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