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.

Starch Levels in Feed

In my previous blog post on this topic, we explored the role starch plays in the horse’s diet.  After (hopefully) warming you up to the idea of how useful this nutrient can be, I’d like to now dig in to how you can compare and contrast the varying levels of starch (and sugar*)  in feeds and hopefully this information will  help you compare and contrast to choose the best option for your horse.

Contrary to what you may have been told or read, most horses can tolerate a moderate level of starch each day.  If you have a horse that has been diagnosed with a form of equine metabolic disease, you will need to limit your horse to a ‘low’ controlled starch and sugar diet….which includes forage (hay and pasture).  Fructans, the sugars in forages, are too often overlooked when assessing the total diet of an EMS horse.  

Even if your horse has not been diagnosed with EMS, it is still important to understand the starch level in his diet and take it into consideration for your overall program. Think you know how to compare starch levels from one feed to another?  You might be surprised to find out that a bit of math is required. Simply comparing the percentage of starch on feed tags doesn’t quite tell the whole story.  To get to a true comparison, it is important to factor in the recommended feeding rate, which is, after all, what the horse experiences.

Let’s compare two feeds that are marketed as ‘low starch’; one has a starch maximum guarantee of 7% while the other has a maximum of 11%.  Pretty easy to tell which one is the lowest, right? 

Look beyond the percentage to find what's really in the feed

Not quite.  For our example,  let’s say we have a 1,000 pound horse at maintenance level activity.  Feed A, with 7% starch is recommended to be fed at a rate of 6 pounds per day, meanwhile, Feed B has a starch maximum of 11% and is recommended to be fed at a rate of 2.5 pounds per day.

Here is the formula to use:  Starch % * pounds fed/day *454 (converts to grams) = grams of starch fed/day

 

Applied to our example scenario, here’s how the math works out:

Feed A:  7% starch x 6 pounds fed x 454 = 190.68 grams of starch per day.

Feed B: 11% x 2.5 pounds of feed x 454 = 124.85 grams of starch per day.

Wow – a big surprise!  Not only is the 11% starch feed actually lower in grams of starch per day than the 7% product, the difference is actually rather significant given how different the percentages were.   It is important to keep in mind that it all comes down to what your horse actually ingests, so understanding the recommended feeding rate in pounds and then weighing your feed to hit that mark is what will make the difference.

It’s also important to understand that horses who do not experience a form of EMS have a higher tolerance for starches and sugar in their diet…and in fact, the performance horse will actually need those nutrients to support their activity levels.  It all comes to down to understanding what’s in your feed and how much you’re giving them.

*Though this blog article addresses ‘starch’ the same principles apply to determining the amount of other nutrients in a feed. 

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. 

Feeding “George”: A Polysaccharide Storage Myopathy (PSSM) Horse

Previously, I introduced you to George, my ‘Heinz-57’ PSSM positive horse.  Though his test results came back positive for Type 1 PSSM, his diagnosis does not mean his athletic career is over. With some diligence and routine, George is able to lead a normal life as a successful working partner.

One key to managing his condition is maintaining consistency in his diet and routine. Remember, he would get sore every time the hay changed, particularly if it had alfalfa in it.  First I work to ensure that George’s total diet is properly balanced which starts with controlling the starch and sugar energy sources in his hay and grain ration.  I buy larger quantities of grass hay (no alfalfa) that will last awhile, a full year if possible. I also have my hay tested before buying it to make sure it isn’t too high in non-structural carbohydrates (12% NSC or less), and that the rest of the nutrients are within an acceptable range for good quality hay, as this is the bulk of his diet. The lower the NSC in the hay, the more room there is in the diet to add calories from fat. More on that below.

To balance his hay, he gets a controlled starch feed concentrate that is fortified with essential amino acids, complexed trace minerals, pre- and probiotics.  If I need to add calories to his diet to support higher levels of exertion during training and show season, I add a balanced fat supplement to the concentrate component of his diet.  To meet the total caloric requirement it is recommended that PSSM positive horses receive no more than 10% of the digestible energy from non-structural carbohydrates (starch and sugar), and 15-20% of the digestible energy should be supplied by fat.  Remember, this applies to the total diet, contributions from grain plus forage.  Working with a qualified equine nutritionist is a great way to figure all of this out.  In a nutshell, I control the sugars and starches in his total diet (low NSC grass hay and low calorie, controlled NSC grain) and add a nutritionally balanced fat source when extra calories are needed. The only supplement he gets is vitamin E, which helps boost his antioxidant status (helps fight oxidative stress), and supports muscle recovery after exercise.  Because his total diet is balanced for selenium, I don’t supplement this mineral to avoid potential toxicity.

Estimating his weight and doing a regular body condition score help me adjust his diet and exercise routine accordingly, so he maintains good muscle mass and avoids excess fat deposits.  In addition, I make sure to minimize stress as much as possible by keeping his routine consistent.  His daily ration is divided up into 3 meals to avoid one large grain meal and he has access to hay for most of the day.  He gets a minimum turnout of 8 hours every day with a buddy and limited access to fresh forage.  I also exercise him at least 6 days a week.  With this management routine, regular veterinary and farrier care, he has never “tied-up” on me, and continues to excel in dressage with the occasional hunter pace thrown into the mix. Providing good quality of life is a top priority, especially when it comes to managing even the most challenging horses, and I think George would agree, he is doing great!

