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.
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:
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.
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. 
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.
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.  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. 
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.
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
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.  This estimate may increase for horses in heavier workloads or during some stages of pregnancy and lactation. 
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. 
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.
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.  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 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 over