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Selecting and storing horse hay

Quick facts

  • Plants have more fiber and less protein as they mature.

  • Don’t be too concerned about hay color. All hay needs mineral and vitamin supplementation.

  • You can feed quality, rained on hay to horses.

  • Horse quality hay should be baled between 10 and 15 percent moisture.

  • Store and protect hay from moisture to best prevent spoilage.

The digestive system of the horse has been designed to efficiently utilize forages, and most horses can fulfill their nutrient requirements on these types of diets. You should choose your forage based on your horse’s nutrient needs. A variety of factors, including plant species and maturity should be considered when making this decision.


Legumes and cool-season grasses are common horse forages. Know what percent grass and legumes are in your hay before buying it. Average nutritive values of forages commonly fed to horses are shown in table 1. 


Plant maturity

The maturity of a plant affects forage quality. Young, immature plants are nutrient dense and contain less fiber. As the plant matures, the proportion of fiber in the plant increases. This can decrease plant digestibility.

Most horses do well on mid-maturity forages. Horses that require higher nutrient needs (e.g. lactating mares) benefit from young, less mature forages. More mature forages are a good choice for easy keepers.

The following indicate a more mature plant:

  • Flowers in legumes

  • Seed heads in grasses

  • Thick stems

Grasses harvested just as the seed heads start to form have excellent fiber digestibility and energy availability, and will produce leafy hay.

The leaf to stem ratio of a plant is also key. As a plant matures the leaf to stem ratio declines. Compared to stems, leaves have,

  • More protein

  • More digestible energy

  • Less fiber than stems


A horse’s mouth, lips and tongue are very soft. Thus, they will be more willing to eat softer hay and in turn, waste less. Even if the hay has good nutritional value, it must be appealing to the horse otherwise they’ll waste it.


Sweet smelling hay is appealing to people and horses and indicates available energy (sugar). A sweet smell is an incentive for the horse to eat the hay and get its full nutritional value.


Green is appealing to horse owners and indicates the presence of vitamin A. Bleached color indicates exposure to sunlight or rain. In this case, vitamin A content is lower, but other essential nutrients still remain.

Despite the color, you must supplement any hay with an appropriate vitamin-mineral mix.

Don’t be too concerned about color. Remember, weeds are also green in color.


You can feed quality rained on hay to horses.

Hay quality declines the most when rain occurs after the forage has partially dried. Alfalfa dry matter declined 22 percent when exposed to an inch of rain after one day of drying. Similar hay without rain damage lost only 6.3 percent.

Rain (or soaking hay in water) can reduce the nonstructural carbohydrate (i.e. sugar) content of the hay. Good quality, rained on hay can benefit horses that are sensitive to forage sugar content.

Learn more about determining the value of rained on hay. 


The cutting (1st, 2nd or 3rd crop) doesn’t predict the hay’s nutrient content. Maturity at the time of cutting is the basis of the hay’s nutritional value.

Plants that grow under cooler temperatures build more digestible fiber. Thus, 1st crop hay may have more and easier to digest fiber.


Horse quality hay should be baled between 10 and 15 percent moisture.

  • Hay baled over 17 percent is at risk of molding.

  • Hay baled over 25 percent is at risk of severe heat damage and serves as a potential fire hazard.

Using propionic acid can help prevent molding at the time of baling. Producers commonly use it when the hay is between 17 and 25 percent moisture. Propionic acid-treated hay may smell slightly acidic, but is safe for horses.


Don’t feed horses moldy hay.

Nearly all feed has some mold spores. Excessive mold may cause coughing, heaves or allergic reactions if horses inhale it. Horses with heaves are often more sensitive to mold spores or dust.

Always inspect the inside of at least one bale before buying the hay. Hay stored inside that isn’t moldy has a low risk of getting moldy.

Learn more about mold in hay.

Bale type

Hay can be baled in a variety of ways. Depending on your storage and feeding methods, each type has pros and cons. 


Out of state hay needs

The certified noxious weed seed-free forage program assures that certified forage meets the minimum standards to limit the spread of noxious weeds. Minnesota doesn’t require you to use certified hay. It’s voluntary for you to use certified hay when trail riding and camping in Minnesota public parks.

If you plan a trail ride or camping trip with your horse on public lands in the western U.S., you must use certified hay.

Contact the Minnesota Crop Improvement Association for a list of producers of certified noxious weed seed-free forage in Minnesota: 800-510-6242.


Tips for storing hay to maintain good condition and reduce losses.


Hay testing

Hay tests determine the contents of hay such as:

  • Moisture

  • Protein

  • Minerals

  • Sugar

  • Energy

Be sure to request an equine analysis and remember that the analysis is only as good as the sample you submit.

Learn more about analyzing forages.

Krishona Martinson, equine Extension specialist; Paul Peterson, former forage agronomist; and Jennifer Earing, former postdoctoral student, College of Food, Agricultural and Natural Resource Sciences

Some information taken from University of Kentucky, Virginia Tech, University of Wisconsin, and Pennsylvania State Extension.

Reviewed in 2018

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