Understanding Horse Nutrition, Part 5: Broodmares and Babies, Oh My

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Written By Dr. Kris Hiney

Over the last few months we have been discussing exactly how many calories (or megacals for those who are paying attention!) your horse needs to consume, depending on what activities he performs, his personality and what the weather might be doing.

Broodmares and babies.

We have yet to discuss an entirely different class of horses, the broodmares and babies. With the breeding season approaching, it is probably appropriate to talk about this special class of horses’ nutritional needs. While this article will focus on their energy requirements, remember, it is especially key for mom and baby to receive the correct amino acids, vitamins and minerals in the diet. These important nutrients are vital for proper growth and development, and ultimately the longevity or usefulness of your new arrival.

Megacals for Mom – before baby is born.

Let’s start with our expecting momma. Her energy requirements during her early pregnancy are not actually that much higher than a lightly worked horse. (Refer to Table 1 – ENERGY REQUIREMENTS FOR WORK). She should already be in good body condition if you have done your job of preparing your mare for her upcoming pregnancy (See Part 1 of this series, TOO FAT, TOO THIN, OR JUST RIGHT).

If you haven’t (shame on you) your goal is to get your mare to a BCS of at least 5 by the time she is at her ninth month of gestation (See CALORIES, KILOCALORIES, MEGACALORIES – HOW MUCH DOES YOUR HORSE NEED? for more information on increasing your horse’s body condition score). Otherwise, you want to ensure that your mare maintains that healthy BCS of around 5.5 -6.

Essentially the mare in early and mid gestation has lower energy requirements than a horse in light work, making her fairly easy to feed. You can usually support her increased energy needs by simply increasing the quantity of good quality hay. However, during the last trimester of pregnancy, her fetus is growing rapidly, which drives up her energy requirements to fall between horses in light and moderate work.

Table 4. Energy Requirements (Mcal/d) for Pregnant and Lactating Mares. 
Activity Time – tracking weight increase.

If you like being a very hands on horse owner (again – great youth project!), you can also track your mare’s increase in weight that is healthy for her and her foal. Using your weight tape (or string), check your mare’s increase in weight over her pregnancy. Overall, she should gain between 12-14% of her non-pregnant weight. She should gain around 5, 7, 10 and 13% of her original weight in her 8th, 9th, 10th and 11th month of gestation respectively. See Table 5 for a handy reference.

Table 5. The Expected Weight of Mares During Late Gestation by Month Compared to the Mare’s Original Non-pregnant Weight. 
Megacals for Mom – after baby arrives!

But look what happens after baby arrives! The new momma actually has quite the job to do in producing milk for her rapidly growing offspring. Her energy requirements have now increased by over 50% of what she needed during gestation. Compared to our working horses, your mare now almost reaches the energy needs of a racehorse of the similar size! Many horsemen often forget how demanding a job milk production truly is for your broodmare. Typically it is most effective to supplement your mare’s diet with a concentrate that is already specifically formulated for broodmares. Consult your local equine feed store or horse nutritionist for advice. This will allow her to meet her increased needs for other nutrients as well. While the broodmare definitely needs the extra calories, it is equally important that the diet is balanced to meet her protein, mineral and vitamin requirements to support lactation, and thus foal growth.

Feeding tips.

In order to provide a rough estimate of the amount of feed you will need for your mare, let’s work through a typical feeding strategy for a mare. We will work with a 1000 lb mare for simplicities sake. Now for both health and behavioral reasons, I encourage owners to always feed horses 2% of their horse’s body weight in hay or forage per day. We will actually visit the logic in feeding strategies in an entire article coming soon. For this mare, that means she should be eating 20 lbs of hay per day. I like to feed the pregnant mares and lactating mares a good quality alfalfa hay, in part to help meet their protein needs, as well as an increased need for calcium. Let’s use alfalfa hay which has a caloric density of 0.93 Mcal/lb fed. If we multiply the caloric content of the hay by the lbs eaten we reach her total caloric intake. 0.93 Mcal/lb * 20 lbs = 18.5 Mcal

Comparing our value here with Table 4 above shows us that the mare can consume enough hay to meet her energy needs. She just doesn’t need to consume that many additional calories. However, I would still recommend supplementing her with a ration designed for broodmares. Her energy intake is, of course, dependent on the mare consuming all the hay she is offered. Does she refuse to eat some of her hay and is therefore wasting it? Do you offer her hay free choice? If the hay is of high quality and is palatable to the mare, typically she will volunteer to eat more than 2% of her body weight per day. Also, remember the best indicator of caloric needs of the mare is her BCS. Keep an eye on her condition when changing feed intake.

Feeding when baby is here!

Now let’s compare our girl while pregnant to when she is lactating. Again, we will feed her the same amount of hay, so that she consumes 18.5 Mcal/d. However, during her peak lactation, she is now 10.4 Mcal short! What are our management strategies now? One easy strategy is simply to allow the mare to consume as much forage as she wants. These girls will often increase the amount of hay they eat per day in order to support their lactation demands. However, as mentioned before, we usually supplement these girls with a broodmare concentrate. Let’s use a grain mix with a calorie content of 1.3 Mcal/lb. (I’m using the energy value of a typical commercial feed designed for broodmares). To determine how many lbs of grain we would feed, divide the amount of calories needed by the calorie concentration of the feed. 10.4 Mcal needed/1.3 Mcal lb = 8 lbs of grain Ideally you would split her grain into two equal feedings per day. Now, while this is a fictitious scenario, most alfalfa hays and typical horse feeds will be similar in their caloric content. Read your feed tag for specific information on the feed you select.

Minerals of Note: 

While this month’s article is truly based on the energy needs of our ladies, I would feel remiss to not mention calcium (Ca) and phosphorus (P) when talking about broodmares. It is essential for proper bone development that these two key minerals are not overlooked. Not only do we need to feed adequate amounts of Ca and P, but they must be fed in the proper ratio. Ideally we want to see the ratio of Ca to P in the diet at approximately two parts Ca for every one part P, or 2:1. However, anywhere between 1:1 and 6:1 is acceptable. What you don’t want to see is the amount of Ca to extend beyond 6 parts or for your ratio to become inverted. In that case, you would have more P than you have Ca. Not sure how to figure it out? Let’s assume she is getting 105 g of Ca and 23 g of P from her hay. We would divide the g of Ca by the g of P, or 105/23 = 4.6. The ratio of Ca to P in this scenario is 4.6:1 which is acceptable. However, our girl will be short on P if she is receiving no additional mineral supplement.

Understanding Horse Nutrition, Part 4: Exercise and Energy Needs

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Written By Dr. Kris Hiney


In the last article, we tried to categorize exactly how much work your horse is performing, and how many calories he needs to consume to match his energy output with his energy input. If you have been following along our series, you now have determined how much your horse weighs, what his body condition score is (and what it might need to be), and how many calories your working horse needs at rest and during the period you are riding or training him. Again, we are focusing solely on the caloric part of the equation, realizing that work does indeed change the requirements of some other nutrients. However, if we do not meet our horse’s energy needs, no amount of supplementation will make up for the lack (or abundance) of calories!

Energy requirements regarding work.

This month we are going to discuss other factors that might change your horse’s energy requirements regarding work. This will almost wrap up our discussion of energy needs in horses. However, we still need to discuss the broodmares and babies, especially as the next generation is just around the corner! So let’s begin!

Categorizing your horse.

By examining the frequency, the duration and the intensity at which your horse works, you were able to put him into one of four categories described by the National Research Council – light, moderate, heavy or very heavy exercise. However, these distinct categories might not fit for every horse and some adjustments might need to be made. When in doubt, always refer back to your horse’s body condition to assess your feeding program.

Testing to determine energy requirements for exercising horses

To realize why your horse might not fit precisely into these categories, sometimes it is useful to understand how these numbers are actually derived. Energy requirements for exercising horses are actually based on determinations of how much oxygen the horse consumes during an exercise bout. Typically these studies are performed on a treadmill while a horse wears a mask over the nose. The amount of oxygen the horse takes in is compared to how much he breathes out. This allows one to calculate the amount of oxygen the horse used by the difference in oxygen concentration of inspired vs expired gases. The amount of oxygen the horse uses relates to the amount of calories he is burning.

Remember the TCA cycle I mentioned last month? This is where the carbohydrates, fats and proteins (sometimes) are “burned” at the cellular level with the assistance of oxygen to produce ATP. Horses, and people too, need energy in the form of ATP for muscle contraction. Thus, the harder and faster the muscles contract (ie speed or effort), the more ATP they need, so the more oxygen the horse needs to breath in. The amount of oxygen used directly relates to the fuels the horse uses to produce that ATP – the carbohydrates, fats, and proteins provided in the diet.