Prevention and Management of EMS in Horses

There is no treatment or cure for Equine Metabolic Syndrome (EMS), so taking preventative measures though diet and exercise are the best defenses against the development of EMS.

Crinkles on Toby's neck are evidence of his 'overweight' status

Here are some great defensive strategies to help prevent your horse from developing EMS:

    • Prevent obesity by providing a forage-based nutritionally balanced diet with controlled starches and sugars.
    • Maintain an optimal body condition through regular exercise.
    • Work with an equine nutritionist or veterinarian to understand what a healthy weight and body condition is for your horse to help prevent over-feeding or dietary imbalances that can contribute to EMS.

For horses who already are dealing with EMS, follow these tips to help successfully manage their condition:

    • Prevent or reduce obesity through controlled starch and sugar in the total diet along with exercise (unless horse is painful from laminitis episodes).
    • It is recommended that these horses have very little to no access to fresh pasture to avoid the overexposure to the sugars in grass.  Use of grazing muzzles or a dry lot are good alternatives to stall confinement, as this allows the horse to exercise on its own.
    • Have a nutrient analysis done on your hay to understand the NSC content – keeping in mind that it is important to understanding to NSC content of the total diet (hay + grain, if applicable).
    • Soaking hay (15 – 30 min warm water) can help leach out some of the sugars in the hay, just be sure to feed the hay right away before it spoils, and discard the sugar waste water, so the horse does not have access to it.
    • Low calorie ration balancers are good horse feed options to balance the diet if there are vitamin and mineral deficiencies from feeding a forage only diet, and/or from soaking hay.

 

 

Transition to Spring Pasture

It is no wonder these guys are asking to be let out onto the lush spring grass after such a long and trying winter.  What horse owner could resist those molten brown eyes and soft whisper-nickers, as if saying ‘Let me out, I’ll be good…I promise!’   

We work hard and do our best to provide our horses what they need; pasture seems all too natural to resist. It’s only when you understand the unique nutritional properties of early spring forage, that you can feel better about saying ‘not yet’!

If your horse survived the winter on hay, a hasty  introduction to ‘rich’ spring grass can cause a shock to his digestive system.  If at all possible, keep your horse off grass during the initial growth period by designating a ‘sacrifice’ area or dry lot.  The size of the dry lot will depend on your available land, but generally should be large enough to allow your horse to move about freely and stretch his legs. The sacrifice area serves to protect your emerging pasture as well as allowing you an opportunity to ease your horse’s digestive tract onto new-growth grass. If he is kept in a dry lot during this time, you may consider hand walking, lunging or additional work sessions to keep him from becoming too fresh. 

So what is different about spring grass that we should heed warning? As the strong spring sun warms the earth, the grass in your pasture emerges from its winter dormant state. The first few blades have a critical job of transforming sunlight into food, a process called photosynthesis, that starts the growth of the plant for the rest of the season.  This food is in the form of plant sugar (fructans) and is essential for the plant to grow into a productive pasture contributor for the remainder of the season. 

When overnight temperatures are cool (generally 40 degrees F) the stored energy created during the day is used to grow additional leaves and roots. Extra food not utilized overnight is stored in the plant tissues.  If overnight temperatures drop below 40 degrees F, the plant will not invest in growth and the sugars will remain in the leaves. This is when the new grass is of concern for horses.

Therefore, it stands to reason that when overnight temperatures remain above 40 degrees F, it is the ideal time to start acclimating your horse to the fresh spring grass, because the level of fructans in the grass are likely to be the lowest.

The transition to pasture should be slow and gradual, starting with a period of 15-20 minutes of grazing.  Gradually increase until you have reached your ideal turnout length of time; this may take the better part of a month.  During this time, it is important to monitor the output of your horse; loose, unformed stools indicate digestive upset likely correlated to the increased fructans. For horses with metabolic issues prone to digestive upsets, transitions should made later in the growing cycle onto mature grasses.  In addition to restricting time on pasture, a grazing muzzle can be used to further control intake.

I probably don’t need to tell you that a pasture full of healthy, green growing grass not only looks wonderful, it is  an investment in your horse’s nutrition. Allowing the early grass to grow and flourish, then gradually transitioning to grazing is an investment in your overall nutrition program. Armed with this information, don’t you feel better telling him to wait?

