FATS, FATS, AND MORE FATS

We all think that we know the role of fat in a horse’s diet. It helps him gain weight, right? Like the other nutrients, there is so much more to it. In this month’s article we’ll talk about what fat does, why the type of fat matters, and the practical everyday use. After all, your horse’s concern is what is in his feed bucket, not what is written on this page.

We’ll start with some terms and descriptions. Technically, fats belong to a molecular class known as lipids. For our purposes here, we’ll use the term “fats” as we talk about fats and oils. Fat is solid at room temperature; oil is in a liquid form. Fats come from many sources, both plant and animal. You won’t see animal fats used in horse feeds though, so we don’t have to talk about the concerns of saturated fats.

Before we wade in too far, you should know that studies of fats and horses are ongoing and there is still much to learn. If you research articles from twenty years ago, you will find that they have different information than articles written ten years ago, and those are different than the articles written today. We are still discovering the ways in which different fat sources affect the horse, which fats are healthier, which fats should be avoided. We don’t even have an accurate measure of how much fat should be present in the horse’s diet (but there are lots of suggestions out there.) Why is this? One would think that by now we would have explored and tested every aspect of this.

Part of the reason, I believe, is because the horse’s natural diet does not contain a lot of fat. The most natural diet for a horse is forage first. We add things like ration balancers, commercial feeds, and supplements because with the increased demands that we make on him, it can be hard for the horse to get enough calories, protein, vitamins, minerals, and other nutrients from his forage. Somewhere in the history of our collaboration with equines, we realized that they tolerate fat in their diet, and tolerate it very well. We are essentially adding something to his diet that he would not access easily in the wild. Being humans, we want to study it, test theories, and see where it leads. Research is driven by current needs, current trends, and the improvement in equipment and measuring ability. We’ve seen this happen in the past with research into diets for older horses. Now that horses live longer, more research is done on them, which helps them live longer still.

So why are we feeding more fats to horses, when it isn’t a huge part of their natural diet? It turns out that adding fat has a lot of benefits. First, it contains two to three times more calories per gram or ounce than carbohydrates and protein. Adding fat is safer way to increase your horse’s calorie intake because you can get more calories into him without giving him as many pounds of feed. (As a reminder, horses should not have more than five pounds of a concentrated or commercial feed per meal as it can overwhelm their digestive tract. This does NOT apply to forage though, which they eat at a slower rate.) Adding calories by feeding a large amount of carbohydrates, such as corn or oats, can overload the horse’s GI tract when it breaks down the starches and sugars, and the starch especially can lead to laminitis and colic.

Calories equal energy, and the energy that is produced by the breakdown of fats appears to be “cooler” than that of carbs. What that means is that a horse on a high-fat diet may be more levelheaded than he would be on a high-carb diet. There is still more research to be done in that area, but it has to do with the way that the sugars and starches in carbs break down versus the way the fat molecules break down. If you have a horse with metabolic issues that requires a low-carb diet, then feeding fats is a way to help him maintain his condition and health. The break-down of fats is slower than that of carbs, which helps lead to a longer, sustained energy release instead of the shorter burst associated with carbs. Partly because of this, the use of fat in a horse’s diet helps to increase his endurance.

Fats are also easier to digest, without the added burden of producing the amount of heat that is associated with the breakdown of carbs. Let’s digress for a moment and explore a popular myth. I’m sure you’ve heard it…some old timer has told you that adding corn to your horse’s diet in winter will help keep him warm. Nope. What it will do is give him a big jolt of carbs that break down into an abundance of starches and sugars. As we read above, too much starch can overload the horse’s ability to digest it and lead to laminitis or colic. If you want to keep your horse warm in the winter, give him more hay. The fiber in hay is a carbohydrate too, but it is one that is harder to break down. The work that the body does to break down the fiber generates metabolic warmth: it warms him from the inside.

Okay, back on track. So, what else does fat do? In addition to improving a horse’s endurance, there is evidence that fat also helps your horse in tolerating heat (the kind that we associate with weather.) More research needs to be done, but it’s thought to go along with the fact that the breakdown of fat molecules doesn’t generate the amount of metabolic heat that carbs do.

Yes, fat can make your horse overweight if he eats more calories than he uses on a regular basis. Just like us, horses are very efficient at storing extra calories. Being overweight isn’t good for him and can stress his cardiovascular system, lead to mechanical laminitis, and increase the chance of metabolic issues. If you are unsure of your horse’s weight, ask your veterinarian for guidance. Decreasing the amount of fat that your chonk eats is one way to help him lose weight. He still needs it in his diet though. Fat helps the body use vitamins A, D, E, and K. Those are fat-soluble vitamins, meaning that they break down in lipids and are transported through the body and stored with fat cells. (We’ll talk more about the role of these vitamins at another time.) Fats also provide the essential omega-3 and omega-6 fatty acids that the body can’t produce on its own.

