Does Your Horse Have A Nutritional Deficiency?

November 24, 2023

By Sarah Griffiths, DCH

Horses living in modern times are facing some hard health challenges. Equine nutrition is one of my favorite subjects and I’ve had the privilege over the past 20 years to spend time with a wide array of horses of all sizes, breeds and ages in a number of different environments. What I’ve observed is that horses are not getting everything they need with our modern management practices. The ethics around keeping horses is changing and I’m so happy to see this.

There are mixed reports on the top 5 chronic pathologies in horses but instead of looking at the surveys and veterinary reports, I followed the money and looked up what one of the most popular equine health insurance companies (Pet Plan) is reporting as the highest claimed health conditions they cover:

  1. Arthritis and Osteoarthritis
  2. Gastric Ulcers
  3. Colic
  4. Desmitis (Lameness/Ligament Inflammation)
  5. Laminitis / Metabolic Disorders

Each of these conditions have an obvious connection to nutrition. And that’s what we are going to dive into today!

The “Science” of Equine Nutrition

Unfortunately, the world of conventional veterinary nutrition has become more of a business model than what’s best for horses. No one actually knows what horses truly need to eat and are largely being managed with cured forage and the aid of synthetic supplements and feeds. The National Research Council who distributes the best educated guess on nutrient requirements for the equine species is extremely limited due to the lack of scientific research being done on equine nutrition. Research is heavily focused on studying how to feed them synthetically instead of based on what they actually need to eat eg. a wide variety of naturally occurring forage!

When we feed them based on theories about mimic requirements rather than what they naturally eat, we leave the unknown parts out. There are so many variables to nutrition and there is no way to synthetically re-produce that no matter how many scientific studies are done. That’s why I always refer back to studies on what wild horses eat rather than what humans say they should eat. I also rely on my observational skills in the field and watch what plants horses eat here in the Pacific Northwest.

Between modern management practices, poor understanding and execution of dietary needs and elevated stress levels on the sport and pleasure horse fronts, many modern horses are suffering unnecessarily with diseases that involve nutrient deficiency. And you can’t fix what you don’t know so let’s dive in to where things can go wrong and how to help your horses.

Recognizing Equine Nutritional Deficiencies

In my practice, I look at a lot of diagnostics and see some common deficiencies in horses. Let’s start practically with how to recognize the most common nutrient deficiencies, the causes and practical solutions to those issues.

1. Calcium 

Signs & conditions: Chronic injury, back pain/joint pain, neurological issues, bone spurs, string halt, metabolic disease

Systems most heavily affected: musculo-skeletal and neurological

Causes: Incorrect calcium/phosphorus ratio, excess starch and/or protein, confinement and drugs, esp. steroids.

Foods: Sugar-free beet pulp & alfalfa (organic only!), chia seed, leafy veg

Supplementation for severe cases: Calcium citrate (buffered) – 2000mg / day for 4 weeks, then 2 x weekly after that

Blood testing: Check blood every 3 months to ensure you are getting results

2. Selenium

Signs & Conditions: typing up, skin/hoof disease, hypothyroidism, insulin resistance, fatigue, heavy metal toxicity, liver disease

Systems most heavily affected: Musculoskeletal, immune, endocrine (thyroid & sugar met), liver tonic

Signs: dull coat, skin disease, sweet itch, immune dysfunction, hypothyroidism, insulin resistance, hoof growth issues (esp. cracks)

Causes: deficient diet, medications, excess dietary starch, heavy metal toxicity

Foods: Whole organic oats, grass and hay but sadly, soils are too deficient now

Supplement: organic selenomethionine – NOT synthetic which is toxic to the liver

Instructions: 1000-2000 mcg daily

Blood testing: Check blood every 6 weeks to ensure you are getting results. Do not over-supplement with selenium and be sure to check blood readings when you are supplementing. Start low and slow.

3. Magnesium

Signs and conditions: high anxiety, colic, muscle spasm, hard keepers, insulin resistance

deficient diet, gut damage, excess starch, stress/overtraining, medications

Systems most heavily affected: musculoskeletal, immune, endocrine, digestive

Foods: Grass/hay green leafy veg, seeds (esp. chia)

Supplement: Magnesium citrate (NOT magnesium oxide)

Instructions: 1500mg daily OR acute colic – 2000-3000 mg – have in the first aid kit

4. Vitamin B12

Signs & Conditions: anxiety, colic, muscle spasm, insulin resistance, gut disease, neurological disorder, anemia, fatigue, weakness (seniors), liver toxicity

Systems: digestive, endocrine, nervous systems

Causes: gut damage, ulcers, stress/cortisol, low stomach acid, microbiome imbalance!

