Confused by Carbs in Horse Feed?

There are lots of terms, and even more opinions, when it comes to carbohydrates in horse feed. Here, we break it down to the basics so you can have a foundation to understand what’s important to your horse!

understanding starch and sugar levels in horse feed

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Do You Know the Feeding Rate For Your Horse Feed?

scooping feedI was visiting with some friends at a recent horse owners meeting. I saw a trainer I had visited several times in the past few years, answering nutrition questions and making recommendations. I asked how his horses were doing and if he had made any changes to his feed program. He replied that he had switched to a competitor’s product a few months ago and the results were terrible. His horses had lost weight, their coats were dull and he went back to feeding his old mill mix.

I asked which product he was feeding in particular and if he was feeding it to all of his horses? He had chosen a product that was designed for maintenance level horses, not show horses or breeding stock. For horses working harder an added supplementation and proper feed rates would be imperative.

Although I was disappointed he hadn’t tried Nutrena products, I went on to ask if he followed the directions on the tag? He responded that he can never figure out all that garbage on the tag and fed his horses as he always does. There was part of the problem!

A feed tag will give you a statement of purpose, what type of horse and life style it is formulated to be fed. Next it will list the recommended feed rate. This can vary from 1/4 pound to 2 pounds per hundred pounds of body weight, depending on the fortification and quality of nutrients.

I was familiar with the product he had tried and their feed rate for horses working at a performance level would be 1.5 pounds per hundred pounds of body weight, or 15 pounds per day for a 1000 horse. This would have to be broken down into 3 feedings to be fed at a safe consumption rate, and could also mean added labor for his farm, not a bargain.

When I mentioned what I believed was the recommended feed rate for the product he was surprised. He said he would never feed that much of a concentrate to any horse. Again, he reiterated he doesn’t have time to read tags and do the math. I told him it is like making a box cake. You need to follow the directions, if you don’t use the entire box of cake mix, you won’t get the desired results. He did laugh at my remark, but I also think he understood the concept.

Does My Horse Need a Diet or Exercise Change?

I recently taught an Equine Nutrition class to a group of seniors at an area college.  Our focus for the classroom lecture was dietary assessment by body condition scoring, weight and topline evaluation.   After the lecture I conducted a lab to apply hands on practice of what we had just reviewed.

One of the students asked if we could evaluate her horse during the lab session. The evaluation proved to be a classroom classic. The horse was a 4 year old Warmblood gelding. He was 17.1 hands and 1350 pounds. The horse at first glance appeared to be round and in good flesh, but as I ran my hands over his withers and back you could feel a lack of muscle and coverage.hand feeding red size

I asked the student what the horse’s current diet consisted of, she replied 20 pounds of first cutting hay per day and 8 pounds of locally grown oats. The calorie content of the diet appeared to be sufficient, however the amino acid balance was lacking. The student also mentioned she had her saddle recently refitted and the chiropractor out because the horse was having back issues.

With the move to college, the horse’s workload had increased and the need for additional fortification was obvious. I suggested that the student purchase a ration balancer to balance the needs of the young horse’s diet and help replenish his topline.

One of the students in the lab then challenged my recommendation.  She stated that she was an Equine Physiology major and felt my diagnosis was incorrect. She felt that by working the horse in a more collected manner, engaging his hind quarters and coming up under him would help to strengthen and develop his topline. She thought he looked fat and did not need to change his diet.

I went on to explain that the horse’s current diet was similar to a young child that would be on a straight rice diet, which is deficient in amino acids. You would see a round abdomen, but lack of muscle mass. If that child were getting ready to compete in a marathon, I doubt running extra laps would increase muscle mass, unless we supplemented the diet properly.

Again, your horse will tell you what is lacking in his diet, if you just take the time to look.

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.

Does My Senior Horse Need Calories or Protein?

hand feeding red sizeThere are some common questions come up when we talk about what happens to horses as they age and why their bodies change shape:

  • Does my good old horse need more calories (energy) or more protein?
  • He is out on good pasture and is holding his weight, but his hair coat looks dull and he has lost muscle mass.
  • She looks a little thin, should I add some fat/oil to her diet?

