What is Hay?

Hay is a plant that has been cut, dried, và stored for animal feed. Many plants can be used as hay, but in Iowa today, alfalfa & clover are the most common. As Americans moved west onto the Great Plains in the 19th century, they would often use the prairie grasses that were growing there khổng lồ feed their livestock.

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Hay versus straw: Hay và straw are commonly confused. Hay is made from the stems, leaves, và seed heads of plants that are fresh. It is cut and baled when it has the most nutritional value, & is fed lớn livestock. Straw is also made from the stems & leaves of plants, but is cut after of the plants have been allowed khổng lồ mature & the seed heads have been harvested for something else. Straw has very little nutritional value, and is best used as bedding for animals.

History of Hay

Many different plants have been used throughout history lớn feed animals. The first farmers on the prairie would cut the prairie grasses và use them to feed their livestock. Timothy grass & clover, both plants native to lớn Europe, were the most common plants used for hay in the early 20th century.

Alfalfa quickly replaced timothy and clover after it was introduced in Iowa at the end of the 19th century. Alfalfa became the most common plant for hay. It is believed that alfalfa is native to in central Asia where it was first used lớn feed animals. Alfalfa spread rapidly lớn all parts of the world. By the early 1700s, alfalfa was being grown in Central and North America. By the mid-1700s, the British colonies of New York, Virginia, & Georgia all reported growing alfalfa. By the 1850s, alfalfa was being grown in California.

Today, alfalfa is still the main plant for hay.

How Crops Become Hay

In general, three steps are required khổng lồ turn a green crop into what can be called hay: cutting, drying, & baling. Then, hay must be stored properly in order for it to lớn hold onto the nutrients. If hay becomes wet, or if it sits in the sun, nutrients can be lost.

Cutting Hay

Cutting tốt has been, & can be, done in many ways.

By hand: For thousands of years, xuất xắc was cut with hand-held tools like a scythe.By horse-drawn machine: In the 19th century, many machines that could cut giỏi were invented that could be pulled with horses. Many giỏi mowers were invented in the 19th century.By machine pulled by a tractor: When tractors were invented, the tuyệt mower was improved as well.


Hay must dry before it can be baled. When giỏi is cut, farmers leave it in the field and allow it to partially dry. Then the farmer will rake the xuất xắc into what are called windrows. Rain can damage the hay the most at this stage. Rain slows down the drying process, and too much rain can cause the giỏi to begin to lớn spoil in the field.

Baling Hay

The first hay baling equipment was invented in the late 1800s. These early baling machines were stationary, và the hay had khổng lồ come khổng lồ it. Tốt was carried by hand khổng lồ wagons that then took the hay to these early balers, where the machine pressed the tuyệt into square bales. By the 1930s, giỏi baling equipment could be pulled by tractors & pick up the xuất xắc from the ground. This saved the farmer a lot of time và energy!

Storing Hay

Stacking is the oldest method of storing hay, and different parts of the world stacked xuất xắc differently. On the Iowa prairie in the 1840s & 1850s, these stacks sometimes doubled as housing for animals. As the farm improved, larger barns were built that could store more than just tools & seed. Large barns often held massive amounts of xuất xắc stacked in the center. In 1900, loose tuyệt was stored in the barn. The xuất xắc would be carried by wagon to the barn where it would be put into the hay loft.

Interesting Facts about Hay

How many acres of tốt were harvested in Iowa in these years?

1900 – 2,577,000 acres1957 – 3,744,000 acres2016 – 910,000 acres

How many tons of hay were produced in Iowa in these years?

1900 – 3,608,900 tons1957 – 7,938,000 tons2016 – 3,210,000 tons

What was the value of the tuyệt crop produced in Iowa in these years?

1900 – $23,458,656 (in 1900 era dollars)1957 – $123,039,000 (in 1957 era dollars)2016 – $294,915,000 (in năm 2016 era dollars)

Sources: 1900: Van Hooten, G. H. The Iowa Yearbook of Agriculture. Des Moines: B. Murphy, 1901.1957: Iowa State Department of Agriculture. Second Biennial Report of Iowa Book of Agriculture. Des Moines: State of Iowa, 1958. 2016: United States Department of Agriculture, National Agricultural Statistics Services.

Hay Today

Today, the process for growing giỏi still involves letting the plants grow khổng lồ maturity, then cutting it, letting it dry in the sun, raking it, and gathering it up in some form, whether that be round or square bales, or as loose hay. Farmers today have different technology và equipment for growing, baling, & storing hay.

Preparing the soil

The land is prepared like it would be for any other vegetable crop. Farmers will thử nghiệm the soil to lớn determine if any fertilizers need to lớn be added. If needed the farmer will then địa chỉ cửa hàng the appropriate amount of fertilizer. The field must be free from weeds as much as possible. Weeds will make it difficult for the alfalfa, clover, or timothy khổng lồ grow.