Exercise physiology break!

In order to accomplish an increase in oxygen delivery to its muscles, horses perform some rather amazing feats. One of the unique characteristics of horses is that they breathe in rhythm with their stride. Pay attention next time you ride to the blowing noise your horse may make while cantering or galloping. Right in time with their feet! Occasionally they will skip a breath in order to take a next bigger breath, but for the vast majority of the time, respiration rate and locomotion are linked. We call this phenomena stride coupling. So how do they get more oxygen if they can’t breathe faster? Well for one, if the horse is going faster, his stride rate increases and therefore increases his respiration rate. But he also breathes deeper as well. Essentially the horse takes a bigger breath – aided by the contraction and expansion of the horse’s ribcage as he runs faster and extends his stride. This makes breathing very efficient for the exercising horse. But that’s not all they do! Horses also have the ability to boost the oxygen carrying capacity of their blood. Red blood cells are responsible for picking up oxygen from the lungs, traveling through the body and delivering that needed oxygen to the working tissues. The more red blood cells present in the blood, the more oxygen that can be delivered. Horses have a unique ability to store their red blood cells in their spleen, waiting for the moment they are needed. When the horse exercises, adrenalin (epinephrine) is released into the blood, which causes the spleen to contract and eject all of these additional oxygen carrying cells into the horses blood stream. Instant (and natural) performance boost! .
Testing – testing – testing?

So why might these tests on a treadmill not always reflect the calories your horse needs? Well for one, galloping on a treadmill is relatively easier than working over uneven surfaces. The deeper the footing, the more exertion the horse will need to work. Think of running across an arena – it wears you out faster than running on pavement doesn’t it? Also, if your horse is being worked over hills (a great way to condition their cardiovascular system) this will increase its caloric requirement as well. We don’t typically have riders on top of the horses on a treadmill either. The weight of the rider and tack will also increase the energy demand on the horse.

A for effort.

There are other intangibles as well. The effort exerted by the horse also factors into the equation. Take for instance a jumper who routinely jumps his fences by over 5 inches versus the horse who barely skims over the fence. That horse over-jumping is working harder. The same can be said for almost every athletic event. Think about cutting horses, reining horses, barrel horses etc. The more athletic and talented the horse, the harder he tries, or the more effort he puts into each maneuver. Therefore, we may have a horse who spins faster, cuts a cow with more authority or finishes a barrel pattern with tighter turns and a quicker time. All of these factors affect his energy needs. Conversely, that lazy horse might be ridden the same amount of time as others, but may actually be expending far less energy than you think he might!

Gaits are hard work!

The gaits the horse performs can also influence its energy requirements. Typically a horse’s heart rate (which reflects its oxygen needs) increases linearly with speed (see Graph: Heart rate (bpm) vs speed). However, horses can travel at the same speed but be at different gaits. For example, think of someone long trotting a horse next to one that is cantering at the same speed. The horse that is long trotting or using an extended gait, is actually working at a higher intensity and using more oxygen than the horse cantering. The same is true for horses working at collected gaits. Thus, if your horse spends time working at both extended and collected gaits it may explain why they need more calories to maintain their weight than if we strictly account for the time they are ridden. For example, if you have watched dressage horses work at extended gaits, or watched an animated park horse travel around the ring, you can appreciate just how much work these guys are doing!

Keeping your eye on your horse.

Just as when we determined a horse’s maintenance requirements, climate, body condition and level of fitness will all affect the amount of calories that horse needs to consume. Remember, while feed tags, equations and tables all provide us with numbers to use in determining how much to feed a horse, they are just a starting point. There is no substitute for the horseman’s eye in evaluating the needs of your horse.



Understanding Horse Nutrition, Part 3: Energy Requirements For The Working Class Horse

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Written By Dr. Kris Hiney


In the last two articles we discussed evaluating your horse’s body condition and then determined how many calories your horse needs to maintain their weight. We discussed factors that will influence the horse’s “at rest” or maintenance requirements; including his condition, his personality, and the weather. This month we are going to talk about more active horses, the Working Class.

Be Realistic About Your Horse’s Workload.When we discuss how much energy, or calories, our horses’ need for work, we first need to be realistic about how much we are riding them. Just because we may be at the barn for quite a while, many overestimate the time the horse actually spends exercising. It may seem like we might ride for a good hour, but it might actually be quite less. I’ll use myself as an example. I might ride my young horses about 30 minutes per day, but I find it takes me three hours to ride just two horses! The time spent grooming them and chatting with your friends definitely can’t be counted in your horse’s workload!
Where Does Your Horse Fit?The National Research Council suggests four basic categories for work. These descriptors are light work, moderate work, heavy work, and very heavy work. First let’s discuss what these categories include, then later, what may alter these basic requirements.
Light Work.Horses in light work typically are not ridden every day. These horses may only be ridden 1-3 hours per week and usually at a slower pace. The majority of their exercise is performed at a walk or trot, with very limited time cantering. A good example of this type of horse is one that is used for light trail riding on a limited basis. For owners who have limited time availability to dedicate to their equine pursuits, they might find their horses fall into this category of work. Horses ridden at this level are typically the easiest to feed. The increase in their caloric needs is quite modest, increasing by only 20% over their “at rest” values. Horses that may only be ridden once per week or even less can really be treated the same as a maintenance horse. Riding a horse once every two weeks or so will not alter the energy needs of the horse significantly.
If you are unable to ride your horse multiple times per week, or even if you can, make sure your horse has adequate time to stretch his legs!  Horses which are stalled and not kept in a consistent riding program quickly become bored and may develop many unhealthy habits.   Horses naturally spend the better part of the day grazing and therefore moving at the same time. When we prevent these normal behaviors through confinement and don’t provide exercise, horses develop abnormal behaviors to help alleviate their frustration.  Stall walking, weaving, wood chewing and cribbing are all symptoms of a frustrated horse. So do those horses in light work a favor, and keep them outside if possible. Your horse will thank you for it.
Moderate Work.If you consider an active training schedule for most horses, we would expect to ride the horse on average five days per week. Typically, these horses are being physically conditioned for an event or are in some sort of consistent training process (even if the training is more for the rider. Expect the horse to be ridden between 3 to 5 hours per week and to do more intensive exercise. Horses will spend more time at a trot or canter, and may be performing more specific skill work. This could include jumping low fences, beginning work on barrels, dressage maneuvers, etc. Most of our performance horses which don’t engage in strenuous activity but are ridden regularly fit the category of moderate work. To meet these horses’ needs, typically the amount of calories the horse consumes would increase by 40%.
Heavy Work.The horses in heavy work will be ridden a similar number of days per week, and perhaps even for the same duration, but the intensity of the exercise has increased once again. The horse may work at a faster gait, such as a much faster canter or gallop, or their effort in work has increased. The horse’s may be jumping larger obstacles, performing longer, or running faster. Examples of horses in heavy work would include reining horses, three day eventing horses, jumpers, polo horses, or even ranch horses. One major difference between the horse at moderate work and heavy work is usually the addition of anaerobic activity. In general, if a horse is working at a level in which its heart rate is over 150 beats per minute, they are using their anaerobic energy systems. For instance, in reining horses, the fast circles, spins and stops of a trained horse will cause the heart to beat at 150 beats per minute or greater. Horses in the heavy work category will generally need an increase of 60% over their maintenance requirements.
Aerobics for Horses?

When describing work intensity, exercise physiologists use the terms aerobic vs anaerobic work.  Technically aerobic work is at a low enough intensity that the muscles of the animal can rely on the slower metabolic pathways. You may remember learning about the TCA cycle or the Kreb’s cycle in previous schooling. That is the aerobic energy systems. Its job is to provide the energy source for muscle contraction – a little molecule called ATP. All dietary energy sources; fats, carbohydrates and protein can be utilized in aerobic metabolism.  The word aerobic means that these fuels are burned in the presence of adequate amounts of oxygen.  That means that the horse’s heart and lungs can keep up in the race to deliver oxygen to the tissues.When the horse’s muscles are contracting faster or harder than the ability of the cardiovascular system to keep pace, they then enter into anaerobic metabolism. The horse must then switch to a different supply of fuel, primarily carbohydrate metabolism.  They are simply working too hard for the aerobic system to keep up with the demands of the muscles for ATP.  Don’t worry too much about the details right now, we will spend more time with these topics in later issues.
Very Heavy work.The last category of work intensity probably has the fewest numbers of horses within it. These are our race horses, whether they are Quarter Horses, Thoroughbreds, Standardbreds, or even endurance horses. They have quite the job to do, and need the fuel to do it. While their training schedule may be a bit more varied than the previous two categories, the level at which they work raises their energy requirements to almost twice that of their energy needs at rest. Maintaining the proper caloric intake in these horses and keeping them at the proper condition can potentially mean the difference between win, place or show.For next month we will discuss other factors that might change your particular horse’s energy requirements for work. And we certainly can’t forget to mention the growing horses and the broodmares! For now, try to determine what work load your horse is in, and look up its caloric requirement below, in Table 1. Energy Requirements For Work. And remember, be honest!
Table 1. Energy Requirements For Work (Mcal/d).

