• Abi Kroupa

Types of Hay and When to Feed Them

Owning horses over the years, I have been asked this question multiple times, "What type of hay do you feed?" Personally, I feed timothy hay with less than 10% alfalfa in it. My answer to why I feed it isn't very exciting or profound. I feed it because that's what I have always fed and my horses have always seemed to love it. But that got me thinking, "Just because I have always fed it, doesn't mean it's necessarily the best option."

So, what is the best type of hay for our equine friends? There are so many various opinions on hay from fellow horse owners, vets, and equine nutritionists. I have noticed over the years that most vets and horse hospitals in the southeast United States tend to feed Timothy hay, but this is just a personal observation. I truly believe the best type of hay for your horse depends on a few factors including their behavior, performance level, medical history, and availability of good quality forage in your area.

One thing I do know is that even though every horse's nutritional requirements may vary, there are a few nutritional considerations that every horse owner should know.

To get started here are some common terms used when evaluating hay:

Crude Protein (CP):Protein levels in hay can vary. The younger the hay is when it was cut, the higher the protein level will be. Protein levels can range from 8% to 14% in grass hay, and 15% to 22% in legume (alfalfa) hay. In general, a growing horse needs between 12% and 18% protein in their diet for proper growth and development, while most mature horses will do fine on lower protein hay (10% – 12%). Horses that are in training may need more protein to support increased muscle development and replace nitrogen that is lost during exercise, but you also need to keep in account the amount of protein being feed in your daily grain ration.

Non-Structural Carbohydrates (NSC):This term is used to describe the sugar and starch content in hay. NSC's are important since these are the carbohydrates that are broken down and absorbed into the bloodstream as glucose. Horses with insulin resistance and metabolic issues are typically fed a low NSC diet.

Calcium (Ca) and Phosphorus (P):The balanced ratio between these two minerals, which varies among different types of hay, is very important because the two work closely together. Ideally, the calcium to phosphorus ratio in horses should be between 3:1 to 1:1. In other words, a horse needs at least as much calcium in his diet as phosphorus, never the reverse.

Now that we have reviewed a few basic terms let's look at the difference between alfalfa (legume) hay and some grass hays.

Moisture:Ideally hay moisture should range between 10% – 17%. Moisture levels will vary from cut to cut. Hay under 10% could be dusty and dry. Hay over 18% has a high risk of mold. Hay over 25% moisture can be a potential fire hazard and bales may spontaneously combust. (more on this in a future post)


One of the biggest differences between alfalfa hay and grass hay is the protein content. On average, alfalfa hay has much higher levels of protein, ranging from 15% to 21% depending on when the alfalfa was cut. While most adult horses only need around 10% to 12% protein in their diet, higher protein is important for young growing horses, working performance horses, and for lactating mares.

The energy content is also different between alfalfa and grass hays. Alfalfa hay typically has more calories per pound than grass hay, so if you are feeding your horse alfalfa hay, he may need to consume less hay to maintain his body weight. This difference is related to the fiber content of the hay; alfalfa hay is lower in fiber, while grass hay is higher in fiber which allows the horse to eat more hay without putting on extra weight.

Another major difference between alfalfa and grass hay is the mineral profile. Alfalfa hay typically has higher levels of calcium when compared to the amount of calcium in grass hay. The phosphorus content, however, is usually not that different between the two hays. And, of course, the mineral content in all hays will vary depending on the region in which it was grown as well as the soil conditions.

Horses that have insulin resistance and are prone to laminitis may be sensitive to alfalfa, most likely because alfalfa has more sugar and is higher in starch than most grass hays. So, if your horse is insulin resistant and you are considering feeding him alfalfa hay, it would be best to discuss this option first with your vet.

Alfalfa Hay Analysis (average)

Crude Protein: 15.0% – 22.0%

Crude Fiber: 25.0%

Non- Structural Carb (NSC): 8.75% – 13.25%

Ca:P Ratio: 5.3:1


Now let's turn our attention to the two most common grass hays: Timothy and Orchard.

Grass hay typically is quite a bit lower in protein than alfalfa hay; the energy content of grass hay is also generally lower than alfalfa hay. For many people who have horses, especially mature horses, non-working horses, horses on high protein grain, or horses that are not used for breeding, grass hay is often preferred over alfalfa hay because of these lower protein and lower energy levels. Grass hay is also quite often a good choice for senior horses, as it's easier on the kidneys due to its lower protein content and is also easier to chew and digest.

Grass hay typically has lower nutritional values than alfalfa hay, and is also lower in calcium, making it closer to a more desirable Ca:P ratio (between 3:1 to 1:1). Also, grass hay is often less dusty than alfalfa hay, so it a good choice for horses that have respiratory issues. And unlike alfalfa hay, grass hay is not as subject to the potential risk of blister beetles.

Here is a quick look at some of the more popular grass hays and their typical profiles:

Timothy Grass Hay

Timothy Grass is the traditional favorite among horse owners. Much of this tradition is because Timothy was one of the first grasses cultivated for horse hay. Therefore, feeding Timothy Grass has a well-established comfort level with horse people. High-quality Timothy Grass contains a lower amount of protein, usually testing at approximately 8% protein. It has a consistent and balanced ratio of calcium to phosphorus and low to moderate calorie content. Timothy Grass is also a rich source of fiber.

Timothy Grass Hay Analysis (average) Crude Protein – 6.0% – 10.0% Crude Fiber – 30% NSC – average of 12% (range 7% – 18%) Ca:P Ratio – 2.2:1

Orchard Grass Hay

Orchard grass hay is not as nutrient-sensitive to the time of cutting as the other grass hays and is also less expensive than timothy hay. Orchard Grass is the emerging super-star of the horse hay world. Orchard Grass is a highly palatable grass with high nutrient content. Orchard Grass is higher in protein (10-12%), higher in calorie content and contains similar balance levels of calcium and phosphorus as Timothy grass.

Orchard Grass Hay Analysis (average) Crude Protein – 10.0% – 12.0% Crude Fiber – 30% NSC – average of 12% (range 7% – 18%) Ca:P Ratio – 1.5:1

These are just some of my findings on different types of popular hay fed to horses along with their nutritional difference. Hopefully, this information will help you in deciding which is the best hay to feed your equine friends.

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