Adding Oil to a Horse’s Diet

Healthy, inside and out

Adding vegetable oil to equine feeds or to equine diets has been a standard practice for literally hundreds of years.  Old horse traders knew that adding oil could help slick up a horse for sale long before the science of measuring digestible energy was developed.

There are multiple ways that vegetable oils are added to horse diets.  A common practice among horse owners is to add various quantities of oil on top of an existing diet.  A cup of oil will weigh about 8 ounces and contain about 2,045 Kcal (Calories).  A 500 kg (1100 lb) horse at light work requires about 20 Mcal or 20,000 Kcal, so that oil would provide about 10% of the required DE per day.  For comparison, a pound of oats, as fed, provides about 1,320 Kcal, so adding oil provides a lot of Calories in a small package.

A key element to consider in adding oil on top of an existing diet is that oil adds only Calories (crude/unrefined oils may also contain some Vitamin E), so it is possible to alter the nutrient to Calorie ratios in a diet.  With the addition of moderate quantities of oil, this is unlikely to create issues.  If a substantial amount of oil is added on top of an existing diet, the diet may no longer be meeting the horse’s requirements for other nutrients.  Corn oil, soy oil and other vegetable oils may be used for top dressing diets.

Feed companies also add oil to formulated feeds and will declare the minimum amount of crude fat on the tag.  This is primarily from the oil in the grain and the added oil if above 3-3.5%.  A feed that is tagged at 7%  will generally contain about 3-4% added oil.  Internal formulations systems will also calculate the total DE of the feed, which includes energy from fat as well as from NDF (neutral detergent fiber), NFC (non-fiber carbohydrates) and protein.   This allows the company to maintain the balance of energy sources as well as appropriate nutrient to Calorie ratios.

If a product refers to Omega 3 or Omega 6 fatty acids, the actual quantity or % of each fatty acid may also be declared on the tag or on the bag.  The ingredient listing will generally identify the oil or oils that may be included in the product. 

Top dressing with oil is a common practice, which can be done successfully, when done in moderation with a careful eye on meeting the total nutrient requirements of the horse as well as the energy requirements.  Adding too much may result in other nutrient issues.

Are All Oils the Same for Feeding to Horses?

Adding oil or fat to horse diets was a common practice long before research determined the many benefits of added oil diets.  Horse traders hundreds of years ago knew that if they wanted a horse to gain weight and develop a slick hair coat, adding oil to the diet was one way to do it.

Are all oils the same? 

Like many questions in the equine world, the answer is yes and no. The common vegetable oils used in horse feeds are corn oil, soy oil and flax oil (linseed oil).  Canola oil, sunflower oil, coconut oil and palm oil are also used, but less frequently.  Animal fats, excluding fish oil, are not currently used very commonly in horse feeds in the United States due to customer concern, and potential palatability concerns.

What is the difference between fat and oil?   

There are multiple chapters in nutrition books written about fats and oils.  Animal Feeding & Nutrition, Tenth Addition, by Jurgens and Bregendahl is a standard text.  For simple practical purposes, a fat is solid at room temperature and oil is liquid due to the differences in composition.  For those of you who like the full science, fats and oils are:

  • Also referred to as lipids or ether extracts
  • Insoluble in water and soluble in organic solvents
  • Contain about 77% carbon, 12% hydrogen and 11% oxygen. 
  • They all contain about the same energy, 9.45 Mcal/kg or 4,290 Kcal/lb. 
    • This is about 2.25 times the energy content of carbohydrates.

What’s all the talk about Omega Fatty Acids?

There may be substantial differences in the Omega 3 and Omega 6 fatty acid profiles of different oils, particularly in the content of the essential fatty acids (EFAs) linoleic acid (C18:2 n-6),  linolenic acid (C18:3 n-3) and arachidonic acid(C20:4 n-6)  Arachidonic acid can be synthesized from linoleic acid and is essential if linoleic acid is not present.

  • Corn oil will be higher in linoleic acid, an n-6 or Omega 6 fatty acid. 
  • Soy oil, particularly mechanically extracted, will contain more linolenic acid, an n-3 or Omega 3 fatty acid, than corn oil. 
  • Linseed oil, from flax, contains the highest % of linolenic fatty acid. 
  • Fish oil from certain cold water sources is the highest in Omega 3 fatty acids, although it may present some palatability issues.

How are they made?

Vegetable oils come from the seed of the plant with most being in the germ.  They are produced by either solvent extraction or mechanical (squeezing or crushing the seeds) extraction.  They can either be refined or in crude form, depending on the processing. All of the vegetable oils contain essentially the same amount of energy and are generally palatable if processed and stored properly.