Fats break down into fatty acids and glycerol. As these components travel through the body, they act on hormones responsible for growth and maintenance. They are important for brain development, and they interact with protein to keep the body structurally strong. They also aid in the development of healthy skin and hair, and they help to transport certain vitamins through the body. Like the other nutrients, they don’t act alone but instead play a part in a complicated dietary system. True fats don’t contain any other nutrients. There are no proteins, carbs, vitamins, or minerals in true fats. If you decide that adding fat would be beneficial to your horse’s diet, make sure that you are still providing him with the other nutrients. We’ll look at vitamins and minerals in the future, as all are important parts of his health.

Hopefully I’ve convinced you now that there is a place for fat in your horse’s diet and you’re wondering what the source of fat should be. Thanks to increased research in the last decade, we know now that the type of fat matters. Since we don’t feed animal fats to horses, that leaves plants as a source. Let’s remove another misconception here: mineral oil should not be part of a horse’s diet. It’s used in colic cases because it is NOT absorbed by the horse’s body: it is strictly a lubricant. It’s not even a food product, as it’s made from petroleum.

The fats that we feed to horses most commonly are oils that are produced from corn, soybean, and flax. Less frequently used oils are sunflower, canola, coconut, palm, and camelina. Oils are produced from the seed by either squeezing or by chemical extraction using a solvent. Forages contain small amounts of oil too, but they tend to be less digestible than the seed oils. Fats can also be solid ingredients, such as rice bran and ground flax. While still high in calories, they don’t have as high of a fat content as the oils.

While fats all have a similar energy value (that is, similar calorie count), they differ in their chemical make-up because they contain different fatty acids. As I said before, there is still a lot of on-going research, and currently omega-3 and omega-6 fatty acids are in the news, with omega-9 entering the conversation too. We’re starting to realize that the proportion of omega-3 to omega-6 fatty acids matters, not just the amount.

Let’s move on to what concerns your horse: that is, what ends up in his bucket. If you need to add more calories to his diet and you decide that fat is a safe way to do it, you have lots of options. There are high-fat feeds on the market. I consider high fat as anything above 10% (remember, that means it is 10% of the ingredients in the bag, not 10% of his diet.) There are also high-fat supplements in both solid and liquid form. You can use these to top dress his regular feed. Solid high fat supplements typically contain 20% or more fat, and oils are 98-99%. Of course, these differ by manufacturer, so take a moment to look at the bag tags or labels and determine the fat content for yourself. Be careful that you don’t confuse high-fat supplements with high-fat feeds as they are fed in different amounts. While they are usually fortified with other ingredients, fat supplements are not great sources of vitamins and minerals and are not at all like ration balancers. If you are unsure, ask your feed store for guidance.

Different qualities of feed will have different fat sources. Fat sources in the fixed nutrition/expensive feeds tend to be oils such as soybean and flax, and solids such as rice bran, ground flax, and soybean. These are considered high quality fat sources. You will likely see them in the fixed-formula/mid-range feeds too. Least cost ingredient/low-cost feeds will contain corn and vegetable oil. While they add calories, they aren’t the best choices for achieving the proper omega balances. As we discussed a few months ago when we looked at the different tiers of feed, you get what you pay for. Better quality ingredients will increase the price of the feed.

Fats are usually listed right after the protein information on the guaranteed analysis but be careful: some feed companies list fat after fiber. Make sure you read your bag carefully. The number will be expressed as a percentage. For example, if you are feeding a 10% fat product, then 10% of the 50-pound bag, or five pounds, contains fat. Let’s say that you feed five pounds per day of this feed. Then your horse is getting a half-pound per day of fat from this feed. (0.10 x 5 = 0.5)

How much fat does a horse need? That’s a tricky question. If you have a horse that is a hard keeper, he could probably have more fat. If he is an easy keeper and is overweight, then cutting the amount of fat that he eats can aid in weight loss. You should consult your veterinarian if you have any questions or concerns and ask your local feed store for guidance too.

How much fat can a horse tolerate in his diet? I wish I could tell you! That is a subject that current research is trying to determine. Some studies indicate that it could be as much as 20% of the horse’s diet. Again, talk with your veterinarian before feeding that much.

As you introduce fat to your horse’s diet, do it slowly. If you are switching from one commercial feed to another, take at least two weeks. A longer period is recommended if you are changing the feed of older horses. If you decide to start top dressing with oil, a period of three-four weeks is recommended. This is so the flora in his gastrointestinal tract have time to adjust. You may notice a change in his manure. Check with your veterinarian if you have concerns and remember to tell the vet of the changes in feed.

As is the case with the other nutrients, there is more to the use of fat than we realize. It has a place in your horse’s diet, and it impacts his overall health. The key is to understand its use and then to keep current with research by consulting with your veterinarian and feed store.