Will Too Much Protein Cause Developmental Disorders in my Growing Horse?

Protein is a very important part of every horse’s diet.  Horses of all ages, developmental stages, activity levels, and reproductive status have essential amino acid requirements, amino acids being the building blocks of protein, and are what determine the quality of the protein.

Here’s an analogy:  consider amino acids as letters of the alphabet, and protein as words with structures such as muscle being the complete sentence.  Now put it all together; the combination of amino acids (letters) determines the quality or type of protein (word) that is formed.  The body is made up of many different types of proteins, all with distinct amino acid profiles.  If you have a shortage of or imbalance of the essential amino acids, the body cannot spell the words and complete the sentences, so the body can’t build and maintain quality tissues.

Consider this example:

  • 94% of a hoof is made up of amino acids (methionine for example)
  • The remaining 6% is comprised of fats, minerals and vitamins (biotin being just one of those vitamins)
  • Having protein or amino acid deficiency in the diet or feeding an unbalanced ration will compromise hoof integrity (brittle, soft, cracks, susceptibility to thrush, etc.).

cargill050aNow for the question above: Will protein cause developmental joint disease in my growing horse?

Growing horses have high nutrient requirements, with quality digestible protein (amino acids) being a very important and significant part of that nutrient requirement.

Confusion often occurs between providing nutrients and calories.  Providing a grain concentrate that is balanced for adult horses may provide too many calories (energy) and not enough of the nutrients (amino acids, minerals, fatty acids, vitamins ) the growing animal requires, for a couple reasons:

  1. Because unlike mature adult horses, youngsters cannot eat as much per meal (small stomach) and may never consume the recommended daily intake
  2. Because their hind-gut is immature (can’t digest/ferment forages very well) so they are unable to digest and absorb as many of the nutrients from forage as an adult horse does, leaving a nutrient gap in the total diet

The result is a mismatched calorie to nutrient ratio, with too many calories and not enough of the nutrients (amino acids, minerals, fatty acids, vitamins) that they need to grow and develop properly. High calories without the right amount and type of nutrients to support the rapidly growing animal can be problematic.  Resulting issues are often experienced as hay bellies, physitis, developmental joint disease (e.g. OCD), contracted tendons, etc.

Providing a diet balancer or a concentrate specifically designed to support growing horses is a great way to avoid the calorie to nutrient mismatch as well as provide digestible sources of those nutrients.  Diet balancers tend to be very dense in their protein, vitamins and mineral content, and very low in calories themselves.  This is why crude protein, for example, seems very high (e.g. CP 30%) in ration balancers and can cause concern among horse owners.  Fear not, feeding rates for these concentrated products are much lower than a traditional grain formula, providing all of the balanced nutrients needed in a volume that a small stomach can handle, without all of the extra energy.

Having too much poor quality protein in the diet will not be utilized by your horse, and may result in an amino acid deficiency, and makes for an ammonia filled barn due to excess nitrogen being excreted in the urine.  Having the right amount and combination of amino acids in the diet is key to supporting optimal growth and reducing metabolic waste.

Working with an equine nutritionist to find a horse feed that is specifically designed for growth and development and then following the manufacturer’s feeding directions should result in a practical and effective solution to ensure your youngster is getting the right balance of energy and nutrients, helping to avoid developmental issues and maximizing performance.

What are Essential Amino Acids in Protein, and Why Do They Matter?

Nutrition articles frequently refer to protein quality and essential amino acids. When we use the term crude protein, we are essentially talking about a calculation based on measured nitrogen. Protein is about 16% nitrogen by weight, so if we measure the amount of nitrogen and multiply it by 6.25, this gives us a measurement of crude protein. It does not tell us anything about the quality of the protein. If you tested pure nitrogen this way, it would be 625% protein!

Digestible protein is that amount of the protein that is actually digested by the animal. In an over simplified example, if you fed 100 grams of protein and measured 50 grams in the feces, the protein would be 50% digestible.