Wt of horse (lb)LightModerateHeavyVery Heavy
Quick Tip!While we haven’t discussed caloric intake sources (coming soon), a great way to increase calories is to add safe fat to the diet. Fat has 2.25 x the amount of calories per lb compared to anything else we can feed our horses. Add safe fat sources made with stabilized ground flax seed (rich in Omega-3 essential fats) and/or stabilized rice bran (rich in powerful antioxidants and Omega-6 essential fats) – Omega Horseshine®, Omega Antioxidant, Omega Grande®, Omega Stabilized Rice Bran, or the horse treats that Horse Journal™ named: “Best Buy” – Omega Nibblers®. These supplements add calories quickly and safely.Watch for January’s Health-E-Letter when we will talk about EXERCISE AND ENERGY NEEDS – WHAT IF MY HORSE DOESN’T FOLLOW THE RULES? – Part 4 in my Understanding Horse Nutrition: How to Achieve Maximal Performance From Your Equine Companion series.

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Understanding Horse Nutrition, Part 2: Calories, Kilocalories, Megacolories–How Much does your Horse Need?

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 Written By Dr. Kris Hiney
Energy means calories!Last month we discussed your ability to evaluate your horse’s body condition, and what the optimal condition for your individual horse may be. This month we delve a little further into the energy requirements for horses. Remember – when referring to energy, we mean calories! As stated last month, it does not mean how your horse feels. There are many other factors that influence your overall horse’s attitude, and while certainly how many calories he consumes is part of it, it isn’t the entire picture.
Let’s talk technical.

In the equine world, due to the horse’s body size, we talk about their energy requirements in megacalories (Mcal). One Mcal is equivalent to 1000 kilocalories (kcals). To make it relatable, the average woman between 31 and 50 years of age who is moderately active is recommended to consume 2000 kcal/d. That would be equivalent to 2 Mcal for a horse.

How much energy (or calories) does your average horse need to consume per day?Well, first we need to define even what average is. When we discuss energy requirements, we usually begin with the animal’s maintenance requirements. Maintenance is defined as a mature horse not undergoing any exercise program or reproducing. Essentially the average, older horses just out hanging around. Numerous researchers have studied the energy requirements of horses, and as a result we have equations to calculate exactly how much a horse needs to eat. For example, the maintenance requirement of an average 1,050 lb horse would be 14.5 Mcal/d. These numbers are derived from the body weight of the horse multiplied by the energy required to maintain one kilogram of that horse’s body weight.But even average is not always average. The defined maintenance requirements for horses are based on horses in a moderate condition – those horses between 5 and 5 ½ we talked about last month. If your horse is overly fat, he needs less energy to keep him at the same weight. Fat tissue is metabolically less active than lean tissue, or muscle. Therefore, a 1,100 lb horse who is fat actually needs to eat less than a 1,100 lb fit horse to maintain the same weight.
Where do these numbers come from?

For those truly interested, the results of equine nutrition studies have been combined into a lengthy document entitled The Nutrient Requirements of Horses edited by the National Research Council (NRC). Teams of scientists world-wide review the collected work of all researchers to create recommendations published in this document. Animal nutritionists use “NRCs” to determine the nutrient requirements of all species of livestock and companion animals. The latest NRC for the horse was published in 2007 and is available through the National Academies Press (www.nap.edu). If you would like to calculate your own horses requirements from scratch, this book will provide the equations to do so.

Understand the important goal. Now, the point of this discussion is not to have you whip out your calculators and revisit your algebra and calculus days. The important goal is to understand what factors we have control over that will alter how much energy our horse needs. Then we will discuss how best to meet these energy requirements to optimize your horse’s health and performance.
Easy keeper or not?Even your horse’s overall temperament will change its energy requirements. We have long known that hotter, or more nervous horses take a lot more feed to keep weight on, while those with a more laid back attitude need less feed. Typically those horses that were selected to have a more laid back personality, such as our stock breeds or draft horses, fall into that easy keeper category vs our horses who were selected for speed (think Thoroughbreds).On average, a more active horse (youngsters in pastures, nervous Thoroughbreds) will need 20% more energy than an inactive horse to maintain its weight. So let’s say we have a 1,100 lb laid back, fatty American Quarter Horse vs an active, lean 1,100 lb Thoroughbred mare. Our laid back horse needs 14.8 Mcal/d while our active girl requires 17.8 Mcal/d (see Table 1 to estimate your horse’s maintenance requirement). She will need to eat 3 Mcal/d more than our couch potato. That’s even before we start working her!
Table 1. Energy requirements for maintenance (Mcal/d) based on average activity level.

Wt of horse (lb)Couch potatoAverageActive

The second major variable in the maintenance requirement for a horse is the weather. The calculated maintenance requirements are based on an environment that requires no energy by the horse to keep themselves warm. We call this the thermoneutral zone. Horses do quite well in cold temperatures if they have become accustomed to them. Cold adapted horses do well in temperatures as low as 5º Fahrenheit (F). However, horses will have trouble keeping warm if the weather suddenly changes and if the horse hasn’t grown the proper hair coat. But all horses, even fuzzy Wisconsin ones, will have trouble if they do not have protection from the wind or from rain, especially sleet. This chills a horse rapidly when the fluffy, protective insulation of their hair coat is slicked down to their body.

How much energy does a horse need to stay warm? Below 5 º F, a horse needs to use energy to keep warm, and that temperature is referred to as the lower critical temperature. (Which is nothing for those of us living up here in the Northern Midwest – brrrr). So how much energy do they need to stay warm? On average, for every drop in temperature of 14 º F below the lower critical temperature, they will need 20% more energy. Let’s say the temperature drops to -10 F º and we are feeding our energetic girl. She will now need 21.4 Mcal/d for maintenance, an increase of 3.6 Mcal/d over her normal maintenance requirements.
Gaining weight for insulation.

There are additional strategies we can take to prepare our horses for winter weather, other than providing adequate shelter and letting them grow a hair coat. Adipose tissue, or fat, helps insulate horses against the chill of the winter weather, just like in polar bears. Now let’s say our higher strung mare is also thin, about a condition score 4. Well, clearly we would like to put some weight on her, especially before Old Man Winter arrives. To change body condition scores in horses by 1 value (ie a 4 to a 5), we have to really start feeding them, especially if you want to put that weight on more rapidly. If our goal is to put weight on the mare in as little as 60 days, we would have to increase her caloric intake by 5.3 Mcal/d, or 30% of what she was consuming. If our goal is a little more gradual, let’s say over 4 months, her diet would be increased by 2.7 Mcal/d or 16% of her current intake.

Not sure how much your horse weights?

Weight tapes are available at most feed stores at a fairly nominal price ($2-3). But for even more fun (great for kids and 4-H activities) you can do it yourself with a string and a measuring tape. Use one string to measure the distance around your horse’s heartgirth (HG). Make sure your horse is standing square and your string is around your horse perpendicular to the ground. Then measure the length of your horse’s body (BL) from the point of his shoulder to his buttock, just like you were measuring for blanket fit. Again, be sure your horse is square and that your string is held level to the ground. Measure your two strings in inches using your tape measure. Then use this simple formula
Wt of your horse (lbs)= (HG)2 x BL
330 Wallah! Now you know how much your horse weighs!
Quick tip.While we haven’t discussed energy sources (coming soon), a great way to put weight on horses is to add fat to the diet. Fat has 2.25 x the amount of calories per lb compared to anything else we can feed our horses. Need to put weight on before winter? Check out some fat added feeds, or add safe fat sources made with stabilized ground flax seed and/or stabilized rice bran — Omega Horseshine®, Omega Antioxidant, Omega Grande®, Omega Stabilized Rice Bran, or those famous Horse Journal™ recommended horse treats Omega Nibblers®. These supplements add calories quickly and safely and are better than just increasing how much your horse is eating.

