Evaluating and Purchasing Hay for Horses

Forage—hay or pasture—must be the foundation for every feeding program for equines. Forages provide nutrients, adequate chewing time, aid in proper transit through the gastrointestinal tract, and are the main substrate for bacterial digestion in the hindgut. Table 1 lists the expected daily forage and grain intake as a percentage of body weight for various classes of horses. To calculate the pounds required, multiply a horse’s body weight times the percentage. Mature, idle horses should be provided 1.5 to 2% of body weight in the form of forages. This is equivalent to 16.5 to 22 pounds of forage for a 1,100-pound horse. The mature, idle horse will eat 3 to 4 tons of hay per year. For working horses, a minimum of 1% of body weight in forage is important for their digestive tract. Because forage is such a large component of the horse’s diet, knowing how to evaluate forage is critical.

Expected daily forage and grain intake as a percent of body weight

Class of horse




Mature, idle horse

1.5 – 2.0

0 – 0.5

1.5 – 2.0

Working horses

1.0 – 2.0

0.5 – 1.5

1.5 – 2.5

Mare, late gestation

1.0 – 2.0

0.5 – 1.0

1.5 – 2.5

Mare, lactation

1.0 – 2.0

0.5 – 1.5

2.0 – 3.0


1.0 – 1.5

0.5 – 1.5

2.0 – 3.0


1.0 – 1.5

0.5 – 1.5

2.0 – 2.5

Legumes and Grasses

Forages are the stems, stalks, leaves and heads of plants, with or without the seeds or grain. Forages are divided into legumes and grasses. Grasses consist of cool-season and warm-season species. Differences in the nutrient composition are related to differences in structural carbohydrate concentrations, leaf content, and the presence of unsuitable components that affect digestibility. It is important to realize forage nutrient content varies greatly with the stage of maturity at harvest and soil conditions under which the forage was grown. Regularly testing hay, especially as feed sources change, allows horse owners to better meet the nutrient needs of their horses.

Table 2 lists the nutrient variation between cool-season grasses, warm-season grasses, and legumes. The range in value is due to maturity, condition, and nutritional value. Legumes are excellent, high-quality feeds for horses. Legumes provide higher protein, energy, and calcium than grasses. Alfalfa is the most common legume used for hays, cubes or pellets and often comprises a portion of hay for horses. Common clovers are red, white, and alsike clover. Alsike clover should be avoided as it can cause liver damage and photosensitivity in horses. Horses can slobber or salivate excessively when primarily consuming clovers, but alfalfa will occasionally cause slobbers.

Legumes generally contain less fiber than cool or warm season grasses and more energy. Legumes store carbohydrates as starch and have a moderate to low non-structural (digestible) carbohydrate (NSC) level. Legumes are excellent for horses with high calorie and protein requirements or horses requiring a restricted NSC diet. Because of the calories, these may need to be restricted for overweight horses.

Cool-season grasses are grass types that grow well in the cool weather of the spring and fall. Warm season grass thrives in hotter weather, so these grow in late spring and summer. Cool-season grasses include Kentucky bluegrass, meadow fescue, orchardgrass, perennial ryegrass, smooth bromegrass, Timothy, and tall fescue. Examples of warm-season grasses are Indiangrass and teff.

Cool season grasses, also known as C3 grasses, have a moderate-to-high energy (calorie) and protein content compared to warm season grasses (see Table 2). The storage form of carbohydrates in C3 grasses is sucrose and fructan. For warm season grasses, also known as C4 grasses, the storage form of carbohydrates is sucrose and starch. NSC in forages is the sum of starch, simple sugars and fructans. Notice the NSC in cool-season grasses is variable and can be potentially high (>15%), which can cause problems in horses with metabolic problems. Cool-season grasses are recommended for horses with moderate-to-high calorie and protein requirements, and are not sensitive to NSC. Warm-season grasses have a moderate (15%) to low (<12%) NSC composition. Because of the lower energy, NSCs, and protein in C4 grasses, these are useful for horses requiring lower calories and protein in their diets. These may not be capable of meeting a broodmare’s or hard-working horses’ energy or protein needs        

Table 2. Nutrient variation between cool-season grasses, warm-season grasses, and legumes. The range in value is due to maturity, condition, and nutritional value.


Cool Season Grasses

Warm Season Grasses


DE (Mcal/kg)




CP (%)




NDF (%)




ADF (%)




Ca (%)




P (%)




NSC levels

Variable, potentially high (>15%)

Moderate (15%) to low (<12%)

Moderate (15%) to low (<12%)

1DE, digestible energy; CP, crude protein; NDF, neutral detergent fiber; ADF, acid detergent fiber, Ca, calcium, P, phosphorus

  • Data reproduced from Equi-Analytical Laboratory Services Interactive Common Feed Profiles Library from May 2000 through April 2022 and Richards, D., B. Nielsen, and C. Finno. Nutritional and Non-nutritional Aspects of Forage. Vet Clin Equine 37 (2021) 43–61 https://doi.org/10.1016/j.cveq.2020.12.002
Selecting Hay

Horses should be fed hay that is of good to high quality. When selecting hay, factors to consider include the composition, maturity, color, and foreign material present. Composition includes the type of hay – alfalfa, grass or a mix of both.

