My Horse is Skinny. What Should I Do?

By Fernanda Camargo, DVM, PhD; Laurie Lawrence, PhD; and Bob Coleman, MS, PhD, PAS, of the University of Kentucky Department of Animal and Food Sciences

As we understand more about the impact that obesity and emaciation have on animal health, it is imperative that we strive to keep our horses at an optimum body condition. We’ve learned how to body condition score (BCS) our horses, so let’s take a look at what horses with a BCS of 4 or lower might look like:

Here are some tips on how to help your horse gain weight.

Think about calories first.

A mature horse will gain weight and condition when the number of calories it consumes is greater than the number of calories it uses. Therefore, to increase body condition the horse must either increase calorie intake or decrease calorie use (or both). Calories are important to muscle gain as well as fat gain, so the diet’s calorie value is important.

Understand where calories come from.

Horses consume calories from their pasture, hay, and grains and concentrated feed (such as a sweet feed). However, most people underestimate the importance of hay and pasture in the horse’s diet. If hay and pasture are good quality and abundant, they can contribute a significant portion of the calories that a horse needs. The fiber in hay and pasture is also important to keep the digestive tract healthy. If a horse receives too little fiber in its diet it might be less able to digest its other feeds efficiently. As such, ensure your thin horse has ample hay or pasture access.

Feed good-quality hay.

Choose hay that was harvested at early maturity for horses that need to gain weight and body condition. Early maturity hay has more leaves, softer stems and very few seed heads. Early maturity hay is high in nutrients and it is palatable so horses will eat more of it. At this early stage of harvesting, legume (alfalfa, clover), grass (orchardgrass, timothy, bluegrass, etc.) or legume-grass mix hays are desirable for horses that need to gain weight. When you are comparing more mature hays, then mature legume hays will provide more calories than mature grass hays. If mature hay is used then it will be more difficult to get a horse to gain weight as it is less digestible and less palatable.

Feed enough hay.

Most horses will eat about two pounds of hay for each 100 pounds of body weight. So, a 1,000-pound Arabian will eat about 20 pounds of hay a day while a 1,250-pound Thoroughbred will eat about 25 pounds of hay a day. These are just average numbers and some horses will eat more or less. Also, some waste is always expected so if the horse will eat 20 pounds per day, you will probably have to feed 22-24 pounds per day. If a horse has lost weight because it has been on restricted feed intake the amount of hay offered should be increased gradually.

For example, if a horse has been in a poor pasture or in a group feeding situation where other horses ate all the food first, its digestive tract will need time to adjust to a higher level of feeding. If you are offering hay and the horse is not eating it very well, make sure to have his teeth examined. If the dental exam is normal then consider trying a different kind of hay; the goal is to find something that the horse likes so it will eat more hay.

Make use of available pasture.

Horses that have become thin during periods of training or even illness often benefit from turn-out into a high-quality pasture. During the growing season a well-managed pasture can provide many nutrients and because grass is very palatable, it is good way to increase calorie intake. However, horses should always be adapted to pasture slowly to minimize the risk of digestive upset.

Pasture can be an excellent source of calories, but only if there is enough nutritious and edible plant material in the paddock. Just because a pasture has green material in it doesn’t mean it has adequate nutrition. If horses kept on pasture are thin it suggests that the pasture is not providing adequate nutrition and supplementation is needed. The first feed that should be offered as a pasture supplement is hay. If hay is put in the pasture and the horses eat it readily it probably means that the pasture quality is low.

Consider supplementing with a concentrate.

After adjusting the hay and pasture offered to a thin horse, the concentrate portion of the diet should be evaluated. Concentrates (sweet feeds, pelleted feeds, or plain cereal grain like oats or corn) are used to provide a concentrated form of calories. One of the advantages of a concentrate is that it provides more calories than the same amount of hay. So if you gradually replace five pounds of hay with five pounds of a concentrate feed in the daily diet you can increase total calorie intake.