Understanding Horse Nutrition, Part 1: Too Fat, Too Thin, or Just Right

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 Written By Dr. Kris Hiney
Horse nutrition can be a complex issue. We can feed horses to maximize stamina and power, prevent digestive disorders, avoid metabolic disorders, prevent attacks caused by genetic diseases, grow horses to be sound throughout life — the list goes on and on. Trying to wrap one’s mind around all of these issues can be intimidating at best, even for equine nutritionists, let alone the average horse owner. However, we will begin with the basics, and then build to more complicated ideas.

This month we begin our series on Understanding Horse Nutrition: How to Achieve Maximal Performance, with Part 1 — TOO FAT, TOO THIN, OR JUST RIGHT? We will be discussing the proper weight or condition for your horse depending on its career. We will then put together these ideas to determine the amount of energy we should be providing to our horses. We will conclude our energy talk with the most optimal way to provide energy to your horse to gain that competitive edge. In future months, we will discuss common horse diseases and disorders that are impacted by our feeding strategies.

One of the easiest nutrients to be fed to horses is not a nutrient at all – but energy. Ironically, energy is often the most commonly misunderstood. When horse nutritionists talk about energy, we simply mean calories. Energy to your horse can be supplied in many ways, from carbohydrates, fats or proteins. All of these can be utilized for your horse for fuel.However, when many horse owners refer to energy, what they really mean is how their horse feels. Does he seem lethargic, or does he come bouncing out of his stall or paddock? While how the horse feels can be impacted by how many calories it receives, there are many other factors that contribute to the overall health or attitude of the horse. But certainly improper management of the calories the horse is receiving can alter your horse’s demeanor.The idea seems simple enough, we feed horses enough so they are neither fat or skinny, right? Pretty much, but of course there has to be a little bit more to it. Exercising horses need more energy, sedentary horses need less. Some types of horses need more feed to put on weight, while the “easy keepers” could exist on air. We all know this, just from our own life experiences. So why do so many horse owner’s struggle with achieving that perfect weight in their horses? Is there a perfect weight? What’s good for one type of horse may not be good for others.

Body Condition Scoring – from 1 to 9.To better define the energy needs of horses we will look at the idea of body condition scoring in horses. The body condition scoring system for horses is a numerical system used to assign a number to describe the fatness of a horse, or how much energy he has stored on his body. The system that is most often used today was created in the 80’s at Texas A&M University. Horses are assigned a number from 1 to 9, with 1 being extremely thin and 9 obese. This system of assigning numbers with the degree of fatness allows veterinarians, equine nutritionists, barn managers and trainers a common language to describe the best condition for horses to be for their optimal performance. The system is even used in court to prove cases of animal neglect and abuse. You may be familiar with similar types of systems, as they are frequently used in other livestock, and even with our in-house companions, cats and dogs.
Fat – seeing and feeling.

In horses, we examine eight parts of the animal’s body, both visually and manually, to come up with an overall body condition score (See Figure 1). The six main areas to examine are over the crest of the horse’s neck, their withers, behind their shoulder, over their ribs, the crease on their back, and their tailhead. Examining all areas of the horses’ body gives us the best idea of the condition of the animal, by taking the average value. Just like in people, some horses carry fat preferentially in different parts of their body. Sometimes where the fat is located can be an important indicator of potential metabolic problems (more on that in upcoming months!). Taking all parts of the horse into consideration is key in determining the condition score of the horse.

A horse that is average in their amount of fat is given a value of 5. If your horse scores a 5, his back should be level, you can’t see his ribs, but you can easily feel them; the withers appear rounded over the spinous process, and his shoulders and neck blend smoothly together. A horse with a score of 4 has a negative crease down it’s back (essentially the upper portion of the vertebrae are not surrounded by fat and stick up), and the ribs are faintly seen. In these horses, the withers, shoulders and neck are not obviously thin. As we go lower in body condition score, the horses appear more and more emaciated. On the opposite side, horses that are above a five begin to have a crease down their back, the ribs begin to be harder to feel, and fat gets deposited along the withers, the sides of the neck and behind the shoulder. As horses increase in fatness, the crease down the back gets deeper, fat develops up and around the tailhead, and the horse essentially loses some of the contours of its body as fat fills in.

So what body condition should you shoot for?It depends. For most exercising horses and healthy, mature horses, a score of 5 to 5 ½ is ideal. These horses will have sufficient energy reserves for work but not be impaired by excessive weight. Condition scores above 6 are generally not recommended due to the extra stress upon the bones and joints of the horse. Excess fat can also impair a horse’s ability to dissipate heat. Therefore, in horses that undergo longer periods of exercise (think three-day eventing horses, endurance horses etc.) and need a greater ability to thermoregulate, the most successful athletes range between a 4 and a 5.
Aim a little higher for breeding horses.We encourage mare owners to allow the girls to enter the breeding season at a score of 6 or 7. Mares at a score of less than five have more reproductive challenges, with delayed time of their first successful heat cycle, needing more cycles to conceive and a reduction in pregnancy rates. The boys are also encouraged to enter the breeding season at a healthy weight, as the stress of breeding season in a heavily booked stallion can cause him to lose weight.
Prepare older horses with sufficient weight for the season.

If possible, owners of older horses are also encouraged to allow them to gain additional weight prior to winter. If older horses are housed outside without adequate shelter, the energy needed to keep themselves warm may cause a drastic loss in weight. By preparing them for the season with sufficient weight, these horses have more insulation, more energy reserves, and can go through the winter season more easily.

“Hands on” time with your horse!So go out and take a look at your horses and try to give them a score. But don’t forget to get your hands on them, if you really want to know the answer!


Fun With Feed Math! Part 4: Using Feed Tags

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 Written By Dr. Kris Hiney

We have talked about what information should be included on a feed tag, regardless of type of feed. In this article we will put that information into use to aid you in selecting the best (and perhaps most economical) feed for you to use. So let’s start with what the guaranteed analysis means to you.

Crude Protein- The amount of protein in horse feed is often the most talked about, but most misunderstood component of horse feed. Owners often select their horse feed solely on the percent protein with little consideration to other vital components of the diet. While protein is important, it is certainly not the only criteria by which you should select your feed. Horses need the amino acids contained in protein for maintenance as well as synthesis of body tissues such as muscle, bone, organs etc, as well as synthesis of hormones and enzymes necessary for body function. Horses which need more protein in the diet are those that are busy synthesizing more tissue such as growing horses, broodmares and lactating mares. Horses that are mature and not at work (our maintenance horses) will require the least amount of protein. For example, a 1100 lb maintenance horse will require between 540 g and 720 g of crude protein in the diet per day. The range in those numbers are due to differences in temperament (more or less active horses), environment etc. Using your feed tag, you can determine how much protein your horse is receiving. Let’s assume you selected a feed that contains 12% crude protein and you feed 4.5 kg or 10 lbs of feed (to learn to convert to lbs see below). Multiply the percent protein by the amount fed to determine the amount of protein provided.12% or 0.12 x 4.5 kg = 0.54 kg.12% or .12 x 10 lbs = 1.2 lbsYour horse is thus consuming 0.54 kg or 540 g of protein by eating that amount of feed. Now, don’t forget, the horse will also be receiving protein from the forage in his diet as well. Now compare that to the horse’s protein requirements. For a maintenance horse, he has already almost met his requirement even before we consider his hay! To determine where your horse fits in the chart, see Energy Requirements for the Working Class. Then use Table 1 below to find his protein requirements.

Table 1. Crude protein requirements in grams for horses of varying work intensities. These numbers are derived from the National Research Council, Nutrient Requirements of Horses. 2007 edition.
Work Intensity
Wt of horse (lbs.)MaintenanceLightModerateIntense

Most equine feeds will contain protein in a range of 8-16% of crude protein, with those higher in protein designed for the young growing horses or broodmares. Some feeds might be higher in protein, if they are designed to be a protein supplement, versus a typical concentrate fed for energy.

Math Time

Pounds versus kilograms. Many horse owners are often frustrated by the different units provided by feed tags, nutritionists, books etc. In our protein example I have provided the horses requirements in grams. However, most individuals in the United States think in pounds. So let’s learn how to convert back and forth shall we! To convert grams to pounds, remember that there are 1000 grams in every kilogram. So using my numbers above I would take 540g and divide by 1000 to convert to kg. Therefore, my maintenance horse needs between 0.540 kg and 0.720 kg of protein per day. Now, changing from lbs to kilograms is fairly easy. One kilogram is equivalent to 2.24 lbs. Many times we will round down to 2.2 lbs/kg for simplicities sake. Now let’s convert our numbers from above.

.540 kg x 2.2 lbs/kg = 1.2 lbs.

.720 kg x 2.2 lbs/kg = 1.6 lbs.