Evaluate the Maturity of The Hay

The stage of maturity, determined by the stem-to-leaf ratio, is the most important selection criteria for hay. The maturity of the plant is not related to a particular cutting, but rather to the stage of maturity when the plant was cut. Mature hay has a much higher stem-to-leaf ratio, resulting in a lower nutrient value of the hay. Leaves are high in energy and protein, while stems are more fibrous and have a lower nutritive value. Plant maturity also can be assessed by the number of seed heads of grasses or flowers of legumes present in the hay.

  • As the plant matures, and the plant grows tougher stems so it can stand up vertically. Quality of forages increase up to the time grasses start to get seed heads or legumes flower. As plants progress through seed head or flower bud emergence and seed formation, the concentration of structural carbohydrates and lignin (non-digestible fiber) increase and crude protein decreases. For every 1% increase in lignin, the digestibility of the forage dry matter decreases 3 to 4%.
  • The ideal time to harvest legumes is the bud or vegetative stage just prior to flowering.
  • The ideal time to harvest grasses is the boot stage when the seed head swells in the leaf sheath but has not yet completely emerged. Grass hays range from vegetative to late heading where seeds form. During the vegetative stage, the plants are leafy and contain fine stems. The reproductive stage is the period when the seed head emerges, develops, and pollination occurs, resulting in seed development. During seed formation or late heading, stems often are coarse and hay or plants are yellow or brown in color.

Evaluate Leafiness and Leaf shatter

Leaves contain more non-structural (digestible) carbohydrates and protein than stems. The more leaves, the more nutrient-dense and digestible the hay is.

  • Evaluate the texture by feeling and bending the leaves and stems. Stems of hay should be soft and pliable, rather than coarse and stick-like. The nutritional value decreases as the texture of the stem and leaves changes from fine and easily bendable to rigid and brittle. Early-maturity grass hay has fine, bendable stems and is indistinguishable by feel from leaves. In good-quality grass hays and early maturity, high-quality alfalfa, lignification begins in the stems, but the leaves will be soft and easy to bend. The next stage is characterized by rigid stems and fewer leaves. Hay may feel brittle when bending the stems. Poor hay has inflexible, brittle stems. The highly lignified structures have little nutritional value.
  • Leaf shatter results in loss of leaves, and therefore, decreased nutrients. Legumes often have higher leaf shatter losses. The more leaves legume hay loses, the poorer the nutritive value of that legume.
  • Leaf loss also may mean the hay was baled too dry. Baling hay at a lower moisture level (too dry) will result in leaf shatter. Hay baled at ideal moisture levels (17 to 20%) has a higher nutrient level due to better leaf retention.

The image below shows examples of stems and leaves in grass and alfalfa. Image A illustrates grass stems, B illustrates alfalfa stems and some leaves, and C illustrates shattered alfalfa leaves.

Hay Stems and Leaf Shatter

Look at the Color

Ideally, hay should be a bright green color. The greener the hay, the more carotene (a Vitamin A precursor) and vitamin E. Greener hay also indicates the plant was not subjected to any adverse conditions during curing or storage. Yellowing will occur from direct exposure of stored hay to sunlight, cutting more mature hay, or exposure to rain during the curing process. Often, sun bleaching only affects the outside of bales, so look at the inside of a bale. If the hay is brown, it is mature, less nutritious and may be less palatable to horses. Yellow and brown plants have lower carotene content and palatability. Examples of the variation in colors is shown in the image below.

Color is a poor indicator of forage quality when considered alone, as bright green weeds may have lower nutrient composition than brown alfalfa. Don't pay a premium just because it is greener. Nutritionally, other variables are more important, such as the maturity of the plant.

Hay bales

Hay Should Be Free from Mold

Moldy hay most often occurs when hay is baled at high moisture levels (20% or more) without a preservative added. Look for visible mold and mold spores by inspecting a few bales of any purchased or stored hay. Mold spores create dust. Smell the hay. Some hays smell musty, but do not have visible mold. Hay should have a sweet smell indicating proper curing. Hay stored outside can be more susceptible to developing mold. Also, hay baled at a higher moisture level will have an increased risk of spontaneous combustion.

Moldy hay

Hay Should Be Free from Foreign Matter or Weeds

  • Look for foreign material in the hay. Hay and forages should be free of weeds. Weeds and wood often are less palatable, may be toxic, and may contain viable seed that will become a weed problem on your land.
  • Look for coarse crop residue such as straw, corn stalks, and corn cobs that often are less palatable, and usually very low in nutritive value.
  • Look for such things as plastic, manure, dead animals, and wire, which are harmful to animals and may affect palatability and aroma.

