Help for Horses Losing Weight Through Winter
By: Dr. Lydia Gray | Updated March 21, 2025 by SmartPak Equine
Question #1:
"I have a paint horse that is 30 years old and he has lost weight and is looking bad despite being on feeding supplements. Is there any one particular supplement that will help him gain weight? I know he is an old horse but I have had him for about 15 years and gotten attached to him and don’t want to do anything to hurt him in any way. I know he hasn’t much time left but I don’t want him suffering."
Question #2:
"What is the best supplement to put weight on a horse? We have had her on Fat Cat and she still is not putting any weight on. She is 5 yr old mare that is used in college rodeo. She gets equine senior feed, plus a big amount of grass/alfalfa mix. She is ridden at least 5 times a week. Any help would be appreciated."
Over the past few weeks, I’ve been inundated with questions about how to put and keep weight on horses. It’s especially critical as we head into winter and possibly a hay shortage, depending on what part of the country you live in.
I’ve included two questions in this entry because they represent two common but different reasons for horses to be thin:
- old age
- athletic activity
Evaluating Medical Causes of Weight Loss in Horses
The first thing I recommend to both these owners is to have their veterinarians perform complete physical examinations on these horses to rule out any medical reasons for them to be thin.
Medical reasons for weight loss or failure to gain weight include:
- parasites
- dental disease
- gastric ulcers
- metabolic conditions such as Cushing’s Disease (PPID)
- chronic pain or infection, and many others
Once any medical conditions are ruled out or treated, these owners should look at their specific situations.
Feeding Strategies for Senior Horses
As horses age, they become less efficient in chewing, digesting and absorbing food. So we need to make this process easier for them, provide them with a higher quality and quantity of food, and perhaps provide them with additional nutrients.
Older horses that may have difficulty chewing may need to be transitioned from long-stem hay to chopped hay, hay cubes, hay pellets or a complete feed that contains both forage and concentrate. Hay cubes are usually soaked before feeding; some horses may need pellets soaked as well to make chewing easier. Concentrates may need to be in pelleted form, since whole corn, oats and other grains may be difficult for the older horse to chew.
Because older horses’ bodies are less efficient at digesting and absorbing food, they may need more and better food simply to maintain their weight. Try upping the amounts of both hay and concentrate by 10 to 15% and see if yours gains weight in two to three weeks. If your older horse is already eating all the hay and concentrate he can in two meals, add a third or even fourth meal.
Weight gain supplements for older horses
Supplementing with oil or fat is another excellent way to provide more calories to the older horse. Horses require more protein as they age (14 – 16% instead of 10 – 12%) but this protein must be of high quality or it will not be absorbed and used properly. Look for feed with a mixture of protein sources providing a wide range of the essential amino acids, especially the limiting amino acid lysine.
Older horses may need specific nutrients to help maintain weight and health. For example, horses naturally make Vitamin C and the B vitamins themselves. However, as their digestive systems age and become less efficient, they may make less of these nutrients, just when their bodies’ demands for them are increasing. Supplementing with prebiotics and probiotics is also a good choice, and yeast especially has been shown to enhance the digestibility of fiber and other nutrients.
If they seem to have lost their appetite, stimulate it with bee pollen, fenugreek, or banana (shown to be the number one preferred flavor of horses!).
Ask the Vet video on putting weight on a senior horse
In this video, Dr. Gray gives tips and tactics for an owner to try with their 28 year old horse that is a hard keeper.
SARAH: "I have an elderly horse who I love so much, and I was wondering how I can make life for him a bit more comfortable as he ages. He is a 28--" with a question mark-- "year-old Appendix Quarter Horse. He is retired. He gets turned out into an indoor arena every night with other horses. And he's in his stall from maybe 9:00 until 3:00. We often have young lesson kids work with him. No riding of course, but he gets hand-walked pretty much everyday-- just a few laps around the property. And we groom and bathe him often with the kids.
He is quite skinny and is a sad sight. We feed him twice as much hay as the other horses. And he gets grain once a day and an assortment of supplements, still can't seem to put weight on. Any tips on fattening him up and making his life a little better would help so much."
DR LYDIA GRAY: Life already sounds pretty good, but we'll try it.
SARAH: It's very wonderful, just very sweet.
DR LYDIA GRAY: "Assortment of supplements" was an interesting way of phrasing it.