To covert lbs to kg, you simply do the opposite, and instead of multiplying, you would divide by 2.2. If I had 5lbs of feed, and wanted to convert it to kg, I would use the following equation: 5 lbs ÷ 2.2 lbs/kg = 2.3 kg. Remember, numerically, the amount in kgs will always be less than it is in lbs. For example, an 1100 lb horse is equivalent to a 500 kg horse.

Crude Fat –Those horse owners looking for more bang for the buck should pay attention to the crude fat in their horse feed. Addition of supplemental fat to a feed greatly increases the amount of calories in a feed. This is important as fat is a very efficient and safe way to add energy to a horse’s diet compared to adding traditional grains, such as corn and oats. Horses do quite well at digesting fat, and as long as it is not fed in excessive amounts (over 20% of the diet), find it tasty as well. Typically, a non-fat added feed will contain less than 4% fat, with those feeds with additional fat containing between 6 and 15% fat. But what about Omega Horseshine®, which last month I showed you contained 30% fat? Well, that is because Horseshine® is not a traditional concentrate but rather a specific fat supplement. As its primary ingredient is flax seed (37-40% fat), we would expect that this product would be much higher in overall percent fat. Be sure to refer to back to Equine Energy Requirements to decide if your horse would benefit from a fat added feed.
Crude Fiber- Crude fiber is often used to reflect the amount of energy in a horse feed. Typically, fibers will contribute less energy to a horse’s diet than do low fiber feeds such as grains. Low fiber feeds usually will then contain more soluble carbohydrates and thus energy. For example, corn is typically 10% fiber and has 3.9 Mcal/kg while grass hays can range between 50 and 70% fiber and will contain between 2 and 2.3 Mcal/kg (all numbers are expressed on a dry matter basis). Thus there is typically an inverse relationship between fiber and energy content. Even between typical grains fed to horses we can have a significant variation between fiber content. Let’s compare oats versus corn. Oats, which are often thought of as a safer feed for horses, typically contain between 30 and 40% fiber due to the presence of the hull, and thus contribute only 3.2 – 3.3 Mcal/kg to the horse.
Fiber and the 21st Century Previously it was quite easy to predict the energy content of concentrate feeds for horses based on the fiber content. This relationship still exists, provided the feed contains less than 12% crude fiber. However, many equine feeds are now formulated to contain much more fiber, as researchers have discovered many downsides to feeding high starch diets to horses. Higher fiber feeds usually also have the addition of fat, which offsets the lowering of caloric content by choosing less nutrient dense feeds. Horse feeds that contain beet pulp, alfalfa meal, soybean hulls etc will often be higher in fiber, but coupled with rice bran or flaxseed for the added fat boost of energy.
Calcium and Phosphorous –We will discuss these two very important minerals together. The amount of calcium and phosphorous in the diet is absolutely critical for growing horses and broodmares. These animals are rapidly forming bone which will be crucial for a sound, productive life. Imbalances of these nutrients in your broodmare’s or foal’s diet can cause permanent changes in bone and cartilage which can lead to painful developmental problems in the future. Expect that feeds designed for these classes of horses will be higher in calcium and phosphorous than those designed for maintenance horses. We discussed previously in our article, Broodmares and Babies, the idea of the all important calcium to phosphorous ratio. Remember, you should never have more phosphorous in the diet than you have calcium. At a minimum, you should have a 1:1 ratio between calcium and phosphorous, with a ratio of 2:1 in favor of calcium more ideal. However, I can’t stress this enough, remember, that your horse’s diet does not exist solely of the feed you choose, but also the forage! Always try to select your horses’ concentrate with consideration of not only it’s class, but also what you base the horse’s diet on –it’s hay!
Copper- Copper is an important mineral needed by horses for the function of many key enzymes. It plays an important role in the formation of collagen, and thus is critical for proper joint development in young horses. Copper also aids in iron metabolism as well as the elimination of free radicals in the body. However, it is needed in much smaller amounts than Ca and P, and thus is referred to as a micro-mineral. Its concentration in your feed will be listed in the units ppm or parts per million. An equivalent way to think of Cu concentration would also be mg/kg, as there are 1 million milligrams in every kilogram. Let’s use Horseshine® once again. Looking at the label, we can see it contains 116 ppm Cu. If you fed one half pound of this supplement per day (or 0.5 lbs ÷ 2.2 lbs/kg = 0.227 kg) your horse would be receiving 0.277 kg of Horseshine®. To determine the amount of Cu the horse is eating, multiply the amount fed by the concentration in the feed, just like we did for protein.0.277 kg x 116 mg/kg = 26 mg of copperTherefore, Horsehine® is adding 26 mg of copper to your horse’s diet per day.
Zinc –Zinc, like copper, is considered a micro-mineral, and is also listed in parts per million on the feed tag. It plays a similar role in aiding in enzyme function, but in such a wide array in the body as to be too numerous and diverse to mention. It is frequently added to commercial equine feeds due to the variability in hays and forage. Using our same serving of Horseshine, zinc is listed at 321 ppm. Thus, the horse gets 89 mg of Zn with every serving (0.227 kg x 321mg/kg = 89 mg).
Selenium –Selenium is often one of the most commonly discussed minerals is horse nutrition, mainly due to its essential function in the immune system and role as an anti-oxidant, but also due to its tremendous variability in feeds across the country. In the United States, some regions are considered selenium rich and some selenium deficient. Thus forages or hays produced in different areas can vary from selenium deficient to even reaching toxic levels of selenium. Even weather conditions can cause alterations in Se content of feed, as drought conditions can greatly increase selenium uptake by plants. Overall, selenium may certainly be needed to be supplemented in the equine diet, but in much lower concentrations than even Cu or Zn. Most feeds will vary in the range of 0.1 to 0.5 ppm of selenium in order to meet the horses’ requirements, but to avoid any toxicity issues.
Vitamin A- Vitamin A is needed by the horse in much larger quantities compared to other vitamins. Horses consuming green forages (grazing horses) typically meet their needs quite easily. However, horses which consume a primarily harvested forage diet (hay) might have a possibility of becoming deficient, especially if the hay has been stored for a great length of time. The vitamin A content of hay does decrease over time, with a large percent of all vitamin A lost over one year’s storage of hay. Thus, most commercial feeds are supplemented to ensure adequate intake by the horse.


Fun With Feed Math! Part 3: Ulcers: Is Your Horse Stressed

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Written By Dr. Kris Hiney

The last article briefly discussed the horse’s gastrointestinal system and the challenge it presents to feeding management. This month we will discuss a specific disorder, equine gastric ulcer syndrome. Just like us, horses can suffer from painful gastric ulcers which can lower their performance ability, and certainly their overall health and well being. Due to their unique physiology they may be even more susceptible to ulcers than other domestic animals. Symptoms of ulcers include decreased feed intake, lowered performance, a rough hair coat, laying down excessively or even grinding their teeth.

GI Tract Again

When wondering why horses seem to be so prone to ulcers, it is important to really think about what their digestive anatomy is designed to do. In the stomach of the equine, there are two regions, a glandular region which secretes hydrochloric acid and digestive enzymes, and a non-glandular region in the upper or proximal part of the horse’s stomach. The mucosal cells of the horses glandular portion are well suited to protect against the acids that would normally be present in the horse’s stomach. However, the cells in the non-glandular region are not as protective, and repeated exposure to digestive acids can result in creation of lesions in the stomach. Now normally, this is not a large problem for the grazing horse. When a horse is eating continually, they will be constantly producing saliva with buffers that serve to increase the pH in the horse’s stomach, and prevent any damage to the mucosa. When horses are not eating, no saliva enters the stomach, and the pH begins to drop. This can occur within 5-6 post eating. As stated last month, if your horse remains without feed for 10 hours, his stomach will be completely empty, and the pH drops even lower. Foals are especially susceptible, and any foal that goes off feed due to illness may end up with a secondary problem of ulcers. Look for your foal to be grinding their teeth or lying on their back. These are classic signs of ulcers in foals.