What is really important to simple stomached animals (horses included) is the content of essential amino acids in the protein. We commonly talk about 10 essential amino acids (EAA), the amino acids that must be in the diet as the animal cannot synthesize them. These are:

  • Phenylalanine
  • Valine
  • Threonine
  • Tryptophan
  • Isoleucine
  • Methionine
  • Histidine
  • Arginine
  • Leucine
  • Lysine

A common memory aid in many nutrition texts books is to use the first letters of these 10 as PVT TIM HALL. (All of you who had a non-ruminant nutrition course still remember this acronym!)

The other 12 amino acids can generally be synthesized in the body and do not need to be in the diet, although there must be a supply of appropriate substrate to produce them. Animal nutrition text books cover this topic in excellent detail.

Limiting Amino Acids

Limiting Amino Acids

When we talk about limiting amino acids, these are the essential amino acids most likely to be restricting the use of the total amount of amino acids present. In most species, lysine is the first limiting amino acid, with methionine and threonine close behind. We commonly talk about amino acids as the building blocks of protein. If you are once you run out of an essential amino acid, you cannot build any more animal protein and the rest of the amino acids are used inefficiently for energy.

If you have a horse on a diet that is calculated to have adequate “crude protein”, but essential amino acids are not present, the horse simply cannot use the protein to build and maintain muscle, hair, hoof and skin and you will see changes in the appearance of the horse, such as loss of muscle mass, rough hair, scaly hoof surface.

Feeding Oats to Horses – The Whole Picture

For decades, oats have been a staple in the feeding program of horses. Often considered a ‘safe’ grain option, there are pros and cons to this long-loved feed option. Upon closer examination, the nutrient profile of oats may surprise you. Read on and see the whole picture of oats.

Variability  - Oats are grown in many parts of the United States, Europe and Canada.  Depending on the genetic variety, growing conditions, soil type, management and harvest conditions, the nutrient content and quality of oats can vary widely.   Take for example the starch content which can range from 32% all the way up to 43%!  Variability of nutritional content can be high in oats.

Balance – Calcium and phosphorus work together to build strong bones and muscles, but they need to be in a balanced ratio to be absorbed and to work effectively.  For a horse, a ratio of 1:1 (calcium to phosphorus) is the minimum, but can range up to 6:1 and still be effective and healthy.  Generally speaking, oats have inverse calcium: phosphorus ratio and on average run 0.06% calcium to 0.45% phosphorus.

Starch level – The ‘low starch’ movement of the past decade has redefined what “low” is.  Low, being a relative term, historically may have meant anything below corn, which runs on average 65% starch.  So what is the starch level of oats?  The level of starch in oats can range from 32% up to 43%, however, the digestibility of the starch found in oats tends to be higher than in other cereal grains.  To put this into persecptive, take into consideration that ‘low’ starch feeds today run around 11-14%, and even oats are starting to look high!

Amino Acid Deficiancy – The building blocks of protein, amino acids such as lysine, methionine or threonine are required to effectively build and maintain muscle.  Though present in oats, the variability of levels is high and there are no guaranteed or consistent levels.

Digestibility – Processing oats by de-hulling, crimping, rolling, or crushing can provide a marginal increase in the digestibility of nutrients.  How much it increases, is actually minimal.  Consider this: next time you are cleaning out stalls, take a look at a pile of your horse’s manure.  See any oats in there?  Those have made it through the digestive tract without providing nutrition to your horse.

As you can see, oats are highly variable and nutritionally unbalanced in many areas important to horses.  Feeding your horse oats without balancing the diet could easily result in nutritional deficiencies.   If you feel strongly about feeding oats to your horse, it’s worth considering a commercial grain made with oats.

Alternatively, certain supplements are made to compliment oats and fill the nutrient  gaps for your horse.  This way, you can feel good about feeding your horse oats, and your horse will feel good with balanced nutrition.

Can You Feed the Flies Away From Your Horse?

In warm months, it seems like flies and other biting insects are always the #1 enemy of horses. They annoy, they bite, they cause itching, bumps, swelling and skin reactions. Often times horse owners go to great lengths to lessen the impact of flies on their horses. But can what you feed your horse actually have an impact on your fly population?

