Is your horse getting what she needs in her current diet? Does she have health concerns that could be improved through feeding practices?

If you own or care for horses, chances are you have asked yourself these questions at some point. You may have even sought out the services of an equine nutritionist to help you formulate a balanced diet for your horse.

Equine nutritionists are university-educated professionals with expertise in the feeding and management of horses. Nutritionists are trained in both practical on-farm feeding situations and the science of equine physiology and metabolism.

Whether you are designing a diet for the first time, an experienced barn manager, a competitive athlete, or a concerned horse owner caring for a horse with health concerns, this article is for you.

At Mad Barn, our nutritionists formulate thousands of diets every year for free for horse owners across North America. You can submit your horse’s information online for a free diet analysis or book a nutrition consultation by phone.

Equine Nutritionist Qualifications

The nutritionists at Mad Barn have dedicated their lives to learning how to best feed horses. Our training begins with a four-year bachelor’s degree in nutrition, animal science, or another field related to equine nutrition.

During a bachelor’s degree, we take many academic and practical courses to ensure we are well-versed in animal health, nutrition, metabolism, and management.

Following a bachelor’s degree, a nutritionist will typically complete a one- or two-year master’s degree in animal nutrition. During a master’s degree, our primary focus shifts from classroom learning to research experience.

Masters students do take advanced courses to gain a deeper understanding of nutrition and the principles of diet formulation, but we also conduct animal trials. This teaches us to execute research studies and interpret results from published literature.

At the end of a master’s degree, nutritionists complete and publish a thesis outlining everything we have learned from our research.

After a master’s degree, some nutritionists will go on to complete a doctorate degree (Ph.D.) in nutrition or a related field, which can take anywhere from 3 to 5 years or more.

During a Ph.D., we still take some courses to deepen our understanding of nutrition principles, but the main focus is research. Ph.D. candidates also typically assist with teaching undergraduate courses in equine or animal science.

Ph.D. students learn how to design nutrition experiments, become proficient in executing research, and publish our findings to drive advancements in nutrition.

Having a strong theoretical grasp of nutrition, digestion, physiology and metabolism is what allows qualified nutritionists to translate experimental data into real-world feeding solutions.

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Working with an Equine Nutritionist

When you work with a nutritionist, we look at many different factors related to your horse’s current feeding program, physiological status, health history, activity level, housing situation, and more.

For example, when you submit a diet evaluation to Mad Barn, we collect a lot of information such as your horse’s age, breeding status, exercise level, feeding situation, and geographic area.

We use this information and your comments about your horse’s health to understand how her current diet compares to her predicted nutrient requirements. From there, we can formulate a recommended diet to better meet her needs and ensure balanced ratios of all nutrients.

Here’s a look at how some of the following details impact our evaluation of your horse’s nutritional requirements:

Physiological Status

Weight and Age

Nutritional requirements are calculated based on your horse’s current weight for mature horses and expected mature weight for growing horses. Horses that are five years old or younger are considered growing, and their requirements will be adjusted accordingly.

There is no difference in the requirements for adult and senior horses. However, if you have an aged horse with special needs, we may recommend supplementing extra energy, protein or other nutrients to help improve or maintain their condition.

Growth

Horses are considered growing for nutritional purposes until they are five years old, which is why we ask for your horse’s date of birth.

Growing horses have higher energy, protein, vitamin and mineral requirements to support the development of their skeleton, muscles, and other tissues. [1]

Protein and energy requirements are calculated based on their mature weight with higher intake to support age-specific development. Vitamin and mineral requirements are also based on expected mature body weight.

It’s important to ensure you are meeting the nutrient requirements of a growing horse, but also important not to significantly exceed their requirements. Feeding a young horse excess protein or energy can increase the risk of developmental orthopedic diseases.

Exercise

The level and frequency of exercise your horse gets impacts her energy and protein requirements and also influences vitamin, mineral, and electrolyte requirements.

The way we classify exercise load for nutritional purposes is not always intuitive. [1] The workload has a big impact on how we calculate requirements, so it’s important that we get it right.

Horses at maintenance are not exercising or working. These horses might be turned out in a pasture, but are not actively being trained or ridden.

Horses in light exercise might train for 1-3 hours per week, mostly at a walk and trot. Recreational riding horses, some horses at the beginning of training programs, and horses that show occasionally are usually in light work.