Is Grain the Problem?We also see an increase in ulcer prevalence in horses that are on high grain diets. Now this may actually be due to a combination of factors, which we will see soon. But high concentrate feeding itself can be a culprit. When horse’s are fed concentrates, either in the form of pelleted or whole grains, the amount of time a horse will relatively spend consuming that feed will be less than that on long stem forage. It simply takes less “chews” to eat a pound of grain vs a pound of hay. Less chews equal less saliva production as well as a longer interval between the next feeding (ie he finishes faster). In addition, concentrates themselves cause production of a different type of volatile fatty acid production in the stomach. While the hind gut was long considered the sole domain of fermenting bacteria in the equine, we now know that isn’t true. Microbes do indeed exist in the stomach of the horse, and some types will flourish on a higher grain diet. This particular bacteria result in production of more acidic waste products, which further decrease your horse’s stomach pH.
What Else is Going Wrong?As I said earlier, it may be incorrect to point the finger solely at feeding horses high amounts of concentrates. After all, what types of horses consume large amounts of concentrate? Hopefully you remember from our earlier series which types of horses need high amounts of Mcals. These are typically heavily working performance horses that need the grain in the diet to meet their caloric needs. But what else is unique about these guys? One, they are exercising more, which in itself may help contribute to the problem. When horses are galloping, the abdominal contents of the horse are essentially “squished” forward as the hind legs reach up under the horse prior to the forelegs reaching back forward. This forces the more acidic contents of the glandular portion of the horse’s stomach up into the less well-protected non-glandular region.Secondly, performance horses are frequently stalled individually. It is simply a fact of the matter that these horses must be kept blemish free and protected from too much rough play with others. Some horses even have an aptitude to hurt themselves when playing on their own too vigorously. However, stalling can be a source of mental stress for horses, as it eliminates their natural tendency for continual movement throughout the day, as well as their foraging behavior. It also removes the horse from its natural desire to be a herd animal. Horses in the wild are never seen in isolation, unless they are sick or injured. Therefore, isolation can be extremely stressful for some horses.

Another leading cause of ulcers is the use of non-steroidal anti-inflammatory drugs or NSAIDS. These drugs block an enzyme necessary in the pathway that produces prostaglandins that cause inflammation. However, as these drugs are not specific for blocking production of only one type of prostaglandin, they also block formation of the prostaglandins which help maintain gastric mucosal integrity and are anti-inflammatory. Therefore, long term use of NSAIDS can almost certainly cause ulcers in horses, and is typically avoided unless necessary. However, the rigors of training and exercise may cause theses horses to be provided NSAIDS more frequently than horses in only light or recreational riding.

Even the career of your horse may be stressful. Racehorses have a much higher incidence of ulcers than other types of performance horses, but again this could be attributed to many factors: high concentrate diets, stalling, exercise etc. Even transport has been reported as ulcer inducing. In a group of thoroughbreds, transport for 6 hours was reported to increase the prevalence of lesions in the stomach, however this was not observed in western performance horses. I would propose that simply the personality of the horse plays a large role. Is your horse a fretter and a worrier or one that could happily march through a parade without batting an eye? After all, ulcers are more common in us type A individuals than our more laidback neighbors!

Prevention.One of the easiest ways to control the incidence of ulcers in horses is to alter our management strategies. Feeding horses at more frequent intervals, or providing meals of long stem forage at an amount to prevent an absence of feed availability is ideal. That may mean spreading out the feeding interval to 12 hours or by providing your horse with a larger evening meal to last closer to breakfast. Also consider the type of feed you are using. Long stem forage will cause a horse to chew for a longer period of time, compared to pelleted rations. Horses that are on complete feed are especially more likely to be “out of feed” for a longer period of time unless your horse is a committed nibbler. Even horses on complete feeds due to loss of teeth can benefit with the offering of hay to munch on in between feedings.We can also try to decrease the stress level of horses, which may be easier said than done. After all, what is stressful for one individual may not be for another. Look for behavioral signs that let you know your horse needs more turnout time or more social contact. Try to reduce the stress of trailering by making sure your horse is trained to load easily and travel quietly. Make sure you are not a stressful driver either, taking corners too sharp or braking too suddenly!

There is also some limited research that suggests that the type of hay fed to horses may alter the incidence of ulcers. Horses on an alfalfa based diet relative to a grass hay diet appear to have lower incidence of ulcers. It is unknown whether this may be due to the protein or calcium content of the hay.

Alternative to NSAIDSMuch research in both humans and horses has been aimed at dietary interventions to prevent inflammation. The use of omega-3 fatty acids has been repeatedly shown to decrease inflammation in humans, and has had some promising use in horses as well. Addition of omega-3 fatty acids in the diet helps to block production of arachidonic acid, which is a producer of inflammatory thromboxanes, prostaglandins etc. Thus, use of adequate levels of omega-3 fatty acids in the diet may lessen the need for use of NSAIDS as therapy in the performance horse. In addition, polyunsaturated fatty acids may be able to help protect against gastric ulcers. In rats given dexamethasone to induce ulceration, a diet high in PUFA helped to suppress ulcers and maintained the normal lipid bilayer in the gastric mucosa. Furthermore, addition of omega 3 fatty acids may lower the stress experienced by horses as measured by cortisol production (a hormone related to stress). In mares provided with an omega-3 fatty acid source, cortisol levels were lower than controls following a period of stall confinement used to induce stress. Thus, while not proven to be a direct preventative of ulcer formation in horses, there is much promising data to indicate the effectiveness of omega 3 fatty acids as a dietary aid.

For information on premium stabilized ground flax supplements that are rich in natural Omega-3 to help maintain a shiny healthy coat, strong solid hooves, and top performance – and for clear and consise labels – for horses in all life stages – please click on Horse Health Products. Order online 24/7/365 – www.omegafields.com or call toll-free – 1-877-663-4203.

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Fun With Feed Math! Part 2: Rules to Feed By

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Written By Dr. Kris Hiney

Now that we have finished our discussion concerning our horses energy requirements, we are going to turn our attention to how best to deliver those calories to our horses. Over the next few months, we will discuss many confusing issues facing horse owners concerning the type, quantity, and quality of our feeds. As horse owners are barraged with information concerning grazing, metabolic syndrome, obesity and ulcers, it is sometimes easy to get lost in the conflicting information. So we are going to take it step by step, and do our best to understand these complex issues. Hopefully we all know that our duty as horse owners is to feed our horses a diet which maximizes their health, both physically and mentally. This month we will discuss strategies for feeding horses that will optimize not only the health of their digestive system, but keep them mentally sound as well. To understand how best to feed horses, we first need discuss the true nature of a horse prior to its domestication and modern management practices.

How the horse got started.

Horses certainly didn’t evolve on the lush pastures of Kentucky behind beautiful wooden fences. They were plains animals who drifted about continuously looking for sources of food. Horses successfully existed through times of rapid growth of grasses in the spring but also through the dormancy of fall and winter, times of drought etc. Compare that idea to horses who now have laminitis issues with grazing lush pastures! If we examine how horses naturally forage, they are selective grazers who seek out the most nutritious plants at particular stages of growth. Thus they moved continuously as they look for plants with greater palatability, and presumably more nutritional value to the horse. Feral horses will typically spend from one half to two-thirds of their day grazing, moving continuously as they graze. That means horses are meant to eat small amounts continuously and to travel extensively as they do so. Studies on grazing horses have shown that typically horses will cover 1-3 miles per day as they forage.

Grazing too much?The amount of time foraging is dependent upon the nutrient density of the pasture. The more sparse the vegetation, the more need for grazing time. Imagine wandering on the open plains searching for feed compared to grazing on well manicured pastures in Kentucky! On modern pastures that are managed well and improved with fertilization and seeding, it does not take as much time for the horse to meet its nutrient requirements. That is why we often see horses managed on pastures which are able to get fat, compared to feral horses. They are also confined to a greater extent, and thus may not be getting the amount of exercise a feral horse would receive. Additionally, many breeds of horses were originally selected from individuals who were more efficient at using feed. Think of our more docile breeds who have an easy going temperament. This personality type is often linked with the “thrifty” genotype. These guys (think ponies, Quarter Horses, Morgans, etc.) often have more problems with obesity and obesity related issues. In fact, this is such an important, and confusing, issue, we will address this problem specifically in an upcoming issue.

Let’s look on the inside!

From what we stated previously about the “normal” life for a horse, the horse’s digestive system is designed to deal with small amounts of food taken in continuously throughout the day. When we look at a horse’s digestive system, this easily makes sense. In comparison to our dogs, or cats, a horse’s stomach makes up a relatively small percentage of its entire tract. The stomach makes up about 10% of the entire tract, while the hind gut of the horse comprises 65% percent of the horse’s digestive capacity. While carnivores are considered to be opportunistic meal feeders (Eat as much as possible when you catch something because you never know when your next meal is coming!) horses are designed to eat small amounts (or continuous steady intake) throughout the day. The rate of passage, or how fast food moves out of the stomach, is fairly rapid. Two hours after eating, half of the solid particulate matter has passed out of the stomach, with ingesta reaching the hind gut within 5 hrs, while the stomach will be completely empty 10 hours post feeding.