There are fly preventatives that may work for some horse owners which involve feeding a certain ingredient to the horse. Many people claim that giving apple cider vinegar daily will keep the flies away, while others swear by garlic powder or brewer’s yeast. The fact more often than not is that it is very difficult to get the horse to eat enough of these items to make a difference where flies are concerned because they typically have a strong taste and smell; the trick is getting the horse to ingest them at all. The important thing to remember is that horses are all unique and what works for your neighbor’s horse may not have the same effect on your horse.

Another alternative to feed the flies away is using a feed through IGR additive that is labeled for horses. This active ingredient does not get absorbed by the gut, but instead passes through into the manure, hence the ”feed through” name. Once in the manure, the Insect Growth Regulator (IGR) causes the fly pupae to not mature into adult flies. With disciplined feeding, these products can be effective but may be expensive. One warning with this type of fly control – if you have close neighbors who aren’t controlling their fly populations you will likely see little difference because their flies will continue to come snack on your horse.

More traditional methods of fly control should not be discounted, including finding an effective fly spray, using fly sheets, and changing turn out times to when flies are less active. Cleanliness in your stable and proper manure management can also have an impact on fly populations.

In Defense of Starch

Like a celebrity on a downward spiral, starch has been getting a lot of press in the last few years…and most of it negative.  Unlike celebrities, starch doesn’t gain anything from the media exposure.  Although it may be unpopular, I’d like to take a moment to say a few words in defense of starch; a (recently) under appreciated, yet useful nutrient in horse diets.

But first, let’s start with what it is.  Starch is a complex chain of sugar molecules, which is the main source of energy for plants.  It is stored within the cell walls of the plant and therefore, considered a nonstructural carbohydrate (NSC).  Starch in horse feeds are most commonly sourced through grains such as oats, barley, corn, rice or wheat and the co-products of these grains such as corn distillers grains, rice bran or wheat midds. 

Glycemic response of oats and controlled starch diets, in horses

When ingested, starch molecules are broken down into smaller sugar molecules (glucose) that are readily absorbed. With the help of insulin, the glucose in the bloodstream is ‘picked up’ by muscles and other tissues to either be used to support activity or stored (as glycogen) for future energy needs.  Hard working and active horses need glucose and glycogen to support their activity levels and recovery from activity.   It’s also worth pointing out that NSC’s are a very efficient pathway to providing energy to the horse and to aid in muscle recovery (glycogen repletion), particularly in horses performing athletic activities.

Most horse owners know that too much starch at one time can overwhelm the horse’s digestive system.  That excess, undigested starch could leak into the hind gut where it can rapidly ferment, leading to an overproduction of gas and lactic acid, which in turn, could cause gas colic and/or acidosis which could then lead to laminitis or other issues.

You’re probably wondering, if it’s needed by horses for energy, but also potentially dangerous then how does the horse get what he needs without wreaking havoc?  The answer lies in the QUANTITY of starch consumed in each meal.

The majority* horses can tolerate a moderate level of starch each day.   This is not to say, all at one time.  There is a big difference!  Consider the digestive system of a horse to be like a waterway – it can tolerate a certain quantity of water running through it (or in this example starch) but if there is too much at one time, the water overflows and goes where it is not supposed to go.  Same with starch in the digestive system – the body can handle a moderate quantity of starch released at a controlled rate, but too much at one time (or from too big of a meal) and the whole system gets out of whack. 

I offer up one last nugget to consider: oats – the long-time staple of ‘safe’ feedstuffs for horses, actually contains approximately 40% starch. Now there’s something to think about…

So, in defense of starch, I’d just like plead the following.  When consumed in moderate amounts/meals,  frequently over time, starch is a useful and practical source of energy for most horses. 

In my next post, we’ll talk about how to evaluate starch levels in feeds.  Stay tuned for more….

*Horses diagnosed with a form of Equine Metabolic Disease (EMS) require a diet that is closely managed to control and limit the amount of NSC (including fructan from forage) in their diet. 

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.