Horses in moderate exercise train more frequently or for longer durations. They typically work about 3-5 hours weekly, mostly at a walk and trot. School horses, horses at the beginning of more intense training, and show horses that frequently show in minimally strenuous events (i.e. pleasure classes) are usually in moderate exercise.

Horses in heavy exercise train more intensely. They might work 4-5 hours per week, mostly at a trot and canter or doing skill work like jumping. Working ranch horses, show horses participating in frequent, strenuous events, and barrel racing horses are often in heavy exercise.

Horses in very heavy exercise may have variable training times and intensities but a very heavy workload overall. These horses might participate in activities ranging from 1 hour per week of speed work to 6-12 hours per week of lower intensity work. Race horses and elite 3-day eventing horses are typically in very heavy exercise.

Pregnancy and Lactation

To support fetal and foal development, pregnant and lactating mares require extra energy, protein, vitamin and mineral support. [1]

Their requirements are based on the stage of pregnancy or lactation they are in. Nutritional needs are highest during later stages of pregnancy and early stages of lactation.

This is why we ask how many months pregnant or lactating they are. Pregnant and lactating mares must be managed closely to ensure their diet is balanced. Imbalanced nutrition can impact their health and the health of their developing babies.

Breed

Your horse’s breed does not impact how we calculate her nutritional requirements. However, it can still be helpful information to consider in our evaluations.

For example, if you are unsure of your horse’s current weight, we might use the average mature weight for their breed to make an estimate.

Additionally, some breeds are predisposed to health issues that might impact their nutritional needs.

How We Calculate Your Horse’s Nutrient Intake

Our open-access feed formulation tool makes it easy to calculate your horse’s estimated nutrient intake by looking at their current feeding program.

Our feed bank database includes nutrition composition data for over 3,000 forages, feeds and supplements that are commonly fed to horses.

Simply tell us what you are feeding your horse using our diet evaluation form and our nutritionists will put together a report showing their current intake levels for key nutrients.

Hay and Pasture

Forage Intake

Measuring how much hay and pasture your horse eats can be difficult, but we use a few key pieces of information to make estimates.

Most horses will willingly consume about 2% of their body weight in dry matter if they are given free choice access to forage. [1] This estimate may increase for horses in heavier workloads or during some stages of pregnancy and lactation. [1]

When we calculate your horse’s forage intake, we assume that they are maximizing forage intake if they are given free choice access.

We base our pasture intake estimates on how long your horse is allowed to graze daily. As a general rule, horses turned out on pasture eat about 1-2 lb (0.45-0.9 kg) of pasture dry matter per hour.

An average horse on pasture 24 hours a day will graze for about 16 hours, meaning they can consume 16-32 lb (7-15 kg) of pasture dry matter daily, representing roughly 2% of bodyweight. [21]

We will also consider other factors, such as their dental health and whether or not they wear a grazing muzzle.

After estimating how much pasture your horse is getting, we assume that they make up the rest of their predicted dry matter consumption with hay and other feeds.

Hay Analysis

To determine the exact nutrient content of your hay and pasture, we recommend that you conduct a forage analysis.

A forage analysis will tell you how much energy, protein, fibre and sugar and provide values for other important nutrients. We look at the results of your forage analysis as the starting point for building a balanced diet.

If you do not have an analysis, we will base our calculations on the average content of the forage type you are feeding.

Our estimates are also based on regional soil and forage mineral concentrations. Levels of minerals such as selenium, sodium, and manganese vary in different geographic regions. Accounting for those differences helps us give you the most accurate information possible.

Concentrates and Supplements

Our feed bank also contains nutrition composition information for many commonly fed concentrate grains and supplements.

We look at how much of these products you are feeding as well as manufacturer guidelines for any commercial supplements to build a balanced diet.

If you are feeding a product that is not currently in our database, specify the product and how much they are getting in the comments section of your submission. We will obtain a guaranteed analysis from the manufacturer to formulate your diet.

Our Diet Evaluation Process

After determining your horse’s nutrient requirements and current intake, we will evaluate their diet to ensure that their requirements are met, and their intake is balanced.

How you feed your horse is as important as what you feed your horse. We may suggest changes to your horse’s management to help address their behavioural needs and better support gut health.

