.5% of ideal bodyweight. This means if your horse weighs 1,100 lbs., you would drop his hay intake to 15 lbs. per day, usually providing the hay in a couple of meals per day. If that didn’t promote a slow, steady weight loss (as in no change in the weight tape after 30 days), the plan is to further reduce hay to 10 lbs. per day (1% of ideal bodyweight).

A newer method that is gaining acceptance—and makes sense when you consider metabolic rate—is to keep hay in front of your horse at all times. That said, you must be certain that the hay is low-starch, low-sugar, and low-calorie. The theory is that if the horse has constant hay, he won’t stress about where the next meal is coming from and try to eat everything in front of him as soon as it’s served. With time and the assurance that he will always have hay, he will eventually self-regulate his intake and maintain a normal body weight.

Regardless of which method you choose, if the horse isn’t losing weight, consult your veterinarian for a diagnostic workup immediately to rule out look-alike problems. (See September issue for a discussion of Cushing’s vs. metabolic syndrome vs. insulin resistance.) 

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