These are all apparently simple questions, but actually we need to look at the nutrient supply and purpose a little closer.

Calories from fat/oil, digestible fiber (structural carbohydrates and starch & sugar (non-structural carbohydrates) are the key energy sources for horses. If a horse is thin, that tells us that the horse needs more Calories to maintain fat cover measured by Body Condition Score system. Those Calories can be added from extra fat/oil, extra digestible fiber or additional starch and sugar. Vegetable oil contains 2.25 x the Calories per pound of carbohydrates and is a safe way to add Calories. Switching to a highly digestible fiber source (better quality forage, added beet pulp etc.) can also add Calories of digestible energy (DE). It takes 2-3+ pounds of added feed to add 1 pound of gain, depending on the feed.

Adding Calories alone will not bring back the muscle mass. This will require added protein (really added essential amino acids, particularly lysine, methionine and threonine, the first 3 limiting essential amino acids). If a horse is getting adequate crude protein, but the protein is of limited quality and is low in one or more essential amino acids, the horse will not be able to utilize it fully to maintain or restore muscle mass. This is why it is essential to know the quality of the protein in feeds, particularly these first 3 limiting amino acids.

A common situation is an old horse retired to a grass pasture. It may be difficult for the horse to consume enough to maintain body condition, thus the horse loses weight. The grass pasture may also be low in crude protein and certainly low in essential amino acids, so the horse also loses muscle mass. Tough combination for an old friend!

The good news is that this can be reversed with the use of a well-designed senior horse feed providing both Calories and essential amino acids!

Selenium Levels for Horses

Selenium Levels for HorsesAs a horse owner, you may have heard about selenium levels and that you need to be concerned with them.  But why?

Technical reason: selenium is a key trace mineral in equine diets because it is a major component of glutathione peroxidase, which is an anti-oxidant enzyme, as well as several other enzymes.

  • Selenium also has an important interaction with Vitamin E.
  • Selenium and Vitamin E together are essential for both anti-oxidant benefits and for reducing the risk of certain muscle problems such as white muscle disease and exertional rhabdomyolysis syndrome.

Why you should care: Because selenium can also be toxic at higher intakes, it is also the only trace minerals regulated by the FDA.  Most of the U.S. is selenium deficient in soils (and thus toxicity is not an issue in those areas), but there are some areas with high selenium in the soil where some plants accumulate unacceptable levels of selenium in forage and may cause chronic toxicity. If you aren’t sure about the levels where you live, ask area horse owners, farmers, or your local extension office.

How much is in the feed?

In the case of selenium, the label guarantee, which is “added” selenium, is listed in ppm = parts per million = milligrams per kilogram. The actual content will be slightly higher as there is naturally occurring selenium in the ingredients. The labeling requirement is based on added selenium per FDA guidelines.

  • Premium horse feeds are commonly tagged at 0.6 ppm selenium, or 0.6 mg/kg of feed.
  • This equals 0.273 mg per pound of feed. (0.6 mg/kg divided by 2.2 kg/lb. = 0.273 mg per pound of feed)
  • Thus, if you feed 5 lbs per day of a 0.6 ppm selenium feed, you are providing 1.365 mg of selenium per day.

FDA requirement limits added selenium in feed to a maximum of 0.3 ppm concentration in total diet. This is why the maximum on complete feeds – feeds that include enough fiber to replace the hay/pasture portion of the diet – is 0.3 ppm.

On feeds which can be fed at a maximum of 50% of the diet (not that horse owners generally feed it that high), the limit is 0.6 ppm added selenium. Chronic selenium toxicity occurs at about 10X the FDA limit, so there is a pretty good safety margin.

How much does a horse actually need?

A horse’s basic daily requirement for selenium is 1-3 mg per day.  Some chronic selenium symptoms might appear above 10-15 mg/head per day.

To figure out what your horse is consuming, have your hay/pasture supply tested, and then add the amount it is consuming from the hay, to the amount it is consuming from any feed & supplements, and you will know if you need to make any adjustments to your horse’s overall diet.  Depending on your area, it may also be useful to consider intake from water sources.