Planting and growing

Some fields are always used to grow hay, and don’t require re-planting every year. In other cases, tốt is a part of a crop rotation, where farmers plant different crops on the same field in different years. Hayseed can be a mixture of many types of seeds, with alfalfa, clover, & timothy being among the most common. The seed can be planted many ways, from being spread by hand for small areas, to being planted with machines like a grain drill.

Cutting hay

Cutting hay is done when the tốt has the most nutritional value. Usually that is after about 60 days when harvesting alfalfa for hay. The same field of giỏi can be cut two or three times in the same season. Machines that can cut hay are called mowers.

Today there are two types of mowers used khổng lồ cut tuyệt that can be pulled by machines.

Rotary disk mowers have several round discs that cut the hay.Sickle bar mowers have a bar with teeth that cut down the hay.

Stacking và baling

Throughout the 20th century, hay baling equipment continued to improve. In the early part of the century, a machine was invented that could make round giỏi bales. Round xuất xắc bales were not common until after a professor và a group of students at Iowa State University came up with a much improved design for a machine that could make round bales.

In the mid-1960s, Wesley Buchele, a mechanical engineer at Iowa State University, working with graduate students, developed a mechanical baling machine that would produce a giant, 700 lb. Round bale. One person with a tractor could handle these huge bales, from harvest lớn baling to transporting to lớn feeding livestock, without ever touching the hay. Today, round bales are the most common way to store tuyệt in the United States.

Transporting and Storing

Transporting baled tuyệt to the barn today is done either by moving each bale with a tractor (which takes a long time!) or putting many bales of xuất xắc onto a wagon and taking to the barn that way. Today, square or round bales of xuất xắc can be stored in a barn or other outbuilding with a roof to protect it as much as possible from the weather. Tốt that is left outside has some sort of covering khổng lồ protect it from the weather.

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Video courtesy of iowadairyboys

Uses of Hay

Feeding hay to livestock is the number one use for hay.

Almost any animal on the farm – horses, cattle, sheep, goats, etc.- will eat hay. Hay is usually fed to livestock when they cannot graze or be in a pasture, either because it is winter or because of drought. Different animals have different nutritional requirements. Farmers carefully monitor what an animal is eating, to lớn make sure the animals are healthy. If xuất xắc spoils, it is not good to lớn feed khổng lồ animals, as rotten tuyệt can make livestock sick.

Interpreting a giỏi analysis & figuring out the amount of nutrients in giỏi is important for horse owners.

Interpreting a tốt analysis & figuring out the amount of nutrients in xuất xắc is important for horse owners.

The importance of testing your hay

Horses are naturally meant to lớn consume a diet based on forages. Pasture and hay should usually 3d the majority of the average horse"s diet. When it comes khổng lồ selecting hay, many people know that good-quality xuất xắc smells good, is soft, và has more leaves than stems. But how does this visual inspection match up with the actual amount of nutrients in the hay? How much crude protein or starch is in that bale of hay? to find out, you need to take a sample of hay & do a hay analysis.

A tốt analysis will reveal the specific amount of various nutrients that are found in the hay. These days, it is relatively simple khổng lồ obtain a xuất xắc analysis. Using a hay corer, collect samples from 10–20 percent of the bales in a single load (Figure 2). Do not combine loads of hay, even if they are different cuttings from the same field, or the same cutting from different years. Once a sample is collected and placed in a labeled bag, the sample is shipped off to a laboratory for analysis. The results are then sent back in a 1–2-page document.

 Figure 2. Taking a tuyệt sample. Photo credit: Danielle Smarsh.

Understanding the hay analysis can be tricky. The results are full of abbreviations và numbers và percents, and it can leave a person unsure what "good" and "bad" numbers are. So—let"s go through what these abbreviations mean, & what typical values we find for these nutrients.

One important chú ý before we begin: There are usually two different columns in a giỏi analysis that danh sách values for the nutrients. One will be titled "as is" or "as fed," while the other will be titled "DM." The column titled "as is" means the values listed are for the hay without any alterations; basically, the tuyệt as you would feed it lớn a horse. The column titled "DM," which stands for Dry Matter, means the values listed are for the tốt without water. In other words, the sample has been dried completely and there is no water in the sample. The DM column allows for easy comparison between different feedstuffs; for example, pasture & hay. It is far more accurate to compare the nutrients of pasture & hay once the water is removed. In the values listed for the nutrients below (with the exception of the moisture), the values are for DM.

Video: collecting a hay sample from a round bale.

Key nutrients and information listed on a tuyệt analysis

Moisture và Protein

Moisture:The ideal moisture for tốt is around 15 percent. If the moisture is less than 10 percent, the xuất xắc will be very dry & lose a lot of nutritious leaves khổng lồ shattering. The tuyệt will also not be palatable if it is very dry. If the moisture is greater than 18 percent, there is a risk for mold forming in the hay, and if the moisture is greater than 20 percent, there is a risk for spontaneous combustion.Crude Protein (CP): For adult horses, adequate protein should be provided by the hay if the CP value on the analysis is about 10–12 percent. If you have young horses, horses in high-intensity exercise, or broodmares that are lactating, you will want a higher CP percent in your forage. Also chú ý that the type of giỏi (grass versus legume) can impact the amount of CP; typically, legumes such as alfalfa will have higher CP as compared khổng lồ grass hays. But maturity of the plant when the hay was harvested will impact the CP. (This is why you are testing your hay—to know the true amount of nutrients in your hay!)


