What Your Horse’s Hunger Hormone Can Tell You
If you have ever wondered whether your older horse or your pony has different hunger-hormone patterns than other equids, new research offers an early clue. A preliminary study published in BMC Veterinary Research examined active ghrelin in 35 horses and ponies and found a 19% drop after feeding (p = 0.001), a positive association with age, and higher pre-prandial active ghrelin in Welsh ponies versus other breeds (p = 0.0003). This is early-stage research, but it adds useful baseline data on how ghrelin varies across healthy equids.
The study looked at how this appetite hormone behaves in healthy horses and ponies, setting groundwork for future studies on equine feeding physiology across age and breed groups.
Why Appetite Hormones Matter in Horses
Ghrelin (pronounced GREL-in) is often called the “hunger hormone.” In simple terms, it is a chemical signal your body — and your horse’s body — releases to say “I’m hungry.” When the stomach is empty, ghrelin levels rise. After a meal, they fall. This up-and-down pattern helps regulate how much an animal eats and how energy is used.
In horses, this signaling system matters a great deal. Horses are natural grazers, designed to eat small amounts of forage almost continuously. Many health problems in horses and ponies — including obesity and laminitis (a painful hoof condition) — are linked to disruptions in how the body manages energy and appetite. Understanding the hormones behind those processes can help owners and veterinarians manage horses more effectively.
Before this study, very little was known about how ghrelin works specifically in horses and whether it behaves the same way across different ages and breeds. That is the gap this research set out to address.
How the Study Was Conducted
Researchers measured ghrelin in 35 horses and ponies that showed no signs of metabolic disease — meaning these were healthy animals at the time of the study. The team measured active ghrelin before and after feeding, assessed associations with age, and compared pre-prandial concentrations by breed grouping.
- Active ghrelin levels in the blood: Measured before and after feeding to see how the hormone responded to a meal
- Ghrelin receptor expression in tissues: Researchers identified receptor isoforms in equine tissue samples
The study also assessed whether age was linked to ghrelin levels, and whether fed versus pre-prandial state changed concentrations.
What the Study Found
Ghrelin Dropped After Feeding — as Expected
The study confirmed that active ghrelin in the blood fell after horses were fed. This mirrors what happens in people and other animals. It is a sign that ghrelin is working as a hunger signal in horses: levels rise when the stomach is empty and fall after a meal.
This may seem like a small finding, but confirming that horses follow this same basic pattern is an important step. It validates that ghrelin-based measurements can be useful tools when studying equine feeding behavior and metabolism.
Older Horses Had Higher Ghrelin Levels
One of the more interesting findings was the link between age and ghrelin. Horses that were older tended to have higher active ghrelin levels overall. This is early-stage data, and the study does not explain exactly why this happens, but it suggests that the hunger signaling system may change as horses age — similar to the way metabolism shifts over a lifetime in many animals.
For owners of older horses, this is worth noting. It does not mean older horses necessarily eat more or need more feed. But it does hint that their internal hunger signals may behave differently, which could be relevant when thinking about body condition management in senior horses.
Pre-Prandial Ghrelin Was Higher in Welsh Ponies
The study reported higher pre-prandial active ghrelin concentration in Welsh ponies versus other horse and pony breeds (p = 0.0003).
This is a group-level observation from a preliminary dataset, not proof that any single horse or pony will have a specific feeding response. It does, however, identify a measurable breed-associated pattern worth testing in larger studies.
Again, this is preliminary. The researchers are not drawing firm management conclusions from this data, but it opens an important line of inquiry.
What This Means for Horse and Pony Owners
A First Step, Not a Feeding Rule
It is important to be clear about what this study is and is not. It is a foundational study — one that measures and describes how ghrelin behaves in healthy horses and ponies. It is not a clinical trial, and it does not directly test whether changing a horse’s feeding routine based on ghrelin would improve outcomes. The authors describe this as early physiology research, not a set of management recommendations.
That said, the findings are a meaningful step forward. They confirm that:
- Ghrelin responds to feeding in horses the way you would expect a hunger hormone to
- Age appears to influence ghrelin levels in horses
- Pre-prandial active ghrelin was higher in Welsh ponies than in other breeds in this sample
These are building blocks for future research that may eventually help veterinarians and owners make more informed decisions about nutrition across different horse types.
Practical Takeaways for Now
While the study does not change day-to-day feeding advice, it does reinforce a few things that experienced horse owners already know:
- Age matters. Senior horses and young horses are not the same metabolically. Regular vet check-ups and body condition scoring become more important as horses age.
- Breed findings are preliminary. This study reported higher pre-prandial active ghrelin in Welsh ponies, but larger studies are needed before drawing management conclusions.
- Watch for metabolic warning signs. Unexplained weight gain, a cresty neck (a fat deposit along the top of the neck), or recurring laminitis can all be early signs of metabolic imbalance. Talk to your vet if you notice these.
When to Consult Your Veterinarian
If you are managing a horse or pony with weight issues, a history of laminitis, or suspected metabolic disease — such as Equine Metabolic Syndrome or PPID (sometimes called Cushing’s disease, a hormonal condition common in older horses) — discuss a metabolic workup with your vet. Blood tests can assess relevant hormones and help guide an appropriate feeding plan.
This study focused on healthy animals, so the findings may not directly apply to horses already dealing with metabolic conditions. That is another reason to work with a professional for those cases.
Study Limitations
This is preliminary research, and the authors are clear about that. The study measured ghrelin in a specific group of horses and ponies without metabolic disease, so results may not represent the full range of equine populations. The sample size of 35 animals is modest, and the study did not follow horses over time — so it describes a snapshot rather than how ghrelin changes as individual horses age.
The finding that ghrelin is positively associated with age is observational. It shows that the two are linked, not that aging directly causes ghrelin levels to rise. Future research will need to explore what drives these patterns and whether they have practical implications for feeding management across different breeds and life stages.
The Bottom Line
A preliminary study of 35 healthy horses and ponies found that active ghrelin dropped 19% after feeding, was positively associated with age, and was higher pre-prandially in Welsh ponies than in other breeds. This is early-stage science and observational, not a feeding rule.
For now, keep treating your horse as an individual. Age, breed, and body condition all matter when making feeding decisions, and your veterinarian is your best partner in building a nutrition plan that fits your specific animal.
This article summarizes peer-reviewed research for educational purposes. Always consult with your veterinarian for personalized advice about your pet’s health and behavior.