Horse Care

Best Feed for an OTTB: An Art and a Science

OTTB horse
Written by Natalie Gasper

Spoiler alert: there’s no one best horse feed.

Not for OTTBs (Off-Track Thoroughbreds), anyway. They have unique caloric and energy needs that vary based on a range of environmental factors and their current body condition (if you’re not familiar, check out this guide).

OTTBs tend to thrive on diets that are higher in fat and protein than in carbs and sugar. Offer at least 2% of the horse’s weight per day (or about 20lbs) in high-quality forage. Supplements, like salt and biotin, can be great additions to your OTTB’s diet, as can canola oil, if your horse needs to gain weight.


Equine Nutrition – The Basics

Equine nutrition can be a scary topic for both new and experienced horse owners alike. Throw an OTTB in the mix, and all bets (intentional) are off.

The simplest version of nutrition comes down to the big three: fats, protein, and carbohydrates (sound familiar)?

How much of which your horse needs depends on their age, breed, and level of training, as well as their current body condition. They also have certain vitamin and mineral needs, as well as certain amounts of water and electrolytes.

The Merck Veterinary Manual gives an in-depth breakdown of all the components that go into your horse’s diet.

If this area feels overwhelming (I, too, have gotten lost down the nutrition rabbit hole), trust that a combination of a commercial feed, forage, and salt will keep your horse happy and healthy.

What kind of hay/forage is best for OTTBs?

Thoroughbreds can be a difficult breed when it comes to gaining (or just maintaining) weight. I’ve found the best combination to be an alfalfa mix (my preference is alfalfa and orchard), as much grazing time as possible, and supplementing with soaked beet pulp (molasses-free) as needed.

What is the best grain for an OTTB?

Aim for a grain that’s higher in fats and protein than in starches. Avoid sweet feed, as that tends to give an OTTB an unwanted “boost” during workouts.

According to equine nutritionist Elisabeth Chizek, many performance feeds (like Purina Impact Professional Performance) offer the right combination of fat/protein/sugars.

purina horse impact

See Purina Impact feed at Amazon

What are good supplements for an OTTB?

If you use a commercial feed, they are balanced, meaning they provide your OTTB with most of their mineral and vitamin needs (if you’re in doubt, consult with your veterinarian).

Regardless, many OTTBs will benefit from salt or electrolyte supplementation. If you opt for salt, choose the non-iodized kind (which you can find for super-cheap at your local grocery store).

Ready our full article on the best OTTB supplements.

What are the best treats for an OTTB?

The best treat is the one they’ll eat! When I bought my first OTTB, he had no idea what an apple or a carrot was. Once he learned to eat them, he loved them.

You can also go with peppermints or peppermint training treats (great if you plan to give a lot), or even make some delicious horse cookies.

horse peppermint treats

Click to see peppermint treats at Amazon

Help! My OTTB Needs To Gain Weight

There’s nothing more terrifying than an OTTB that struggles to gain weight. It’s easy to blame yourself and start buying more expensive feeds or exotic supplements.

OTTBs are sensitive to everything, from stress and training to new environments, and this translates to weight gain (and weight loss) problems.

If you’re ruled out any possible medical reasons (like ulcers or parasites) with your vet, then time, patience, and the right combination of hay, grain, and supplements will do the trick.

What can I feed to put weight on my OTTB?

Lots of forage and fat is the way to go. According to LSU School of Veterinary Medicine, a healthy adult horse eats about 2-2.5% of its body weight daily.

If you have a 1200lb horse, this means 24 lbs of roughage per day, and that’s just to maintain weight.

For my OTTB, I found that supplementing with molasses-free beet pulp was the best way to help him gain weight. Other riders I know have used rice bran or oil.

How do I keep weight on my OTTB during the winter months?

Make sure your horse is getting the right amount of calories from his regular feed and hay (it’s just as easy to underfeed as to overfeed). If he’s getting what he should, consider adding a high-fat supplement (like Purina Amplify), beet pulp, or canola oil.

Horse racing

Ulcers in OTTBs

Let’s face it: OTTBs have ulcers. If they don’t have them, they’re likely to get them. But ulcers aren’t as scary as they sound. They’re relatively easy to prevent and even to treat.

The signs can be subtle, but ulcers can be easily managed.

How do you treat ulcers in a Thoroughbred?

There are two components to this: prevention and treatment.

Ulcers are usually a man-made problem. Keeping a horse confined to a stall, feeding only twice per day, no contact with other horses, and high levels of training or competition are just a few of the factors that contribute to ulcers.