We recommend following a forage-first diet and choosing hay that matches their energy requirements.

This will fulfill your horse’s need to express foraging behaviours for up to 16 hours per day and ensure that their stomach does not remain empty for long periods, helping to reduce the risk of gastric ulcers.

Here are some of the other important aspects of the equine diet that we look at during our evaluations.

Energy and Protein

Your horse’s energy and protein intake should be closely matched to her requirements. In 2021, 85% of the diets we evaluated were over-supplying energy and 98% of diets were over-supplying protein.

Excess energy intake can lead to unwanted weight gain, and excessive protein intake can lead to increased ammonia excretion. [2] This puts strain on your horse’s kidneys and increases the cost per day of your horse’s diet.

However, it’s also important to ensure you are feeding enough energy and protein. Energy deficiency can lead to weight loss and protein deficiency can lead to loss of muscle mass and other health issues.

In addition to total protein intake, it’s also important to ensure that your horse is receiving an adequate supply of rate limiting amino acids.

Minerals

Minerals are important nutrients that play critical roles in enzyme reactions, energy metabolism, and electrolyte balance.

If your horse is not getting adequate amounts of key macrominerals or trace minerals, they may experience bone, joint, muscle, hoof, skin, coat, respiratory, circulatory, metabolic or even neurological issues.

Nutritionists look at the concentration of individual minerals in the overall diet to ensure that there are no deficiencies or excesses. We also look at the ratios of certain minerals to keep these numbers in balance.

Excess intake of some minerals can cause secondary deficiencies by interfering with the absorption of other minerals. This can cause a deficiency even if your horse is receiving adequate intake.

For example, imbalanced calcium and phosphorus intake or excessive iron intake can lead to secondary deficiencies.

Based on a recent review, 99% of equine diets are over-supplying iron and 49% of the diets we evaluate are under-supplying selenium.

We also look at the form of minerals used in commercial feed products and supplements. Many feeds are formulated with inorganic trace minerals, but research shows that organic minerals are better absorbed and utilized in the horse’s body. Minerals in organic forms are more effective for supporting hoof health, immune function, coat quality and many other processes. [22][23][24]

Vitamins

Vitamin intake should be adequate to support your horse’s current physiological state. In 2021, 57% of the diets we evaluated were under-supplying vitamin E.

In addition to ensuring that your horse is meeting her vitamin requirements, a nutritionist will ensure that their intake is not exceeding requirements too much. It is especially important to not feed fat soluble vitamins in excessive amounts as they can be toxic at very high levels.

Electrolytes

Electrolytes are minerals that are involved in muscle contraction, nerve signal transmission and fluid balance.

These minerals need to be supplied in adequate levels to encourage hydration and prevent conditions such as thumps.

Horses lose electrolytes in their sweat and urine. If your horse is in a hot climate or is exercising, they will need higher levels of electrolytes in their diet to replenish those lose in sweat.

In our recent analysis of over 6,500 equine diets, 71% of diets we evaluated were under-supplying sodium. To correct this, we typically recommend adding salt from a feed store or grocery store to your horse’s daily ration and providing loose free-choice salt at all times.

NSC

Non-structural carbohydrates (NSC) are rapidly digested carbohydrates in the horse’s diet, including sugars and starches.

For most horses, high levels of NSCs are not necessary, and can lead to digestive, metabolic, and other health complications.

High levels of NSCs are found in grain-based complete feeds and sweet feeds that contain molasses. Some forages may be high in NSCs and should be soaked to lower the carbohydrate content.

Individualized Nutrition

In addition to ensuring that your horse’s diet is well-balanced, an equine nutritionist also considers any individual health concerns or performance goals that you have for your horse.

A well-balanced diet and specific nutritional interventions can support horses with certain health concerns or help to improve performance in competition horses.

Below are some common goals and health concerns that horse owners mention during our diet evaluation process and how we address them through nutrition.

Joint Health

In 2021, 38% of the horses that we worked with had joint concerns reported by their owners.

To support joint health, ensure that your horse’s core vitamin and mineral needs are met. After addressing any dietary imbalances, we recommend adding W-3 oil and MSM to their diet.

W-3 oil is an essential fatty acid supplement that contains the omega-3 DHA. DHA has been shown to lower inflammatory markers in the joints of arthritic horses and to have a protective effect in healthy joints. [3][4][5][6].