Colic, Laminitis & Starch Levels in Horse Diets

Many horse owners are concerned about carbohydratelevels in their horses diet, particularly if the horse is prone to colic or laminitis.  Often, the owner will look to simply feed a product with a lower starch or NSC percentage.  But that’s often not the best, or only, solution, particularly if elevated levels of performance are expected of the horse, because the percent of starch in the feed isn’t what matters to a horse’s digestive system – what truly matters is the total amount of starch that enters the digestive system per meal

When a horse consumes too much NSC in one meal, the starches and sugars may not be completely broken down and absorbed in the small intestine.  Undigested starch getting to the hindgut may cause rapid fermentation by the microbes (gut bugs) that live in the cecum and large intestine, which  results in gas production & lactic acid buildup.  The gas buildup can result in colic, while the lactic acid accumulation drops the pH of the gut, starting a chain of events that may compromise the blood supply to the hoof, resulting in laminitis.

Here’s the catch: all horses need some NSC in the diet to live and work for you – it is a simple biological need.  Hard working horses need higher, but still controlled, intakes of starches and sugars to provide readily available energy for work and to replace the glycogen (stored energy) that may have been used up during intense exercise.  NSC intake is important for horses to recover from hard work. 

If higher total intakes of starch and sugar are required to maintain energy levels, but the potential for digestive upset or laminitic episodes is a primary concern, the horse may benefit from more frequent but smaller meals during periods when extra calories are needed to recover from hard work.  The higher daily intake, using more frequent feedings, will provide additional starch and sugar, as well as other nutrients your horse needs, while helping reduce the risk of digestive disturbances related to higher starch intake in a single meal.

Types of Carbohydrates in Horse Feed Diets

The topic of carbohydrates for horses has gotten a lot of people asking questions and has created a certain amount of confusion, particularly when comparing carbohydrates in equine diets to human dietary recommendations.  Starches, carbohydrates, sugars, non-structural carbohydrates (NSC) and non-fibrous carbohydrates (NFC), among others, are terms thrown around for equine diets, and all those terms can get very intimidating, when it comes to what these nutrients mean to your horse  and how much your horse needs or doesn’t need. 

Here is a list of each of the common terms, and what they include:

  • Structural Carbohydrates – This category includes primarily the carbohydrates that are part of the cell wall in plants. 
    • This will include the Neutral Detergent Fibers (NDF), primarily lignin, cellulose and hemicelluloses. 
    • These carbohydrates are all fiber sources that give cell walls strength and shape.
    • Some types of fiber analysis, such as the Total Digestible Fiber (TDF) measurement used in human nutrition, will include the structural carbohydrates plus pectins, gums, beta glucans and some polysaccharides. 
    • These are the carbohydrates that are not broken down by enzymes and need to be fermented in the hind gut of the horse.
  • Non-Structural Carbohydrates (NSC) – This includes the sugars and starches, and is a very important group of nutrients for horses because these are the carbohydrates that can be broken down by enzymes and absorbed from the small intestine into the blood stream as glucose and stored as glycogen in the muscles and in the liver. 
    • Ideally, NSCs get absorbed entirely in the small intestine before they reach the cecum and large intestine, where they can be problematic for horses.  When people ask about a “low-carb” diet, they are frequently really asking about a low NSC diet.
    • Water Soluble Carbohydrates (WSC) – This includes ethanol soluble carbohydrates (ESC) which are primarily sugars, both monosaccharides and disaccharides.  WSC will include various oligosaccharides and polysaccharides.  Fructans in forages are included in the WSC.  When looking at a feed or hay analysis report, ESC should be a small proportion than WSC of the NSC.
  • Non-Fiber Carbohydrates (NFC) – This is a different nutrient which is calculated in certain analytical techniques.  NFC is equal to (100-Water-Ash-Fat-Protein-NDF).  NFC is calculated by difference and is not measured by a specific analysis.  NFC will contain all of the organic acids, starch, sugars, oligosaccharides, polysaccharides, beta glucans, pectins and gums.  For this reason, NFC will be a larger number than NSC in a feed or hay analysis report.

Carbohydrates in Horse Diets

There is a lot of discussion these days about carbohydrates, the good and the bad.  In reality, they are all related.  Carbohydrates contain carbon, hydrogen and oxygen in varied chemical relationships. 

  • Sugars are the simplest of the carbohydrates and can be simple sugars such as glucose or more complex sugars. 
  • Starches are strings of sugars linked together in such a way that most starches can be broken down into glucose by the action of enzymes, primarily amylase. 
  • Fibers (lignin, cellulose, hemicelluloses etc.) are also chains of sugars that cannot be broken down easily by enzymes and must be fermented by the animal to release the energy. 

Starches and sugars are produced by plants as a means to store energy, so they contain energy that is more readily available than the energy in fiber.

Because horses produce less amylase, the enzyme used to break down starch, than some other animals, say perhaps pigs, they are more limited in their ability to digest large quantities of starch. However, they digest smaller quantities very efficiently and very effectively! 

Starches and sugars are a fairly concentrated source of Calories to be used as a source of energy when extra energy is required to maintain body condition and do more work.  In the wild, horses would consume seed heads (grain) when available in the fall to help them gain weight (added Calories) to be ready for winter, so starches and sugars are a part of the diet in horses in the wild.  Today’s working horse requires Calories, and a combination of fiber, starch, sugar and fat can be the best way to support the horse to maintain the balance of optimal health and optimal performance.