Maximizing turnout, minimizing grain, and giving your horse free-range access to quality forage are all great ways to prevent ulcers.

A common treatment for a horse with ulcers is Omeprazole. This medicine will help eliminate ulcers, but it’s very important to follow some of the preventive measures above so they don’t come back.

If you’re looking for more information on ulcers, this is a great resource.

Frequently Asked Questions

Horses racing

Image courtesy of Canva

Q: What do top racehorse trainers feed?

Whole oats are a common answer, along with vegetable oil, flaxseeds, and plenty of top-quality forage. Some trainers also supplement with bran and additional vitamins and minerals.

A racehorse’s diet is carefully structured. They burn thousands of calories, lose lots of water weight (sweat), and need consistent access to energy in their bodies to perform at their best.

Generally, what a Thoroughbred eats when they’re racing should NOT be consumed once they’ve retired. With a different career and training routine, oats and a high-fat, energy-dense diet is no longer necessary.

Q: What are the best hoof supplements for OTTBs?

Dozens of hoof supplements are available to choose from. Farrier’s Formula is a popular one that you’ll find in most barns.

The key to choosing the best hoof supplement for your OTTB? Biotin.

Research shows that horses need around 20 mg of biotin per day to improve overall hoof quality. In this area, consult with your farrier. They’ll likely have a favorite supplement and can also recommend helpful oils or paints.

farrier's formula

Click to see it at Amazon

Q: What should I feed a Thoroughbred in light work?

This varies widely and depends largely on your horse. Typically, feeding less of what they usually get works fine (though be sure to cut back on their grain first).

When my OTTB was in light work for three months after surgery, I replaced his grain with a ration balancer but made sure he had plenty of hay. Cut out any fat supplements or oils and keep a close eye on his body condition (it can change in the blink of an eye).

Q: What are common challenges in transitioning an OTTB to a new diet?

Brown horse with bridle looking straight ahead

Image courtesy of Canva

A diet tailored for an actively racing Thoroughbred is generally low in forage and high in energy-dense nutrients to support the horse’s metabolism while racing. However, a horse no longer racing needs the reverse: high forage and lower energy-dense nutrients. 

Compared to other breeds, Thoroughbreds tend to have higher metabolisms and burn through more calories, so they may naturally require higher energy diets than Quarter Horses. There does need to be a reduction in calories when the horse’s activity level decreases.

Changing a horse’s diet can also result in behavioral changes, including increased lethargy or restlessness. Remember, any changes to a horse’s diet should be done slowly to prevent GI issues, including diarrhea or ulcers. 

Last, if you have concerns about your OTTB, don’t hesitate to contact your veterinarian.

Q: How can I gradually introduce a new feed to my OTTB?

Start by mixing a very small percentage of the new feed with the horse’s previous feed. 10% per day is a good starting point. Carefully monitor your horse for possible adverse reactions to the new feed and consult your veterinarian with concerns. 

Gradually increase the percentage of new to previous feed over 10-14 days until your horse consumes 100% new feed. It’s also helpful to start feeding with small portions. This may mean feeding more frequently at first.

Some racehorses have limited access to pasture, and making this introduction should also be done slowly to prevent GI upset.

It’s always best to consult with an equine nutrition professional to develop a plan to safely bridge the gap between the old and new diets.

Q: What signs can you use to determine whether your OTTB’s diet is adequate?

Assessing body condition is one way to determine whether your OTTB’s diet is adequate. Your horse should not have excessive fat pads, nor should you be able to clearly see every rib.

Behavior and energy level are other ways to assess your horse’s diet. An excessively sluggish horse may need additional nutrients, while a spunky one may benefit from a slightly different diet.

Watching for signs of digestive issues can also give you critical insight into whether your horse’s current diet adequately meets its needs. If you have questions or concerns, consult your veterinarian for additional insight.

Parting Thoughts

Like with any breed, what works for one OTTB might not work for another. The right dietary choices depend on the horse’s environment, level of stress, and amount of training.

You’ll take a different approach to help your OTTB gain weight than you do to maintain his weight.

One thing I learned the hard way is that a good workout routine is just as important as the right diet. Instead of staring at your horse’s ribs, focus on helping him feel comfortable in his environment and on building muscle.

Sooner or later, your OTTB will look as fabulous as he feels.

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About the author


Natalie Gasper

Nancy loves retraining off the track Thoroughbreds and working with her dogs!