Fiber Ingredients in Horse Feed

Imagine that perfect summer day. Your horse is out grazing on his pasture and taking in nutrition through the leafy green grass. You are confident that he is eating a high quality, consistent fiber source that is providing an excellent foundation for his diet. By using the high quality, consistent source of fiber that you value in your hay and pasture and putting it in your feed bag we are able to give your horse the benefits of his summer pasture all year long and in any situation.

Because fiber is such a huge part of your horse’s healthy diet (he should be eating no less than 1% of his bodyweight daily in hay or pasture) it is essential that it is present in nearly everything he consumes. With manufactured feed we are able to control the amount of fiber in the ration by using some specific ingredients.  Using alfalfa/legume products can  help to add protein, energy and calcium to the feed, while grass products can help add protein and fiber. Some of the most common sources of fiber in horse feeds are:Forage Products give the benefits of hay or pasture

  • Alfalfa Meal
  • Dehydrated Alfalfa
  • Suncured alfalfa
  • Coastal Bermuda Grass
  • Ground Grass
  • Ground Soybean Hay

It is important to always remember to read your feeding recommendations – just because a feed utilizes one or more of these forage products and has a high fiber content that does not mean that it can be fed as a sole ration.

Grains in Horse Feeds

Grain is one of the most traditional meals fed to horses. For years people have fed oats to race horses, corn and barley to plow horses, and the good old “cob” (Corn-Oats-Barley mix) as a treat or as a staple of the diet.  With the research and studies that have been done in the past decade, we have discovered that feeding straight grain, especially in large amounts and without vitamin or mineral supplementation, is not a healthy choice for your horse. That said, grains are still very good ingredients in a horse feed when used to provide valuable sources of energy and fiber, but need to be combined with other products and adjusted to meet requirements for protein, vitamins and minerals, so that a balanced diet can be achieved.

When grains are used in horse feeds they are most commonly processed to help enhance digestion. Processing methods can include cracking, screen cracking, flaking, kibble, toasting or heat processing . The grains that  can be fed to horses include triticale, wheat, rye, rice and grain sorghum although these are much less common than “The Big Three” grains that are most typically used in horse diets:

  • Corn is added to feed as an energy source and provides a whopping 1.54 Mcal of digestible energy (DE) per pound. However, corn is also one of the grains that is highest in content of starch. Whole corn is not typically used in textured horse feeds unless it is processed (flaked , cracked, etc.), and fine ground corn should not be used in textured feed because it increases the risk of colic. While it has received a bit of a bad rap in recent years due to its higher starch content, it can be, and is, still a valuable piece of the formulation of a total feed, as long as the proper attention is given to the overall starch level of the finished feed.
  • Oats is one of the more common grains used under the heading of Grain Products

    Oats are probably the most traditional grain fed to horses. Oats provide a source of fiber but energy content is considered low for a cereal grain, and they have a moderate amount of starch when compared to other straight grain rations. Whole oats consist of clean, cultivated oat grains. Crimped oats have the hull of the oat broken while rolled oats have been steamed and rolled flat.

  • Barley is also an energy source, and has a fiber and starch content somewhere in between oats and corn. Whole barley consists of whole kernels of barley with the outer covering intact. Barley has a tougher hull than oats, so it is most commonly processed (crimped, rolled or steam flaked) when put into horse feeds. Whole barley is used in some instances, but is not ideal.

 

Roughage Ingredients in Horse Feed

If you were to take your horse’s digestive tract and stretch it out, it would measure nearly 100 feet from end to end. That is a long trip for the nutrients in feed to make! We feed roughage to our horses to provide a source of bulk and fiber to the diet, and this roughage helps to carry nutrients through that long digestive tract. Roughage consists primarily of bulky, coarse plant parts with high fiber contents. Most sources of roughage are things like hulls, husks or pulp – this type of ingredient provides the fiber and bulk needed for proper digestion, and keeps the horse’s gut functioning as it should. Roughage sources can include things like rice hulls, dried citrus meal, rye mill run, etc., but some of the most common forms of roughage are listed and explained below:

  • Beet Pulp: this is a by-product of the sugar beet industry. It is the dried residue that has been extracted in the process of manufacturing sugar from sugar beets. Beet pulp has long been fed as a way to put weight on horses.
    • It is high in digestible fiber and digestible energy and is low in starch, which makes it fairly safe to feed.
    • Beet pulp pellets are usually soaked when fed; this can also help increase water intake.
    • However, beet pulp by itself is not a balanced product. It can fit very well into a feeding program, either as a supplement or as an ingredient in a commercial feed, but if fed by itself the horse will be missing essential minerals, amino acids and protein.
  • Soy Hulls: these are the outer covering of the soybean. These hulls are removed before soybeans are crushed for oil, and are an excellent ingredient that is mainly used in pelleted feeds.
    • They provide a good source of energy and are an easily digested fiber source.
  • Oat Hulls: these are the outer covering of the oat kernel.
    • They are high in fiber, low in energy, and low in protein.
    • Because of their high fiber content they make a good source of roughage.