Methylsulfonylmethane (MSM) powder is a readily available form of sulphur that can support healthy connective tissue such as joint cartilage, tendons, and ligaments. [7][8]

Hoof Concerns

38% of the horse owners that our nutritionists worked indicated hoof concerns in their horses.

Balanced vitamin, mineral and amino acid intake is essential for hoof health. In particular, horses need 20 mg per day of the water-soluble vitamin biotin to ensure adequate keratin formation. [9][10][11][12][13]

The minerals zinc, copper and selenium are also required to support hoof growth. [14] If your horse has hoof issues, provide a complete balanced vitamin-mineral supplement to correct common deficiencies and help grow out strong, robust hooves.

Topline Muscle

35% of horse owners reported to us that they would like help with improving their horse’s topline.

Many horses experience a loss in topline muscle mass as they age. Muscle loss occurs when muscle protein degradation happens more rapidly than protein synthesis.

To encourage protein synthesis, feed your horse a well-balanced diet that supplies the limiting amino acids – lysine, methionine and threonine – in sufficient amounts.

If your horse is on a low quality hay or not getting enough protein, it may be helpful to supplement additional amino acids in their diet. [15]

Additionally, exercises such as pole or hill work may stimulate topline development.

Digestion Concerns

30% of the horses that we conducted diet evaluations for had gut health concerns listed by their owners.

Digestive issues can manifest as colic, diarrhea, free fecal water, ulcers, hindgut acidosis, secondary nutrient deficiencies, weight loss, or a number of other issues.

Many gut problems can be managed by minimizing your horse’s stress, ensuring adequate forage consumption, promoting water intake, and reducing NSC intake. However, some horses may need additional digestive support.

Depending on your horse’s digestive issues, we may recommend a supplement to support stomach and hindgut health or to target hindgut health specifically.

Adding probiotics can be beneficial for supporting gut health, even when no digestive issues are apparent.

Weight Management

29% of the horses that our nutritionists formulated diets for had weight issues, meaning they were either overweight or underweight.

There are a number of interventions we recommend for easy keepers and overweight horses, depending on your specific management constraints.

Reducing pasture access, using a hay net, rationing or soaking your hay, turning out your horse with a grazing muzzle, and feeding chopped straw can decrease your horse’s energy intake. You can also exercise your horse more to increase their energy expenditure.

If your horse is underweight, increasing forage intake or adding alfalfa, beet pulp, flax, or oil can increase the energy density of the diet without adding unnecessary sugar and starch.

Calming

20% of the horse owners that consulted with us indicated their horses had calming concerns.

Horses may be hot or more reactive if they have vitamin or mineral imbalances, digestive issues, limited activity, or low forage accessibility. [1]

Boredom, social isolation, and a lack of freedom can also contribute to the development of stereotypic behaviours.

Ensure your horse has a balanced, forage-based diet with plenty of time to move around, friends to socialize with and an environment that supports their well-being. Consider enrichment activities to prevent boredom.

In some cases, we may explore calming supplements, such as the chasteberry herb, which may help to stabilize hormones and improve moodiness. [16][17]

Insulin Resistance

15% of the horses we formulate diets for have some form of metabolic concern that must be factored into their feeding plan.

Equine metabolic syndrome (EMS) involves insulin dysregulation and affects how horses digest, absorb and use sugars.

Management of horses with EMS should focus on:

  1. Increasing exercise level to combat weight gain and insulin resistance
  2. Decreasing energy intake to promote healthy body weight
  3. Reducing NSC intake by eliminating or reducing grains and added sugars in the diet
  4. Balancing vitamin and mineral intake using a nutritional supplement formulated specifically to support horses with metabolic issues

Respiratory Health

10% of the horses whose diets we analyzed last year had some form of respiratory concern that needed to be addressed.

You can support your horse’s respiratory health by providing a well-ventilated barn environment and soaking hay to reduce dust content.

For horses with respiratory concerns, we typically recommend feeding w-3 oil, as it contains high levels of the omega-3 fatty acid DHA. DHA has been shown to alleviate symptoms associated with recurrent airway obstruction (heaves) and inflammatory airway disease. [18]

Jiaogulan and spirulina are two natural products that may help minimize the coughing, headshaking, snorting, and sneezing often associated with poor respiratory health. [19][20]

Conclusion

Whether your horse is an easy keeper or struggling with a health concern, a balanced feeding program is key to maintaining their health.