Food: The microbiome! (keep reading), grass and hay, spirulina and seaweed, medicinal mushrooms (turkey tail, chaga, lion’s mane, shiitake, etc.)

Supplement: Methylcobalamine

Instructions: 6000-12000 mcg /day

Blood testing: every 3 months

5. Vitamin E

Signs and conditions: cataracts, arthritis, kidney/liver disease, neurological issues, senior horses, inflammatory diseases, eye issues, joint issues, aging

Systems most heavily affected: all body systems but often shows up neurologically

Causes: deficient diet, liver/kidney toxicity, neurological disease, aging

Foods: black oil sunflower seeds, green leaf veg, grass, pumpkin seeds, dried cranberry, grapeseed oil

Supplement: d-alpha tocopherol (natural version) liquid! Powder is not bioavailable.

Instructions: 1000-2000 IU daily and 3000-5000 IU prior and during competition or surgical/stressful evets

Blood testing: every 3 months until resolved. Reduce dosage as numbers fall into normal parameters.

6. Omega 3 Fats

Signs and conditions: chronic inflammation (anywhere in the body), ulcers, colic, joint-related inflammation and degeneration, kidney disease, skin disease, neurological disease

Systems most heavily affected: GI, urinary, nervous, immune

Causes: deficient diet, stress, liver/kidney toxicity, gut damage, inflammation

Foods: freshly ground flax, soaked chia seed, hemp

Supplement: plant-based oils (flax, hemp, chia, camelina, ahiflower) – please do not feed your horses fish oil. It is not only terrible for environmental sustainability but it’s also often rancid and completely inappropriate for horses. We will dive into omega 3’s further in the future.

Instructions: (rotation use of the follow in best!)

Soaked chia – ½ cup soaked seeds daily

Freshly ground flax – 1-2 cups daily

Hemp oil – 3-5 tbsp daily

Digestive Health Will Affect Nutrient Absorption

When a horse lives in a field, they are eating microbes from living soil all the time! This is the way they inoculate the gut with healthy microbes and keep the bad ones at bay. They can’t diversify the microbiome and support a healthy microbial community without this regular environmental integration process. When they can’t graze, beneficial microbes are essential via probiotics and prebiotic fibres. Most paddock situations mean that the soil is sterile and this paves the way for pathogenic microbial communities to take the lead. It also promotes parasite growth in the ground. I will write a blog specifically on parasite management in a future article.

Remember the most common equine diseases above?

Nutrients cannot be absorbed properly in a damaged gut or by a metabolically disturbed horse. Nutrient absorption is drastically altered/diminished by gut damage and by metabolic disease so it’s imperative to get on top of these as soon as possible. You can feed the best of everything but if the gut is not well or your horse is struggling with metabolic issues, nutrients  will have a difficult time making it into the cells.

Environment is just as important as diet when it comes to managing and preventing chronic disease. Use pre & probiotics, ensure some grazing time in areas with living dirt, increasing movement and diversifying the diet with healthy whole foods means you’re feeding the microbiome diverse proactively and this will result in production of a diverse number of metabolites – including folate, vitamin B12, short chain fatty acids and much more – essential for immune, metabolic, neurological, digestive function and beyond. The science being uncovered on these fronts is growing and will continue to expand. I will explore and report on each of these subjects on the blog so keep checking in!

Other Tips to Complete the Nutrition Puzzle:

  1. Blood Testing – Useful blood tests to help you figure out what needs adjusting include a mineral blood profile, vitamin B12, folate, vitamin E and selenium testing. Based on what you are seeing, you can choose which of these tests seem most appropriate to start with. You’ll want to use your first test as a baseline and then test every 6-12 weeks thereafter until you’re seeing the nutrient levels you want to see. See above for specifics on when to repeat blood testing for different nutrients.
  2. Hay Testing – Hay analysis is a crucial puzzle piece when it comes to solving nutritional deficiencies. If you don’t know what’s in your forage (eg. the largest part of your horse’s diet), then you’re hooped! So make sure you’re not just stabbing in the dark with supplements and get your hay tested so you can make educated additions and subtractions to your horse’s diet. Work with an equine nutritionist if you don’t feel confident analyzing results and adjusting the diet on your own. Look for my guide on reading hay analyses – out on the blog in the coming weeks!
  3. Always establish a long term plan when dealing with deficiencies – meaning that even when you’re supplementing, start integrating a healthier lifestyle with diet adjustments along the way so that you aren’t just using supplements to address the underlying cause. There are a million environmental, emotional, training and management factors that could be contributing to imbalances in your horse. We will explore these factors further in the future!

Nutrition is interconnected with almost all aspects of equine health and management so be sure you’re taking a good look at what your horse might be missing and make the changes they need to thrive. Happy feeding!