Nutrient Requirements of Horses
Why Are Feeding Guidelines So Important?
By Shelagh Niblock, PAS
You may have heard of the National Research Council (NRC) and the Nutrient Requirements of Horses - but what are they and why do they matter?
Have you ever wondered who determined the amount of protein a growing horse needs to fulfil its genetic potential? Or the amount of energy a performance horse needs to be successful?
What determines the amount of minerals and vitamins in the manufactured feeds we buy for our horses?
The go-to reference for ensuring that what we feed our horses meets their nutritional needs is called the Nutrient Requirements of Horses: Sixth Revised Edition, by the National Research Council of the National Academies. This guideline is part of an Animal Nutrition Series of guidelines published by the National Research Council, and the National Research Council is a part of The National Academy of Sciences.
But what does all this mean? It means that our horses are in safe hands when we feed them according to the guidelines established by these well-respected organizations.
Equine nutritionists and the manufacturers of quality horse feeds use the Nutrient Requirements of Horses, a document comprised of the best peer-reviewed scientific research, to establish all of their recommendations and formulations. Sometimes called the National Research Council (NRC), this reference guide is considered the equine nutritionist’s gold standard when it comes to making safe, effective nutritional recommendations. But what is the NRC, and why does it have a role in the way we feed our horses?
Many products make claims based on anecdotal evidence. For your horse’s sake, always look for claims supported by good science. Photo: iStock/Pavle Bugarski
National Research Council and the Committee on Nutrient Requirements of Horses
The Nutrient Requirements of Horses, Sixth Revised Edition was first initiated in 2004 by a committee of equine nutritional researchers. The Committee on the Nutrient Requirements of Horses is comprised of academics who, in most cases, have spent most of their professional lives conducting scientific research on all equids, including horses, ponies, donkeys, and mules. At that time, the committee utilized the earlier editions of the Nutrient Requirements of Horses, as a foundation to begin their compilation and evaluation of any new research in equine nutrition found in the scientific literature. The nutritional guidelines were then expanded with the more recent research. The process took about two years and the Sixth Revised Edition was published in 2007.
The equine nutritionist’s gold standard for safe, effective nutritional recommendations is the Nutrient Requirements of Horses: Sixth Revised Edition.
The Committee on the Nutrient Requirements of Horses is part of The National Research Council, which is itself part of The National Academy of Sciences, the organization responsible for overseeing the research in many areas that we take for granted in our lives, including energy, medicine, engineering, and biology.
The goal has been to publish a new updated Nutrient Requirements of Horses about every ten years. Sometimes the recommendations in a new edition don’t change much from previous editions. A good example of this would be the need for selenium in our horses. Many horse owners were of the opinion, based on their own personal experiences and even observations by veterinarians in the field, that horses needed more than the maintenance requirement of approximately one mg per day for a 500 kg horse, as established in the Requirements previously. Anecdotally, there may have been a suggestion that horses needed more selenium in their diets, but there had been insufficient peer-reviewed research published to demonstrate that fact conclusively. As a result, the recommendation for selenium intake for horses did not change in the new NRC Guidelines.
On the other hand, a chapter that did have some significant updating over previous editions was that on fat. There had been significant work done on feeding fat to horses in recent years, and the NRC Nutrient Requirements of Horses has documented the research outcomes. It now includes discussion on the use of fats as an energy source in equine diets for healthy, mature performance horses, as well as lactating, and growing horses.
The Committee on the Nutrient Requirements of Horses does not include anecdotal evidence or opinions in their guidelines. Only peer-reviewed scientific research is considered when making adjustments to equine nutrient recommendations. Sometimes reference is made to research in other species of animals, and even human nutritional research when discussing the significance of a minimum or maximum dietary inclusion of a particular nutrient.
National Academy of Sciences
The National Academy of Sciences (NAS) is a private non-profit group that was first established in the United States by an Act of Congress, signed by President Abraham Lincoln in 1863. The NAS was assigned the responsibility of providing objective advice to governments in the areas of science and technology. Members to the NAS must be nominated by an existing member of the NAS and then elected by their peers. The NRC was established as a part of the NAS in 1916, to further enhance the provision of good science-based information for a government that wanted to ensure they could provide security to their citizens. Eventually the NAS grew to include National Academy of Engineering in 1964, and the Institute of Medicine (eventually renamed The National Academy of Medicine) in 1970.
The NRC, through the working group Board of Agriculture and Natural Resources, oversees the generation of nutrient requirement guides for multiple species, including most farm animals as well as many companion animals.
There are National Research Council groups in several other countries including Canada, but while they facilitate and oversee independent research, they are not part of the National Academy of Sciences in the US that provides and maintains the Nutritional Requirements of Horses.
The National Academy of Sciences was first established in the United States in 1863 by President Abraham Lincoln. It grew to include the National Academy of Engineering and the National Academy of Medicine. The Committee on the Nutrient Requirements of Horses is part of The National Research Council, which is itself part of The National Academy of Sciences.
Why are these guidelines important?
The NRC Nutrient Requirements provide nutrient guidelines for all types of horses, at all stages of life, doing all kinds of work. The document provides unbiased, science-based information about water requirements and feed processing, as well as information about feeding behaviour and forage analysis. While most horse owners understand that DE or “digestible energy” is a measure of the energy in a feed stuff, these guidelines explain exactly what DE is and how it is calculated. All chapters are backed up by a list of references. Perusing that list of references may not make for an evening of light reading, but it will show that the recommendations published are based on research, and not on hearsay.
The Nutrient Requirements of Horses is used around the world by equine nutritionists when formulating rations. Photo: Clix Photography
The 2007 edition also contains software horse owners can use to evaluate their horse’s ration. If you have an idea of the weight and body condition score of your horse, and accurate weights and nutrient analyses of his feeds, you can easily use this software yourself at https://nrc88.nas.edu/nrh/.
The publication is used by equine nutritionists around the world as a guideline for formulating equine rations, and many of the top equine scientists in the world have contributed research to it. It remains the universally accepted authority on the nutrient requirements of all equids.
How can the guidelines help horse owners and their horses?
How often do we see the promotion of equine nutritional products with claims of everything from better looks to longer life? Many products can and will make claims as to efficacy based on anecdotal evidence, but to be sure your money is being well spent, always look for claims supported by the NRC Nutrient Recommendations of Horses or other good peer-reviewed research. If marketing claims do not clearly state the evidence used to support them, be ready to contact the manufacturer to verify if their claims are based on good science, and not anecdotal evidence. There is simply no arguing over the validity of the NRC Nutrient Requirements of Horses.
Guidelines established by the National Research Council help horse owners ensure they are feeding what meets their horse’s individual nutritional needs. Photo: Shutterstock/Gertan
Next time you are thinking of perusing the internet to relax, open NRC Nutrient Requirements of Horses, instead of Facebook, and spend some time marveling at the scope of this document. All horse owners should be thankful for the work and the dedication to science and horses that has gone into the creation and the maintenance of it.
The NRC Nutrient Requirements of Horses is available for purchase online from the National Academies Press, but it can also be sourced at: https://www.nap.edu/read/11653/chapter/1.
This article was originally published in the Early Summer 2020 issue of Canadian Horse Journal.
Photo: Shutterstock/Written in Silver Visuals