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Hay Protein Content: How It Affects a Horse’s Performance

Last updated: April 13, 2023

By: Miles HenryFact Checked

It is no secret that horses need hay to perform their best. Hay is a necessary part of their diet, providing them with the fiber they need to keep their digestive system working correctly. But many people don’t know that different types of hay have different protein content levels, which can affect a horse’s performance.

Much like the human body, a horse must consume the right amount of protein to maintain a healthy diet. Since horses are herbivores and get their minerals from plants, the most common way to provide your horse with nutrients is from hay.

Hay is simply grass that has been cut, dried, and prepared for storage and is commonly used to supplement forage when your pasture isn’t producing enough grass for your horses.

When feeding performance horses, knowing the nutritional value of the hay you provide is critical. In this blog post, we’ll take a closer look at the protein content in different types of hay and discuss how it can impact a horse’s performance.

What is “hay protein content,” and why is it important?

The protein content of hay is a measure of its crude protein, which is based on the number of amino acids present. Amino acids are the building blocks of proteins and are essential for tissue growth and maintenance.

Most horses require a minimum of 8-10% crude protein in their diet in order to meet their daily needs; however, working horses likely need 15 to 20%. Hay that is low in crude protein will be less nutritious and may not provide enough of the essential amino acids that horses need.

Picture of a two year old thoroughbred in training

As a result, it is important to choose hay that matches your horse’s protein needs when feeding horses. Too much protein can cause digestive upset and can lead to an increased risk of colic.

Hay with a lower protein content is less likely to cause digestive upset but may not provide enough nutrients to support a horse’s needs. The ideal hay protein content for horses depends on the horse’s age, activity level, and health status.

For example, young, growing horses require more protein than adult horses because their bodies are still developing. Performance horses need more protein than lower-level athletes because they work harder and burn more calories.

Senior horses may also require more protein as they age, and their metabolism slows down. Consult your veterinarian for specific recommendations on the best hay protein content for your horse.

Like a top-level human athlete, everything your horse consumes will affect its performance in a race. Analyzing the protein content of the hay you are providing your horse is essential to its success.  

Picture of yearlings in a field.
Well-fed yearlings

The protein content in horse hay varies depending on the type of hay.

There are many factors that contribute to protein content in the hay, but the most significant factor is the type of hay. Here are different types of hay and their protein levels:

  • Timothy Hay – Classified as grass hay, timothy hay is very high in fiber and is easy on the digestive tract. It is low in protein and energy content but is extremely high in other nutrients. This type of hay is the best option for senior and overweight horses. It contains about 8% protein.
  • Bermudagrass Hay – This type of hay is most commonly found in southern regions and is similar to Timothy Hay in its composition. It is a standard replacement for Timothy Hay due to its ease of transport and availability. This type of hay also has a low protein content and is easy to digest, thus making it an excellent option for horses with digestive issues and senior horses. It has a protein content of about 8.4 to 10 percent.
  • Orchardgrass – Known for its good flavor and high fiber, orchardgrass is becoming a favorite in the horse community. In addition to these qualities, it has a high protein content compared to bermuda or timothy hay. A unique quality of this type of hay is that the nutrient content is not relative to the time it needs to be cut. 
  • Oat hay – Oat hay is one of the most versatile types of hay because it can grow throughout the cool spring and fall weather. If cut at the right time, when the oats bloom, it is the best for young livestock consumption. This type of hay is more commonly utilized for livestock rather than horses. 
  • Alfalfa – For all hay-consuming animals, alfalfa hay is supreme. This type of hay is an excellent source of high-quality protein. Due to the high amounts of protein, a horse can quickly get bloated on alfalfa hay; therefore, it is advised to use other types of hay in addition to the alfalfa. This type of hay has around 12 to 15 percent protein content. 
Picture of an underweight two-year old horse.
Malnutritious Yearling

What are the signs your horse is lacking protein? (and ways you can supplement their diet.)

You should be able to see many tell-tale signs when your horse isn’t getting enough protein. High-performance horses, broodmares, foals, weanlings, and yearlings are the most susceptible to becoming deficient in protein levels. 

  • Weight Loss – This can occur suddenly or gradually over some time. This is one of the easiest things to notice when your horse lacks protein. Lack of energy will also come with the loss of weight. 
  • Abnormal Hoof Growth – Paying attention to your horse’s hooves is very important. Noticing a lack of growth can help determine if your horse lacks protein.
  • Slow-healing Wounds – A horse will commonly acquire minor cuts and bruises throughout its life. The issue arises when those cuts and bruises are not healing correctly. If your horse seems to take a long time to heal, it is advised to check its protein intake. 
  • Dull Hair Coat – Another easily recognizable sign is noticing a decline in your horse’s coat. Documenting a horse’s life with photographs is an excellent way to maintain this by having a reference from the past to be sure the coat is not declining. 
Picture of bermudagrass hay next to alfalfa hay

How can you tell if a type of hay has too much or too little protein?

