Some horses hold weight all year. Others seem to drop condition every winter, or melt off pounds in the heat of summer. If your horse loses weight with the seasons, the cause is often the season itself, plus a few things you can manage.
Let's look at why winter and summer both put pressure on weight, and how to keep condition steady through the year.
Winter: the body burns more to stay warm
Cold weather raises a horse's calorie needs. The body burns energy to stay warm, so the same ration that held weight in fall may fall short in deep winter. A thick coat can also hide the loss until you put your hands on the horse.
Here is what helps most in winter:
- Feed more forage, not just more grain. Digesting hay produces heat from the inside, so extra good hay is the best winter warmer.
- Check water. Horses drink less when water is icy. Less water means less feed intake, so keep water clean and not freezing.
- Use shelter and blankets wisely. Blocking wind and wet helps a horse spend fewer calories on staying warm.
- Put hands on the horse. Body condition score under the coat every couple of weeks so you catch loss early.
Summer: heat, sweat, and appetite
Summer pulls weight off in different ways. Heat can cut appetite, so the horse simply eats less. Hard work in heat burns more, and heavy sweating loses both water and minerals called electrolytes.
What helps in summer:
- Feed in the cooler hours. Many horses eat better in the early morning and evening.
- Keep cool, clean water available. Hydration drives appetite and recovery.
- Replace electrolytes lost in sweat. Heavy sweating loses minerals, so ask your vet about a sensible electrolyte plan for hot months.
- Mind the pasture. Grass quality changes through summer, and a baked-off pasture may offer fewer calories than it looks.
The mineral angle
Sweat does not just carry water. It carries minerals out of the body. Over a hot, hard-working summer, those losses add up. That makes mineral status worth checking, especially for horses in heavy work or those that always seem to struggle in one season.
A hair mineral analysis screens trace minerals and heavy metals and gives you a baseline to track across seasons. It is a screening and tracking tool, not a diagnosis, so pair it with sensible feeding and your vet's input.
Curious how your horse's minerals look heading into a tough season? Order a hair mineral analysis test kit and set a baseline you can track.
When to call your vet
Seasonal change should be gradual. Call your vet if you see:
- Sharp weight loss that does not match the weather
- Loss that continues after you have added feed and shelter
- Other signs like dullness, going off feed, or loose manure
If a horse keeps losing weight after you have managed the season, the season is not the whole story.
A simple winter feeding plan
Winter is about calories and warmth. Build the plan around forage.
- Feed more hay. Digesting hay makes heat from the inside. It is the best winter warmer.
- Keep water from freezing. Cold or icy water cuts how much a horse drinks and eats.
- Block wind and wet. Shelter and a blanket help a horse spend fewer calories on staying warm.
- Check under the coat. A thick coat hides weight loss, so use your hands.
A simple summer feeding plan
Summer is about heat, water, and minerals. Keep your horse cool and hydrated.
- Feed in cooler hours. Many horses eat better in early morning and evening.
- Offer cool, clean water. Good water drives appetite and recovery.
- Replace electrolytes. Heavy sweat loses minerals, so ask your vet about a plan.
- Watch the pasture. A baked-off field may hold fewer calories than it looks.
Track it through the year
The best defense is a habit. Check your horse the same way all year.
Use a weight tape once a month. Put your hands on the ribs under the coat. Snap a photo from the same spot. Small notes catch a slow loss before it becomes a big one.
Common questions
Why does my horse lose weight every winter?
Cold weather raises calorie needs, and icy water can cut intake. More good forage, reliable unfrozen water, and shelter usually hold condition. Check under the coat often.
Why is my horse losing weight in summer heat?
Heat can lower appetite, work burns more, and sweat loses water and minerals. Feed in cooler hours, keep water cool, and replace electrolytes with your vet's guidance.
Do horses need more minerals when they sweat a lot?
Heavy sweating loses electrolytes and other minerals, so hard-working horses in heat often need support. A hair mineral screen can help you track status over the seasons.
Seasonal weight loss is usually about calories in winter and heat in summer, plus the minerals lost in sweat. Manage the season, then check the nutrition side. Order a hair mineral analysis test kit, and see the complete guide to weight loss in horses if the loss does not match the weather.
Sources:
Merck Veterinary Manual. Nutritional Requirements of Horses and Other Equids: https://www.merckvetmanual.com/management-and-nutrition/nutrition-horses/nutritional-requirements-of-horses-and-other-equids
Merck Veterinary Manual. Nutritional Diseases of Horses and Other Equids: https://www.merckvetmanual.com/management-and-nutrition/nutrition-horses/nutritional-diseases-of-horses-and-other-equids
University of Maine Cooperative Extension. Equine Facts: Body Condition Scoring for Your Horse (Bulletin 1010): https://extension.umaine.edu/publications/1010e/