How To Feed Your Newly Adopted Mustang

How To Feed Your Newly Adopted Mustang

Mustangs live in a social setting eating a varied array of wild plants that are quite different from the quality hays we typically feed domesticated horses, and certainly he will have had no experience consuming grains.

Photo: iStock

Q. I recently adopted a Bureau of Land Management (BLM) mustang. Are there any special dietary considerations I should keep in mind as my gelding transitions to domestic life?

S.K., Oregon

A. BLM mustangs are truly special horses. I’ve had a few as clients but was also lucky enough to own one when I was in graduate school. He came out of the Twin Peaks Herd Management Area as a 2-year-old, and I bought him as a barely started 4-year-old and trained him as a kid’s event horse.

When mustangs come off the range, I would argue that they are more in sync with how horses evolved to live and eat than any domesticated horse. Remember that horses evolved roaming large distances over varied terrain eating native grasses and other plants with low nutritional value. As a result 60% of the horse’s digestive tract volume is dedicated to forage fermentation and—because of that almost constant feed consumption whether eating or not—horses constantly secrete stomach acid and bile. While this way of living is far from the domesticated horse’s reality of most domesticated horses, it has been the reality for your BLM mustang until he came in to the holding pens prior to his adoption.

I encourage all my clients to keep this evolutionary history in mind when thinking about feeding horses, but it’s particularly important for your mustang. He has lived in a social setting eating a varied array of wild plants that are quite different from the quality hays we typically feed domesticated horses, and certainly he will have had no experience consuming grains, even traditional grains such as oats.

Alfalfa's Benefits 

In the holding pens, alfalfa is generally fed as it is typically easily available and cheaper than grass hay in the Western states. Initially, consider continuing feeding your mustang alfalfa and don’t make changes until he is settled in his new environment. To keep your horse safe and contained, when you first adopt, the BLM requires you to keep your new mustang in a small space with high fencing (so he can’t escape). I imagine that at least initially this means your horse will live alone. Your horse might find this management change and solitary life stressful (although he might not show it), which puts him at risk of developing equine gastric ulcers.

Research has shown that feeding alfalfa (even small amounts) will help buffer stomach acid and could help reduce ulcer risk. Down the road transitioning to a grass hay and some alfalfa or all grass hay would be ideal as it will probably mean you can feed more total pounds of hay which is not only good for digestive health but mental health as well. In the meantime try to keep hay in front of him as much as possible and over time consider training him to eat from a slow feeder which helps mimic natural grazing.

Strategies for Easy Keepers

While there’s always an exception to the rule (mustangs are still horses after all), mustangs are generally very easy keepers an—once settled in to your routine—you might find he gains weight on rations when other horses would not. By using slow feeders you can create a scenario of restricted free-feeding, and he will probably self-regulate his hay intake to about 2% of his body weight. If he’s one of the few horses that can’t self-regulate, you can use a slow feeder to make a reduced hay ration (no less than 1.5% of his body weight) last longer, which might benefit his digestive and mental health.


Make sure your mustang has salt (loose or in block form) available at all times. Be aware that he might not willingly take feed from a bucket (remember: he’s never seen one before!), which might reduce his salt consumption if you have loose salt in a bucket. Using a wide shallow pan might work better.

More on Buckets and Mustangs

A note of experience: I made the mistake when I first got my mustang of putting some alfalfa pellets in a bucket thinking that this might help generate a bond between us. Feed buckets had always been seen as a good thing by every other horse I had owned. Not my mustang! He wouldn’t put his head in a bucket. When I thought about this, it was obvious: First of all he had never seen a bucket, or hay pellets for that matter. Second of all, why would a flight animal that relies on sight put its head in a bucket that reduces its ability to see? He did eventually get over this bucket phobia.

While this is one of those funny sorts of quirks you might run in to with your mustang the bucket issue can be a real issue if your barn only provides water through water buckets, or small automatic waterers. The sound of the automatic water refilling can easily scare an already-on-edge mustang. Coupled with not understanding buckets in general, this might lead to inadequate water consumption. It’s likely you’re your mustang has encountered water troughs in holding pens or on the range, and using a trough is preferable until he can be taught to understand buckets and automatic waterers.

Make sure he cannot knock the trough over, though. Once over his fear he might want to play with the water as if they’re puddles, streams, or ponds!


At some point, just as with any other horse, you’ll need to add a source of vitamins and minerals and possibly quality protein to your mustang’s diet. A commercially available ration balancing feed is a good choice due to their low calorie content. Or, an even lower-calorie supplement fed in some hay pellets would be a good option.

Increasing Calories

Once in more active work, if you find he needs extra calories, increasing his forage intake is an ideal solution. Alternatively using the low-starch feeds on the market would be a wise choice but be certain that you feed at the full level set by the manufacturer, otherwise you mustang (and any horse for that matter) won’t get the full benefit of the mineral and vitamins and the diet will likely be deficient or unbalanced.


If you are in a situation where grass pasture is available, and once you have the all clear to keep him in space bigger than his original pen, he might enjoy safe turn-out time with a group of other horses. Keep in mind that our improved pastures are very different than the grasses he ate on the range. Try to keep him out of pastures that are stressed (which can cause higher sugar content) due to cold weather, poor irrigation or fertilization practices, and learn about safe times of day to graze, because as he might be more sensitive to sugars in the grass than some other breeds.

Take-Home Message

With time, patience, and common sense you should have a lot of fun with your mustang. Mine taught me more about equine behavior and how to really be in the world than any other horse I have been involved with. He loved his person, and he still has a special place in my heart. I hope your new partner finds his way in to yours.

Have you ever adopted a BLM mustang or other feral horse? Tell us about your mustang’s nutrition experiences or challenges below in the comments!

About the Author

Clair Thunes, PhD

Clair Thunes, PhD, is an independent equine nutrition consultant who owns Summit Equine Nutrition, based in Sacramento, California. She works with owners/trainers and veterinarians across the United States and globally to take the guesswork out of feeding horses. Born in England, she earned her undergraduate degree at Edinburgh University, in Scotland, and her master’s and doctorate in nutrition at the University of California, Davis. Growing up, she competed in a wide array of disciplines and was an active member of the United Kingdom Pony Club. Today, she serves as the regional supervisor for the Sierra Pacific region of the United States Pony Clubs. As a nutritionist she works with all horses, from WEG competitors to Miniature Donkeys and everything in between.

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