SARAH: It's how I would describe my SmartPak. It's an assortment.
DR LYDIA GRAY: So when I look at a situation like this, the first thing I want to make sure they're doing is working with their vet. So get the complete physical exam. Make sure there's no underlying health condition. A horse this age-- what? 20s?
SARAH: 28 she thinks.
DR LYDIA GRAY: Could have Cushing's, could have a variety of things that they're unhealthy enough to make them a little bit run down or make them into that hard keeper. And so if you bring their health status up a notch, maybe they'll put on weight better or they'll extract the nutrition out of their food that they should be.
SARAH: Even things you might not expect like teeth problems.
DR LYDIA GRAY: Could be teeth, could be parasites. Could be simple things, could be hard things. But get the vet out.
SARAH: Yes.
DR LYDIA GRAY: When the vet is out have them show you, if you don't already know how, to do a body condition score and to assess the weight-- in some way measure the weight of your horse-- can be a tape. And then record those in a journal. So that now you have an objective measurement of your horse's health.
SARAH: Is this getting better? Is this getting worse, rather than just, "ooh, I wish he'd gain weight."
DR LYDIA GRAY: Right. Because we're going to give you some things to do. And if you're not following them-- I did A, and is he better or worse, then you don't know if you should continue that or try something else. And the thing I always tell people is try one thing at a time. Because if you--
SARAH: It's hard to resist.
DR LYDIA GRAY: I know it is because you want them to get better right now. But if you throw the kitchen sink at them and then the horse gets better, you're like, uh-oh. What was it? Now I have to do everything. Now you're taking out one thing at a time. So they said the horse gets hay in front of him all the time.
SARAH: It does. Yeah. Twice as much as-- well, they said twice as much as the other horses.
DR LYDIA GRAY: Oh.
SARAH: So that is a good point.
DR LYDIA GRAY: OK. So when I have a thin horse, I like to keep food in front of them all the time. I don't know if they have a situation where they can do that. But that would be ideal. And I would keep grass hay in front of this horse all the time if he has the teeth for it. And then I would begin to add some alfalfa hay in-- if he can tolerate it-- because it has more protein and it has more calories.
SARAH: While we're on the subject of the hay in front of them all the time, I just want to throw in some things here. Because my horse, Cody, is 29. And he is not underweight, but he's close. He's probably-- he's a four. He's not a four and a half where I'd like him to be on the body condition scale. And so with him, he's a hay waster.
DR LYDIA GRAY: Oh.
SARAH: So if we throw five flakes into his stall, he'll eat one, and then just pee on the rest.
DR LYDIA GRAY: Yep.
SARAH: And so what we do instead is we give him one flake at a time in a Small Hole Hay Net so that he's eating it, has access to it, and doesn't have the ability to just trash it all over the floor of the stall. And you get more out of what you give him.
DR LYDIA GRAY: The interesting thing with putting the hay in the hay net is you think it would slow them down. It does, but that phenomenon makes the thin horses gain weight and thick horses lose weight.
SARAH: Interesting
DR LYDIA GRAY: It brings everybody back to normal.
SARAH: I like that.
DR LYDIA GRAY: So that was a really good suggestion.
If his teeth aren't that great there's always the option of chopped hay, hay cubes, which probably you want to soak, hay pellets. So still getting that long-stem forage in there. He might be a horse that needs to transition to a complete feed, which is the hay and grain in the bag. And read the label on these, because you don't feed small amounts like three to five pounds of a regular fortified grain. You might need to feed 15, 18, 20 pounds of it, of course, spread out over the day.
Then you can add in other, I guess I would call them supplements, or other things to help hard keepers or senior horses add weight. My favorite, of course, is beet pulp. You knew I was going to say that. I like this because it is between the nutrition of hay and grain. And it's a fermentable fiber, which the horse's hindgut excels at. And they get energy from that and then calories. So a lot of horses that are underweight gain weight with the addition of beet pulp.
There's rice bran if you want to add fat, so moving to a new section. There's one way to add fat. You can just add straight fat too. And now it comes in a solid, so it's not as frustrating as oil. Because oil gets thick in the winter and hard to pour. And then it can go bad in the summer. It gets hot and it goes rancid. And it doesn't taste good. And it's not great.