So what does this mean for the horse? Interestingly, the horse’s ability to salivate is directly tied to mouth movements. In other words, they salivate when they chew. In other species, such as cattle, the salivary glands continuously produce saliva, of which a significant component is sodium bicarbonate. This continuous salivation buffers the rumen (or the foregut) of cattle and helps to prevent a drop in pH (or preventing an acidic environment). Compare this again to our meal feeders, (dogs, cats, and us), which salivate when we anticipate a meal. This helps the food slide down the esophagus with greater ease. Horses in the natural state have a relatively steady supply of saliva entering their stomach, with buffers included, as they graze throughout the day. However, compare the natural state to what happens when we manage horses in the typical box stall setting. Horses are provided with feed twice a day, with sometimes a prolonged period of time between their evening meal and the morning feeding. When the horse has not been provided with feed after 5-6 hours, the pH of their stomach begins to drop. This is why feeding strategies can directly impact our horse’s health. With a repeated drop in pH, the horse becomes susceptible to ulcers. Couple this with other risk factors for ulcer development and we can get a pretty unhappy horse. So our first rule of feeding horses is to provide enough forage to prevent the horse from being without anything to eat, ideally for less than six hours but at least avoiding a completely empty stomach 10 hrs post eating. Next month we will discuss ulcers in horses in depth.


From a riding perspective, we like it when horses salivate when they are ridden. This is typically equated with a horse being “soft in the face or jaw”. These horses are using their jaw and tongue and thus are not locked or stiff through the jaw resisting the rider. We often use bits that have a copper component which encourages salivation. Ever put a penny in your mouth? What happens? As horses salivate they will swallow, and this again helps to prevent a horse from stiffening through his jaw.

The stomach of the horse is not the only part of the digestive tract we need to be concerned with. As horses are designed to graze, their natural diet consists of longstem forages. While they possess the digestive capacity to utilize grains such as corn and oats, these would not make up a significant portion of the horses’ natural diet. However, we sometimes need to supply our horses with more energy dense sources of feeds when their energy requirements go up, such as moderate or intense exercise. We may also find ourselves sometimes short of hay due to prices, drought, supply shortages etc. Thus we may need to look at alternative feed sources than our typical baled hay. However, as horses are designed to ferment forages in their cecum and hind gut, it is important that we keep that fermentation functioning properly. To ensure this proper function, we need to feed horses at least 1 % of their body weight in forage per day. That means if your horse weighs 1200 lbs, it should never receive less than 12 lbs of hay or forage per day. Now if you actually weigh that out, you would see that really isn’t that much at all. Ideally, the horse should receive closer to 2% of their body weight in hay per day. So double that 12 lbs to 24 and you will be much closer to what the horse would naturally consume. On their own, horses will consume about 2-3% of their body weight per day. How we provide that amount, or if we provide that amount of feed, is up to us.

For horses that have high energy requirements, it may be necessary to provide them with extra concentrate. However, large meals of concentrates may not be great for gut health. If the rate of concentrate intake exceeds that of the horse’s ability to digest it in the small intestine, it escapes to the hindgut of the horse. Here, there are types of bacteria that will thrive on this meal of simple carbohydrates. Unfortunately, this carbohydrate fermenting bacteria will produce more acidic by products. The lowering of pH in the hindgut can set off a chain of unhealthy events, including laminitis, colic, diarrhea etc. Thus, horses should never be fed concentrate meals (the grain portion) in levels of over 0.5 to 0.6% of their body weight at one time. Beyond this point, we exceed the capacity of the horse’s small intestine to digest and absorb the meal. For our 1200 lb horse, that means that his grain meal should never be over 6-7 lbs. If the horse truly requires that much grain (12-14 lbs per day), the best solution would be to split the concentrate into multiple, smaller meals.

Fun With Feed Math! Part 1: Demystifying The Label

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Written By Dr. Kris Hiney

In our previous series we discussed the energy needs of horses, how they are calculated, how they differ between classes or types of horses, and how your feeding strategies should reflect the energy needs of the horse. For this series, we are going to switch gears a little, and focus on understanding commercial feed tags. In today’s equine feed market, there are an overwhelming number of feeds and types of feeds available to select for your horse. It certainly can be bit confusing at times. Our goal is to clear up some of the confusion and allow you to make the best choices based on your horse’s needs.

Types of feeds available.Typically, concentrates (what most horse owners refer to as grain or feed) are added to the equine diet to supply additional energy that cannot be met by hay consumption, or to supply additional protein. We will consider anything not in the classification of forage or roughage to fall into the “horse feed” category. When shopping for horse feed, you should know there are different classifications of feeds available: textured feeds, processed feeds, complete feeds, and supplements.
Textured feeds.

Textured feeds are those we typically think of as sweet feeds. They contain whole grains such as corn, oats, soybeans etc. that have been processed so that the horse can digest them more easily. Typically the grains are cracked, crushed, crimped or rolled which breaks up the outer layer of the kernel to allow the horse’s digestive enzymes easier access to the internal contents of the seed. The term “sweet feed” originates with the practice of adding molasses to the feed to enhance the flavor of the feed, suppress the dustiness of the feed, and to bind together additional ingredients. As most feeds are typically fortified with vitamins and minerals vital to the horse, it is important than these ingredients do not settle out of the feed and remain uneaten. The molasses essentially helps to prevent that from happening. Plus, most horses just plain love molasses!

Processed feeds.The second types of feed commonly encountered by the horse owner are the processed feeds. Rather than being able to indentify individual grains, these feeds are either pelleted or extruded. Pelleting essentially eliminates the concern of the fine particles (such as the vitamins and minerals) from being sorted out and thus ensures that the horse is receiving all nutrients intended by the feed manufacturer. Extruded feeds are produced under pressure and heat to create a lighter, less dense product which would more closely resemble dog food. As extruded feeds take longer for your horse to chew, there are some advantages to feeding these if your horse likes to rapidly ingest its feed. Further, prolonging chew time has some real advantages for your horse’s health (which we will discuss in the coming months). While both pelleted and extruded feeds have some advantages for feeding, realize the feed company has more processing involved, thus these products will cost more.
Complete feeds.Complete feeds are those that are intended to potentially serve as the horse’s only source of feed, and may serve to replace the forage component of the feed. These feeds have a fiber source added to the more traditional cereal grains, such as chopped hay, beet pulp or other fiber sources. While they serve the same purpose of maintaining the gut health of the horse as feeding hay, your horse may not consider it the same! The amount of time the horse spends eating will be less if only these feeds are fed, with no long stem forage. Ideally for the normal healthy horse, we recommend feeding 2% of their body weight in hay per day. (More on that again soon). So who are they appropriate for? For one, the senior horses who have poor teeth. It is vital that these horses are still consuming roughage, albeit in a different form than from their younger years. Older horses may not be able to properly chew hay, but they still have the desire to forage. Allowing them a source of hay to pick through is a great way to keep the old guys happy. Complete feeds are also quite handy if your forage supply is questionable, either from lack of supply or quality. As hay making is quite dependent on the weather, there certainly may be times where it becomes necessary to feed complete feeds to horses. They may also make a handy way to travel with your horse, as they are less bulky to handle and transport than hay bales.

Omega Horseshine Bag

The final category of horse feeds available fall into the category of supplements. These feeds are designed to supply protein, specific amino acids, essential fatty acids, vitamins or minerals to the horse which may be missing from its diet. While a properly fortified textured, pelleted/extruded, or complete feed may eliminate the need for supplements, many people seek supplements to optimize the diet of their horse. Omega Horsehine® and Omega Grande® would both be examples of supplements. They are fed in amounts less than that of traditional horse feed, and are formulated to supply key essential fatty acids, vitamins and minerals. Often times horses can meet their energy needs solely from forage alone, and many supplements are designed to meet the shortfall in specific nutrients that the forage may lack. Thus some specific supplements may eliminate the need to increase the grain component of the diet and provide calories the horse doesn’t need.


The feed or supplement you select must always be based first from the type of forage or roughage your horse is consuming! This is the bulk of what your horse consumes and feeds should be selected that complement your hay. For example, if you are feeding your horse high quality alfalfa hay which is high in protein, you do not need a high protein concentrate! Always consider your hay selection first!

What does a feed tag have to tell you?First, we need to discuss what information you will always find on a feed tag. On every feed label, both the product name and brand name must be included, so that the feed is identifiable. It will also include what the product is intended for, such as the type of horse including activity level, age, and reproductive state. This will provide you with an immediate guide to determine if the feed is appropriate for your horse. If you have a young, growing horse, you should look for a feed designed to meet the increased nutrient demands for growth.
Guaranteed Analysis.