There are many good quality commercially available concentrates available. A commercially manufactured feed usually is more desirable because it is also fortified with other nutrients. Always purchase feeds that are formulated specifically for horses. Feeds formulated for other livestock could contain additives that are toxic to horses.

Feed an appropriate amount of concentrate.

It is tempting to feed large amounts of concentrate to thin horses to get fast weight gain. However, large amounts of concentrate increase the risk of colic. So, it is generally safer to feed more high-quality forage and less concentrate to achieve the same effect. If a horse has not been getting any concentrate, the first meals should be very small and then increased gradually.

Large meals have a greater risk of digestive upset so if a horse is getting more than five pounds of concentrate per day, it should be divided into two meals. If it is getting more than 10 pounds of concentrate per day, it should be divided into three meals per day. Many feed companies sell concentrates with added fat.

Feed fat.

Fat is a good source of calories so fat supplemented feeds are useful for adding condition to a thin horse. Alternatively, fat can be top-dressed on a regular concentrate. The most common way to do this is to add vegetable oil to each concentrate meal. The amount of vegetable oil should be small at the beginning, to allow the horse to accept it; later the amount can be increased to three to four ounces per feeding.

Feeding management.

Feeding the right feeds in the right amounts is important, but so is feeding management. Horses can become very aggressive during meal times, and invariably, lower horses in the pecking order will be chased out of their buckets and hay piles. In many cases the thin horse is the one at the bottom of the pecking order and the fat horses are the ones at the top of the pecking order. In group feeding situations, make sure feeders are spread out enough to allow all horses to eat at once.

The best management practice is to feed thin horses separately to make sure that they get the amount of food they need. Horses can be fed in stalls or, alternatively, concentrate can be given individually using nose bags if horses are together in a paddock. If this is not possible, then consider regrouping horses to put individuals with similar requirements together. For example, an older thin mare might do better if she is kept with weanling fillies than with younger, fatter mares, because she will need the same quality of hay and amount of concentrate as the fillies.

Reduce calorie expenditure.

A horse will gain weight if calorie intake is greater than calorie use. Therefore, decreasing calorie use might be necessary for a horse to gain weight. Horses burn calories in a number of ways, including during exercise, staying warm in the winter, running away from dominant horses, and fighting fight flies in the summer, among other ways. If you are having difficulty keeping your horse at an optimum body condition score (BCS), consider decreasing exercise levels until the horse has reached an adequate BCS.

If the weather is cold, provide as much shelter as possible. Heat loss is increased by wind and wet so if the horse can remain dry and out of the wind, if will reduce the calories needed to stay warm. A blanket might also reduce heat loss, but make sure that the blanket is waterproof, or your horse will be worse off carrying around a wet, cold, and heavy blanket.

In hot weather a cool, well-ventilated area will also help minimize calorie use. Protection from biting insects will also reduce the horse’s activity. Any other management changes that will encourage a horse to spend more time eating and resting than moving about will help to reduce calorie use and increase calorie intake.

Change paddocks if the horse is lowest in the pecking order.

Most horses will learn to live in peace with each other if they have enough space. However, some horses, especially the ones who were raised alone, will not have learned herd dynamics, and will put themselves in jeopardy all the time. These horses don’t understand horse body language, and therefore, will not get the cue and leave more dominant horses alone. The dominant horses will keep chasing these horses, who, in turn, will waste a lot of calories running around.

Generally, dominant horses will be fine if left alone, especially if there is enough space. However, there are cases where dominant horses bully younger horses or horses that are low in the pecking order. Regardless of what your case is, you will need to separate a horse that is constantly being picked at by other horses. These horses live under constant stress and will never have a chance to put on weight. Moreover, it is not a safe situation for either you or your horse. There are countless cases where horses were run through fences, or handlers that were caught in the middle of a horse fight.

Reprinted with permission from the University of Kentucky.