These are a few of the most common sources of roughage. Depending on where you live, there may be other more prevelant sources of roughage available. No matter what the specific ingredient is, the main function of roughage in the diet is to provide bulky fiber that helps pull the contents of the digestive tract along and assist in keeping the gut functioning.

Grain By-Products in Horse Feeds

To many people, by-products have a negative connotation. Most think of by-products as “left overs”, “junk” or “fillers”.  This is simply not true. Some of the most nutrient rich ingredients we have for horse feeds are made of the product that remains after a grain has been processed for another specific purpose. These ingredients can include things like brewer’s grain, corn gluten feed, oat groats, etc. Some of the most common members of this category that we see used in our horse feeds or even fed as a sole ingredient today are:

Wheat Midds are obtained from the milling of wheat, wheat bran, wheat shorts, wheat germ, wheat flour, etc.  Midds are a good source of energy, protein and fiber for horses. Additionally, wheat midds help create a nice pellet that holds together well; midds can enhance the pellet quality and make a clean pellet with minimal dust and fines.  

Rice bran is a by-product of the rice milling process. Rice bran is found between the outer hull and inner grain of rice and is used as a plant-based fat source (typical rice bran products contain 20% fat or more). Rice bran can be fed in a powder form, extruded into a nugget, or added to commercial rations and pelleted to increase overall fat content of the feed. Rice bran works well as an ingredient but must be balanced to make up for a high phosphorous and low calcium content. It also must be stabilized or it will turn rancid very quickly due to the high oil content.

Wheat Bran is a by-product of the flour industry. It is rich in dietary fiber and essential fatty acids; bran mash has been historically fed to horses both as a treat and for a laxative effect that was thought to prevent colic.  We now know that too much wheat bran can cause problems such as enteroliths, and that laxative effect is actually a result of too much wheat bran irritating the gut lining of the horse. Similar to rice bran, wheat bran intakes must be managed to account for a very high phosphorous content.

These are just a few examples of some common grain by-products that are used in horse feed and can help create a healthy and nutritious diet. While not a “grain” by-product, even the ever-popular beet pulp is a by-product – it’s what’s left after sugar beets are processed! Before you dismiss a feed because it lists by-product as an ingredient, remember that these items, when balanced properly as a part of the overall formulation of the diet, can be an excellent source of many different nutrients.

Protein Ingredients in Horse Feed

Protein (and more specifically the amino acids that make up protein) is essential to a balanced diet. It is probably one of the most referenced nutrients in horse feed, and most horse owners will know the protein content of their feed. But how do we get the protein into the feed? Sources of protein for humans may come from a juicy steak, a nice salmon filet, or a tender pork chop. We derive most of our protein from meat sources which makes sense for us since we are carnivores. The horse, on the other hand, is an herbivore; many of the types of protein that we consume as humans do not come into play in our horse’s diet. However, we do know that the horse has a nutritional requirement for protein and so when we formulate feeds we can use certain plants that are high in this particular nutrient. Some of the most popular ingredients used to add protein to horse feed are:

Soybean Meal – This is the most common form of plant protein. Soybeans are readily available throughout the country and have the highest concentration of protein of any of our plant sources, with a typical level of 44-48%. Additionally, soybean meal contains a close match nutritionally to what horses require for amino acids. Especially important in this profile is the amino acid lysine, which is essential in young growing horses.

Canola Meal – Canola meal is the closest to meeting the nutritional profile of soybean meal and has a protein content of 35-44%. Canola meal is a by-product of oil removal from

canola and has slightly less lysine content than soybean meal, but still enough to meet the requirements of horses.

Linseed Meal – this is also a by-product and is derived from the processing of flaxseed. Linseed used to be commonly fed to show horses to add shine and bloom but its popularity has waned as ingredients like rice bran and vegetable oil have taken its place. Linseed meal has a typical protein level of 33 – 35% but it has significantly less lysine than either soybean or canola meal.

As you can see, we have several options to help us meet the requirements that our horses have for protein. By adding one or more of those options to our formulas we are able to provide a diet that is balanced, healthy, and nutritious!