Omega Nibblers Guaranteed Analysis

The second key piece of information on a feed tag is the guaranteed analysis. The following must always be included by the feed company on every product it sells: the minimum amount of crude protein, the minimum amount of crude fat, the maximum amount of crude fiber, both the minimum and maximum amount of calcium and the minimum amount of phosphorous. All of these will be listed in a percentage basis. Other nutrients will be listed in parts per million or ppm. For equine feeds, copper, zinc and selenium will all be included on the feed tag in these units. Finally, the amount of Vitamin A will be listed in International Units/lb or IU/lb (if needed). Many times the feed companies will include much more information, especially if the feed is designed for specific types of horses.


Let’s look at Omega Horseshine’s feed tag information- as it appears on the new 20 lb bag. The values highlighted in red are those that Omega Fields is required by the Association of American Feed Control Officials (AAFCO) to provide on their label. Those in black are not required, but may be of special interest to those selecting Omega Horseshine®.

Ingredient list.Third, after the guaranteed analysis, the feed company must then include a list of ingredients used to make the feed. The ingredients will be listed in the order of the ingredient included at the largest quantity to the ingredient included at the smallest level. Manufacturers may list specific feeds (such as corn or oats) or may use the term grain products. Grain products indicate some sort of processing method has occurred such as flaking, grinding etc. You may also see ingredients listed such as plant protein products. These are collective terms for an ingredient class. For example, cottonseed meal, linseed meal, soybean meal and yeast could all be included under the term plant protein product. The company is then able to change ingredients, usually dependent on market prices and availability, without changing the feed label. This allows the company some flexibility in the manufacturing process as to which ingredients may be selected, provided it does not change the guaranteed analysis of nutrient content! Other examples of collective feed terms are animal protein products (fish meal, meat meal, bone meal, skimmed milk, dried whey etc.), grain products (barley, corn, oats, wheat, etc.), processed grain products (brewers dried grains, wheat millings, distillers dried grains etc.) or roughage products (barley hulls, beet pulp, rice hulls etc.)In looking at our feed tag for Omega Horseshine® we can see that the three main ingredients are the flaxseed, yeast and ground oats. After these three products, the next ingredients listed are the minerals followed by vitamins, which is reflective of the amount of these items required in the equine diet.

Omega Horseshine label
Other information.Finally, the feed company will usually provide other information on their feed tag, such as feeding guidelines. This may include how much of the feed to provide, recommendations on the amount of forage to be fed or other such information. Providing the feed in the amount recommended by the feed company allows the feed to function as the manufactures designed it. For example, if one fed Omega Horseshine at only 1/4 cup per day, the horse would not be receiving the amount of Omega 3, minerals, and vitamins the feed was designed to provide in a daily ration. Conversely, over-feeding a feed can also be detrimental, as you may then be providing excess nutrients to your horse.The next article in this series will look at using feed tags according to horse’s actual nutrient requirements. This will involve a little bit of math, so get your calculators ready!

Feeding Forage, Part 2: Selecting Forage

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Written By Dr. Kris Hiney

Last month we discussed how much hay you should actually tuck away before winter. You don’t want to run out before that first cutting rolls around in June! But what about the quality of that hay? This month we will talk about what to look for in a quality hay; what things you don’t have to be so strict about in terms of quality, and what makes the most economical sense.

CuttingsMany people prefer to use only one certain cutting of hay, but that largely is irrelevant provided the hay is overall of good quality. Many choose to avoid first cutting hay, but it is certainly acceptable to feed horses. One of the difficulties of first crop hay may be a larger weed content, as these plants may grow more readily at the beginning of the growing season. However, if there are little to no weeds in the hay field, this may make little difference. It is true that first crop hay may be more difficult to put up due to weather conditions. Typically it rains more at the beginning of the growing season, so there is more chance that the hay will be rained on. Certainly rain can lower the nutrition value of the hay from 40-50%. However, careful inspection of the hay will allow you to determine if your hay has been rained upon. Hay that is grown in the hottest part of the months may result in more stems and less leaves as the plant grows rapidly. This can also lower the nutritional value of the hay. Later cuttings when it is cooler may have more leaves, less weeds, and perhaps less chance of being rained upon (depending on the whims of the weather). However, your best guide is to simply inspect the hay for quality, rather than automatically simply paying more for later cuttings of hay.

One of the first criteria in selecting hay is to determine how old the plant actually was when it was harvested. The older the plant is (whether it is a legume or a grass) the more fiber content is present. Translation – the less digestible it actually will be by your horse, and the lower the energy value of the hay, and the more hay you will “waste”. Now bear in mind this may not necessarily be a bad thing, especially if you have mature horses who are easy keepers. Previously we had stated that your horses ideally eat 2% of their body weight in hay per day. But if you are feeding at that level and your horse is fat, one viable option in lowering their calorie intake is to lower the energy density of their hay by choosing more mature hays. If you want to get the most bang for your buck, you would want to select younger hays. For grass hays, you want to examine the plants for the presence of seed heads. This definitely indicates a mature plant and one that will have more fiber and less relative feed value. Seed heads that are just beginning to show through the sheath are acceptable, but if the entire seed head is visible, the plant is very mature. Also look for a color change in grass hays. As the plant matures, they change from a bright green appearance to a more dusky grey. For legumes, look for flowers. For example, alfalfa develops purple flowers with an advanced vegetative state. While that field of pretty purple might be nice to drive by and look at, it means less nutrition for your horse!


The leaves of the plant contain the most nutritional value for the horse, so look for hays with greater leaf content. In grass hays, the maturity of the plant will definitely influence leaf content, as you will get more proportional stem as the plant matures. The same is true for legumes, which will get proportionally more stemmy with advancing maturity. The handling of the hay will also influence the overall leafiness. If fields have to be raked excessively (usually to aid with drying after rain), more leaf loss will occur. If the hay was allowed to dry excessively (below 12% prior to baling and storing) leaf shatter may occur resulting in a significant loss of nutrient content. Legumes are much more prone to leaf loss as the leaves are held much less firmly to the plant than in grass hays. Even handling of the hay post storing, such as transport, feeding etc. can result in great leaf loss in legume hays.

TextureWhen examining hays, it is important to actually get your hands on the hay. Horses prefer to eat hay that is softer and more pliable. This does directly relate to nutritive value, as tougher, stemmier hay will be higher in fiber content. A good test is to grasp several pieces of hay together and twist them. If the stems break and shatter, the less acceptable they will be by the horse. This can also indicate the hay was dried too much before baling.
ColorIdeally good hay has a bright green color. This not only reflects when the hay was harvested (especially for grass hays) but also how long the hay has been stored, if it was stored properly or if it was rained upon. Hay that has been exposed to sunlight will be faded or bleached to a yellowish appearance. Many vitamins are light sensitive, so expose to sun will decrease the nutritive content of the hay. However, don’t judge a bale too harshly by its cover. Open the bale up, if it is still green inside, it will still be a quality hay for the horse. Hay that has a grayish cast or is darker than normal may be moldy or may have been rained on. Rain will make hay have a more discolored appearance and again indicates a lower quality hay.
Free from…

Here is where you really need to pay attention to your hay. Inspect the hay for the presence of unwanted items. Weeds can not only lower the acceptability of the hay and the nutritional content, but can be seriously detrimental to your horse. Many weeds are toxic to horses or can cause physical damage through ingesting sharp barbs or nettles. It is generally not worth the risk to feed weedy hay, unless you are an expert at species identification! Also look for debris or trash. Normal hay fields don’t contain twine, pop cans, beer bottles etc. This may mean your hay actually came from a ditch or roadway. All of these can cause damage to your horse. While the occasional snake or mouse might be no problem (hey it happens), be especially vigilant for bugs, especially in alfalfa hay. Blister beetles are highly toxic to horses and ingestion of just a few can cause death. Last but not least, look for mold. You may find dark discolored areas, or patches of white fuzzy mold. Moldy hay should never be fed to horses. One easy test is to just smell your hay. It should have a pleasant, fragrant smell. A musty smell indicates mold. Break the hay open and slap it. If fine dust rises into the air, avoid it as well. Commonly hay that has been baled to wet (over 20% moisture) will mold in the barn. If you happen to have the fun job of individually unloading small square bales of hay, toss aside any that feel excessively heavy to you. They are probably wet, and you don’t want to store those in your barn.

Remember, any type of grass or legume hay can be good hay for your horse (assuming they are species horses eat), provided it is good quality. Don’t pay a premium value for your hay unless you have a chance to inspect it yourself. Don’t be afraid to turn away substandard hay. It is in the best interest of your horse.