Are Modern Equine Diet Recommendations Failing Horses? (Part 1)

January 20, 2024

By Sarah Griffiths, DCH

This week’s reflection is the result of some extensive research I’ve been working on to accurately explain the origin of the equine digestive system, why they evolved cecal (hindgut) fermentation and what horses are really designed to eat. After several months of digging into the science on foraging habits of feral horses, archaeological findings of ancient horse ancestors and the dietary causes of modern equine disease, I’ve been able to better understand how to feed horses accurately, to support them instead of hindering them.

There are several diet-related illnesses that are plaguing modern horses and it is not being addressed at the source in conventional practice. Modern horse diets consist of very few forage options, highly processed feeds, inappropriate (and arguably toxic) ingredients, synthetic vitamin and mineral supplements and very little diversity in fibre. Horses are developing diseases in direct relation to the fact that they are being fed in ways that cause major compensations in their genetically-evolved physiology, especially in the digestive and metabolic systems. We need to talk about this honestly and find solutions.

Colic, Gastric Ulcers and Equine Metabolic Syndrome

Horses are extremely resilient when they are cared for correctly. They can withstand extreme environments and survive on an incredible range of plants in nature when they need to. So why are there so many serious and life-threatening digestive and metabolic diseases affecting modern horses? I compiled the current equine health statistics from the National Health Institute and was very disturbed to find:

  • Colic remains the number one cause of death in domestic horses
  • Ulcers are rampant at a staggering rate of 60-90% of modern horses
  • Equine metabolic syndrome (EMS) and obesity affects 24-51% of all horses and accounts for 75% of laminitis cases.

Does this sound acceptable to you?

Why are Modern Horses So Sick?

Given the above statistics and the nature of the body systems involved, diet seems like a logical place to look. Most horses are living on one type of hay forage – what I now refer to as a “mono-forage diet.” And, despite all of the “scientifically balanced and complete” feeds I have assessed for clients, I haven’t seen much in the way of processed feed that I’d recommend. Highly processed feed is just as detrimental to horses as it is to people. My mission is to make this as obvious and understandable as possible. My ongoing investigation into the National Research Council’s current research and recommendations for feeding horses in, tandem with exploring archeological findings and equine disease research, has irreversibly changed my view of what it means to provide healthy equine nutrition. I’ve come to the conclusion that there is a LOT of work to do. If I’m honest, it’s a bit of a mess….

What is the National Research Council?

The National Research Council (NRC) is a board of scientific researchers that continually reviews equine nutrition research and creates equine dietary requirement recommendations for veterinarians, and feed companies to follow when formulating diets for horses. There are some huge drawbacks to solely using these guidelines to feed horses:

  • Recommendations from the NRC are based on the minimum nutrient levels needed to avoid nutritional deficiency. Providing the lowest possible amount of a nutrient needed for survival is not the same as providing nutritional levels that help horses thrive.
  • The NRC still admits a plethora of unknowns when it comes to equine nutrition when it comes to what levels of certain amino acids, vitamins and minerals are needed
  • The NRC allows for completely inappropriate and arguably damaging ingredients to be used in equine feed formulations including wheat, soy, corn, canola and cotton, grain by-products and animal proteins and fats such as fish meal and fish oil
  • The NRC suggests that macronutrients (fat and carbohydrate) can be interchangeably used to provide energy based on their relative caloric values. This is simply not true – if we look to science.

By using the NRC as our only reference guide to feed horses, we are missing some huge chunks of important information about how horses thrive in nature.

Zooming Out: Understanding the Bigger Picture of Equine Nutrition

NRC data and recommendations can be used as a starting point but it is not the bible of horse nutrition, as some professionals might believe. We can understand more about the discrepancies in modern equine feeding programs by studying the following:

  • How do wild horses feed themselves? There is field research available to accurately depict the native diet of horses. These studies offer valuable information you won’t find in conventional textbooks. What they select from their environment is drastically different than conventional/industrialized horse diets.
  • How has the equine digestive system evolved over the past 55 million years and why? Horses evolved cecal (hindgut) fermentation for very specific reasons: mainly to adjust to the changing climate and a significant increase in complex carbohydrate (fiber) from plants in the environment. More difficult-to-digest fiber (cellulose) required fermentation to be used as a digestive aid and vital survival tool. This highly evolved physiology is a key factor to understanding how to better serve horses with nutrition. Horses are specialized in how they obtain energy and nutrition from food.
  • How can we reverse engineer the causes of diet-related gut and metabolic diseases? By compiling peer-reviewed scientific research about how these diseases are caused, we add another piece to the puzzle. There is a large body of research on the dietary contributing factors to equine gastric ulcers, colic and equine metabolic disease. Taking the time to look at these disease processes in reverse allows us to see what foods (feeds) really aren’t working for horses.

We’ll break the subjects down into their own articles in the weeks ahead. By exploring these truths, we can zoom out and see the bigger picture. Relying solely on the NRC is not serving horses. We are failing them and we need more tools. This requires honesty and curious exploration. It’s time for change. I hope to be a part of that change and I hope you will be too.

Stay tuned for my next equine blog: The Ancestral Equine Diet: Exploring the Native Diet of Horses