Use of Hay Stored for More Than One Year

Hay that is stored under cover and protected from sun and rain loses very little of its nutritional value. The amounts of energy, protein, calcium, phosphorus, and other nutrients and minerals decrease slightly during the first month or two of storage, and remain consistent even after two years of storage. The only significant loss is carotene (vitamin A), but the greatest loss of vitamin A occurs right after harvest. To prevent a vitamin deficiency, horses should receive supplemental vitamin A when feeding hay that has been stored for more than one year. The feeding of commercial grain mixes or balancers, supplemented with vitamins, easily fulfills vitamin requirements for horses. Remember, under no circumstances should old hay be fed if it has been compromised by dust, moisture, mold, or foreign objects.

Purchasing Hay

Knowing how much hay is required by the horse helps determine the amount of hay to be purchased. If a 1,200-pound horse requires 2% of its body weight per day in hay, the horse needs 24 pounds of hay per day. Feeding 24 pounds per day equals 720 pounds for one month, and 8,760 pounds or 4.3 tons for one year. One ton of hay requires 200 to 330 cubic feet in storage space. Therefore, four tons of hay requires 1,000 cubic feet or a storage area roughly 9 feet high, 11 feet wide and long (9’ x 11’ x 11’). This is the approximate size of one stall.

Hay is sold in small squares, large squares, and round bales. The price of hay is by the bale or ton. The bale type should work with the system of the buyer. Small rectangular bales weigh between 34 to 130 pounds. If your bales of hay weigh 50 pounds, you need 8,760 pounds per year, divided by 50 pounds per bale, which equals 175 bales per year. Large rectangular bales are 2' X 3' X 8' or 3' X 3' X 8' and weigh between 400 to 1,200 pounds, which is equivalent to 16 to 24 small 50-pound square bales. This would feed one horse 36-54 days. A large round bale weighs between 400 to 2,000+ pounds, which is equivalent to 10-24 small 50-pound square bales. This would feed one horse 20-50 days.

Evaluate bale size and purchase price. Purchasing hay by the ton usually is less expensive than the price per bale. Table 3 illustrates comparisons in bale weight, the number of bales per ton, the price per bale, and price per ton. If a bale weighs 35 pounds and costs $5, it would cost $285 per ton. If the bale weighed 55 pounds and cost $5, it would cost $185 per ton.

Table 3. Comparison of bale weight, approximate bales per ton, price per bale, and price per ton.

Bale Weight

Approximate Bales/ton

Price per bale

Price per ton

35 lbs.








45 lbs.








55 lbs.








Listed below are items to consider when purchasing hay.

When buying hay, define and communicate the terms of sale.

  • What is the point of sale?
  • Is the price at the seller's barn or stack, or at your barn?
  • Is the hay loaded on the buyer's truck and delivered?
    • Is the cost of delivery in the original price, or will it be added to the original price?
  • Who is responsible for stacking hay in the storage area?

Effective date of price

  • How long is the price in effect?
    • one month
    • one week
  • Is the price negotiable?

Quantity to be purchased

  • What is the contracted amount?
  • Does the hay have to be picked up or can it be delivered?
  • Is all the hay to be delivered at one time or over some specified period of time?

Payment Terms

  • What are the payment terms?
  • Will payment be collected on delivery or within 30 days after delivery?

Delivery Considerations

  • Is there good truck access to the site where the hay is to be stored?
  • Are you expected to unload and stack?
  • Does the buyer (you) need to be present to help unload or provide access to the storage area?
Tips for Choosing the Best Hay for Your Horse
  • It's what’s inside that counts. Examine leaves, stems, and flowers or seeds pods for maturity. Choose fine-stemmed, green, leafy and soft-to-touch, compared to thick and brittle leaves and stems. If given a choice between two or more different lots at a hay sale, choose the leafiest.
  • Avoid over-cured, excessively sun-bleached hay, or hay that smells moldy, musty, dusty, or fermented.
  • Avoid hay that contains significant weeds, dirt, trash, or debris.
  • Reject bales that seem excessively heavy for their size or feel warm to touch, because these may have been baled too wet.
  • When possible, purchase and feed hay within a year of harvest to preserve its nutritional value.
  • Store hay in a dry, sheltered area out of rain, snow, and sun.
  • If possible, purchase hay that has been tested, or test the hay that you purchase, for important feed quality components.
  • Purchase a year's supply of hay at one time, to get quality forage at the lowest cost.
  • Feed hay from a hay feeder to minimize hay losses. Hay feeder cost easily can be recouped when considering potential losses.

Prepared By

Peggy Auwerda, associate professor in animal science and extension equine specialist at Iowa State University, peggy@iastate.edu; Meaghan Anderson, field agronomist with Iowa State University Extension and Outreach, mjanders@iastate.edu


  1. Forages for Horses in Iowa https://store.extension.iastate.edu/product/16406
  2. Equi-Analytical Laboratory Services. https://equi-analytical.com/
  3. Richards, D., B. Nielsen, and C. Finno. Nutritional and Non-nutritional Aspects of Forage. Vet Clin Equine 37 (2021) 43–61 https://doi.org/10.1016/j.cveq.2020.12.002