Consulting with a qualified equine nutritionist will ensure there are no gaps in your horse’s diet and help you troubleshoot common nutrition-related problems.

You can submit your horse’s information online for a free diet evaluation from one of Mad Barn’s university-trained equine nutritionists. We are here to help!

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References

  1. National Research Council. Nutrient Requirements of Horses. The National Academies Press. 2007.
  2. Bott, RC. et al. Environmental Implications of Nitrogen Output on Horse Operations: A Review. J Equine Vet Sci. 2016.
  3. Woodward, AD. et al. Supplementation of dietary long-chain polyunsaturated omega-3 fatty acids high in docosahexaenoic acid (DHA) increases plasma DHA concentration and may increase trot stride lengths in horses. Equine Comp Exerc Physiol. 2007.
  4. Manhart, DR. et al. Markers of inflammation in arthritic horses fed omega-3 fatty acids. Prof Anim Sci. 2009.
  5. Caron, JP. et al. Omega-3 fatty acids and docosahexaenoic acid oxymetabolites modulate the inflammatory response of equine interleukin1 ?-stimulated equine synoviocytes. Prostaglandins Other Lipid Mediat. 2019.View Summary
  6. Vanderweerd, JM. et al. Systematic review of efficacy of nutraceuticals to alleviate clinical signs of osteoarthritis. J Vet Intern Med. 2012. View Summary
  7. Marañón, G. et al. The effect of methylsulphonylmethane supplementation on biomarkers of oxidative stress in sport horses following jumping exercise. Acta Vet Scand. 2008.
  8. Butawan, M. et al. Methylsulfonylmethane: Applications and safety of a novel dietary supplement. Nutrients. 2017.
  9. Comben, N. et al. Clinical observations on the response of equine hoof defects to dietary supplementation with biotin. Vet Rec. 1984. View Summary
  10. Buffa, Eugene et al. Effect of dietary biotin supplement on equine hoof horn growth rate and hardness. Equine Vet J. 1992. View Summary
  11. Geyer, H. and Schulze, J. The long-term influence of biotin supplementation on hoof horn quality in horses. Schweizer Archiv fur Tierheilkunde. 1993. View Summary
  12. Josseck, H. et al. Hoof horn abnormalities in Lipizzaner horses and the effect of dietary on macroscopic aspects of hoof horn quality. Equine Vet J. 1995.View Summary
  13. Reilly, J.D., et al. Effect of supplementary dietary biotin on hoof growth and hoof growth rate in ponies: a controlled trial. Equine Vet J. 2010.View Summary
  14. Mills, CF. Dietary interactions involving the trace elements. Annu Rev Nutr. 1985.
  15. Urschel, K.L. and Lawrence, L.M. Chapter 6: Amino acids and protein. Equine Applied and Clinical Nutrition. 2013.
  16. Nasri, S. et al. The effects of Vitex agnus castus extract and its interaction with dopaminergic system on LH and testosterone in male mice. Pak J Biol Sci. 2007.
  17. Ahangarpour, A. et al. Effects of Vitex agnus-castus fruit on sex hormones and antioxidant indices in a D-galactose-induced aging female mouse model. J Chin Med Assoc. 2016.
  18. Nogradi, N. et al. Omega-3 Fatty Acid Supplementation Provides an Additional Benefit to a Low-Dust Diet in the Management of Horses with Chronic Lower Airway Inflammatory Disease. J Vet Intern Med. 2015.View Summary
  19. Roughan, Grattan P. Spirulina: A source of dietary gamma-linolenic acid? J Sci Food Agri. 1989.
  20. Hinckley, KA et al. Nitric oxide donors as treatment for grass induced acute laminitis in ponies. Equine Vet J. 1996. View Summary
  21. Siciliano, P.D. Estimation of Pasture Dry Matter Intake and its Practical Application in Grazing Management for Horses. University of Minnesota. 2013.
  22. Kania, M. et al. Effect of diet on mechanical properties of horse’s hair. Acta Bioeng Biomech. 2009. View Summary
  23. Montgomery, J.B. et al. Effects of selenium source on measures of selenium status and immune function in horses. Can J Vet Res. 2012. View Summary
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