Hay is an important food source for many animals, and the protein content of hay can vary widely depending on the type of hay and the growing conditions. The first step in determining whether a particular type of hay has too much or too little protein is to take a sample of the hay and have it analyzed by a laboratory.

The lab will measure the amount of crude protein in the hay and provide a report that includes the percent protein by dry weight. This information can then be used to decide whether the hay has an appropriate protein level for the animals that will be eating it.

In general, hay with a higher protein content is better for younger animals, while hay with a lower protein content is better for older animals. Hay that is too low in protein can cause health problems, such as poor growth, while hay that is too high in protein can lead to digestive issues.

Therefore, selecting hay with an appropriate protein level for the animals consuming it is crucial. Maybe you don’t have time to take your hay in for a complete analysis. Is there a way to tell without going through that hassle?

Below is an “Ask the Vet” YouTube video discussing horses that eat too much protein.

The truth is, no, you can not. Even after knowing the time of yield, species, and maturity, it is tough to precisely know the protein content of that particular specimen. The same hay, cut and processed simultaneously but in different pastures, can significantly change protein content.

However, there are some general rules we use to check our hay. One way you can tell if hay has too much or too little protein is by looking at the color of the leaves. If the leaves are yellow, it means that the hay is low in protein.

On the other hand, if the leaves are green, it means that the hay is high in protein. Another way to tell if hay has the right amount of protein is by looking at the texture of the hay. If the hay is coarse, dry, and moldy, it is typically low in protein and not fit for horse consumption.

However, if the hay is soft and fresh smelling, it is generally higher in protein. I also find hay that is high in protein costs more.

With all this being said, the next best thing you can do would be to get information from your hay dealer. Knowing the different types of hay species and their protein contents will help, but you will never know their authentic content without a complete analysis. 

Picture of my horse grazing.

Are there risks associated with feeding your horse too much or too little protein?

When it comes to feeding horses, there is a lot of debate about the ideal amount of protein. Some people believe that hay should be the primary source of protein for horses, while others argue that grain is necessary to provide the right balance of nutrients.

So, what does the research say? Are there risks associated with feeding your horse too much or too little protein? Generally speaking, hay is a good source of protein for horses. However, the type of hay and the quality of the hay can affect the amount of protein that your horse gets.

For example, alfalfa hay is higher in protein than grass hay. If you’re feeding your horse hay that is lower in protein, you may need to supplement it with grain or another source of protein.

There are also some risks associated with feeding your horse too much protein. One study found that horses fed a diet high in protein were more likely to suffer from obesity and joint problems.

In addition, a horse that consumes too much protein is at a greater risk of contracting diseases, and often the symptoms are worse for horses with too much protein. There is also evidence that too much protein will break down your horse’s tissues, organs, and overall structure.

Kidney problems, arthritis, and hypothyroidism are just a couple of issues associated with an overload of protein. So, if you’re unsure about how much protein your horse needs, it’s best to consult with a veterinarian or equine nutritionist.

Picture of a horse eating hay.

Tips to ensure your horse gets the correct amount of protein in their daily hay ration. 

Hay is an essential source of nutrition for horses, providing them with essential nutrients like protein. However, ensuring that your horse gets the right amount of protein from their daily hay ration is vital. Here are a few tips to help you ensure that your horse is getting enough protein:

  • Make sure to feed high-quality hay. The higher the quality of hay, the higher the protein content will be.
  • Be aware of how much hay your horse is eating each day. The average horse needs about 2% of its body weight in hay each day.
  • You can also supplement your horse’s diet with other protein sources, such as grain or pellets. However, it’s important to talk to your vet before making any changes to your horse’s diet.

Feeding a horse with an adequate amount of nutrients in hay is not a difficult task. It is essential to be precise and accurate when going through this process. The hardest part is getting an accurate analysis of the hay you provide because sometimes dealers do not tell the whole truth.

Once it is determined what is actually in the hay, you must figure out the amount your horse needs based on its activity level. After determining the amount, consistency is critical.

Always have a schedule and provide your horse with the optimal amount at the same time each day so you do not forget. Adjust your horse’s rations as needed based on certain upcoming events or shortly after an event.  

Following these tips can help ensure that your horse gets the right amount of protein from their hay ration each day.

Picture of a 44 lb. bale of hay.
Bale of Alfalfa hay


What is a good source of protein for horses?

Horses are herbivores, and their diet consists primarily of grass and hay. Hay is a good source of high-quality protein, essential for maintaining muscle mass, coat condition, and reproductive function.

What kind of hay is bad for horses?

Hay is an essential part of a horse’s diet; however, not all hay is created equal. Some types of hay contain high nitrates and sugars, such as Sorghum, Sudan, Johnsongrass, and Pearl Millet, which can be dangerous for horses.

Below is a handy printable pdf about protein content for your horses.

Infograph quicklist of Protein content for horses.