SARAH: And depending what type of oil you pick, it can also have downsides.
DR LYDIA GRAY: Well, it can be very high in omega-- like corn oil is very high. The ratio of omega 3s to omega 6s, it's inverted. So that that's-- you're just adding inflammation to your horse and probably doesn't need that.
SARAH: Not something a senior needs for sure.
DR LYDIA GRAY: Definitely not. So I like the powdered fat. I think that's-- older horses become less efficient as they age. Digestive system is one of the organs that becomes less efficient. And so some digestive support like probiotics, prebiotics, yeast-- very good-- enzymes can help them, as I said earlier, extract the nutrition that you're already giving them, but they're just not getting.
And then I like that he gets turnout. You probably don't have grass which is why they don't put him on it, but, boy, pasture just adds bloom to horses. And if there's any way you can get him outside for turnout, that would be ideal. I can't tell from hearing this if he gets outside for some fresh air.
SARAH: He gets hand walked around the property they said.
DR LYDIA GRAY: Oh, OK. That's good.
SARAH: So that's a good opportunity for some grazing.
DR LYDIA GRAY: Oh, yeah. But everything-- reduce the stress in his life. Look at all aspects of the environment. The vet's great to walk around with you. Look at the food quality and quantity. Look at the grass. Look at the property. Look for stress. So is he having to fight off other horses for his fair share. Sometimes that gets overlooked. Does he have a buddy that he's friends with? Because as a horse, being isolated makes you nervous. So I think there's some--
SARAH: And people too.
DR LYDIA GRAY: Yeah, everybody. I think there are some things that need looked at that's not in this question. And then there's some opportunities to add some nutrition to this horse that can make him enjoy his golden years.
SARAH: That's right. All right. Well, I hope that some of those solutions work out for you. And that you guys have many more years ahead of you.
DR LYDIA GRAY: Yeah.
SARAH: He sounds like a wonderful horse.
Feeding Strategies for Athletic Horses to Gain Weight
Now for the young athletic horse in the question above. I don’t mean to put you on the spot, but since you mentioned some specific products, let’s review your current feeding program. You say you are feeding a “big amount” of grass/alfalfa mix. Since one person’s big amount may be different than another person’s, I recommend you weigh the hay you give your horse. You can easily do this by hanging it from a fish scale.
Horses should get about 2% of their body weight in total feedstuffs per day. So if all a horse is getting is hay and he weighs 1000 pounds, he should be getting 20 pounds of hay per day, preferably divided into two or more feedings. But because most horses receive concentrate for additional calories, vitamins and minerals, another combination might be 15 pounds of hay and 5 pounds of concentrate.
If you’re not feeding at least 2% of your horse’s body weight per day, then gradually work up to this amount. If you already are, then consider feeding 2.25% or even 2.5% of her body weight, if she’ll eat it. This may mean keeping hay in front of her all the time, or if that’s not possible, feeding three or four meals. Something to improve her appetite may also be necessary.
Selecting the right concentrate
Now let’s talk about your choice of concentrate, an equine senior feed. You may have been advised to put her on this because it’s highly digestible. However, if this is a COMPLETE feed, it’s a forage-based product with concentrate (calories, vitamins and minerals) added. That means it’s a dilute concentrate.
I suggest you go back to a true concentrate, one that isn’t made up primarily of forage, to “concentrate” calories for her. Otherwise, you’ll have to feed more of this product than she can possibly eat.
Finally, you said you give Fat Cat as a weight gain supplement. That’s a popular and successful choice for many people! But because horses are individuals, and what works for one may not always work for another, I suggest you try a different weight gain supplement. Fat Cat is a 25% protein supplement that is designed to supply amino acids for muscle building.
Perhaps your horse would gain weight better on a product that supplied fat instead. Fat is an excellent source of energy and calories and may work wonders on your horse! Another choice is prebiotics and probiotics and yeast. Some horses, no matter their age, simply need a little help in extracting all the nutrition possible out of the hay and concentrate they’re fed and live microorganisms like yeast and bacteria are designed to do this.
Ask the Vet video on tips to help a horse gain weight
Dr. Gray explains some additional strategies to try for helping encourage your horse to put on some weight.
I encourage both owners to read my article Managing the Hard Keeper, which has additional suggestions for thin horses, including sources of stress in their lives and the value of pasture!