Carbohydrates fall into two categories: structural carbohydrates (fibers) and non-structural carbohydrates (sugars, starch, fructans, etc.). Both ADF and NDF give us an idea of the amount of fiber in the hay. Fiber is composed of structural carbohydrates found in plants (such as cellulose và hemicellulose). The more mature the plant, the higher amount of fiber it will contain. For horses that need to lose weight or are considered easy keepers, you may want ADF và NDF values khổng lồ be on the higher over of the ideal ranges presented below. For horses that require more calories like young growing horses or horses that are working hard, you may want lower ADF và NDF values.

Acid detergent fiber (ADF): This refers lớn cellulose & lignin. The ideal ADF for horses ranges from 30–45 percent. If you have values greater than 45 percent, your horse probably will not lượt thích it. ADF is negatively correlated with digestibility, so the higher the number, the less the giỏi will be broken down inside your horse"s gastrointestinal tract.Neutral detergent fiber (NDF):This refers to lớn cellulose, hemicellulose, and lignin. The ideal NDF ranges from 40–65 percent. If you have values greater than 65 percent, your horse probably will not eat it. NDF is negatively correlated with forage intake, so the higher the number, the less tuyệt your horse will eat.

The xuất xắc analysis will have measures of different types of non-structural carbohydrates (NSC). This will include any of the following: starch, water soluble carbohydrates (WSC), và ethanol soluble carbohydrates (ESC). Each of these will measure slightly different combinations of carbohydrates; for example, ESC measures simple sugars, mainly monosaccharides & disaccharides (like glucose & sucrose), while WSC measures simple sugars & fructans. As the name suggests, WSC dissolve in water, so a portion of it can be leached out of hay by soaking it to lớn reduce overall NSC.

There is not an ideal NSC number for all horses, but for horses who suffer from chronic laminitis or other metabolic disorders, it is recommended lớn keep NSC below 10–12 percent (on a DM basis). For horses that need to thua thảm weight, you may also want to lớn have lower NSC numbers. The xuất xắc analysis may not include NSC, but you can estimate it by adding together WSC + starch.


Digestible Energy (DE): This is the amount of energy that is digested và used by the horse. You can think of this as being similar to a "calorie count" of the feed. Depending on the energy needs of your horse, an ideal number will vary. The DE for most giỏi ranges from 0.75–1.0 Mcal/lb.

What else might be listed on a hay analysis?

The menu above is not everything that you might find on a tốt analysis. You can find out the amounts of many vitamins và minerals in your forage, which would be useful if you are balancing your horse"s diet or if your horse is ill & you are trying to lớn find out what the problem is. The analysis might also include values for ether extract fat, which is the amount of fat in a sample. Since forage is very low in fat, this number isn"t one we generally look closely at when analyzing hay. You might also see something called RFV, or relative feed value. This is generally used more for cattle nutrition but is an approximation of the unique of the hay. A value of 100 applies khổng lồ good-quality alfalfa hay. The higher the RFV, the better quality the xuất xắc for a ruminant’s digestive system. The forage testing lab may have several "levels" of analysis lớn choose from, và you can read what components are included in each package và select one based on your needs.

Remember—the ideal amount of certain nutrients will vary for each horse, và is impacted by factors such as health, activity/exercise level, age, and toàn thân condition score (Table 1). A young horse starting training will need xuất xắc that is higher in CP and DE, & lower in ADF và NDF. A middle-aged horse that is ridden once a week will probably need tốt lower in CP & DE, and higher ADF and NDF, as compared khổng lồ that younger horse. A horse suffering from laminitis will need NSC of less than 10–12 percent, while a horse that is healthy and at an ideal body toàn thân condition score does not need to have such a low percent of NSC.

TermWhat it MeansTypical Value
DMDry matter: the nutrients without water~85%
MoistureThe amount of water in the hay11-16%
CPCrude protein: amount of protein in the hay8-20%
ADFAcid detergent fiber (cellulose + lignin): a measurement of fiber30-45%
NDFNeutral detergent fiber (hemicellulose + cellulose + lignin): a measurement of fiber40-65%
NSCNon-structural carbohydrates: a measurement of simple sugars and starch. Subsets of this include WSC, ESC, và NFC.5-25+%
DEDigestible energy: amount of energy digested & used by the horse0.75-1.0 Mcal/lb


A tuyệt analysis provides a lot of useful information about your horse’s forage. This information is important in making sure your horse has a well-balanced diet. Remember that you should select tuyệt based on your horses’ needs; not every horse needs premium xuất xắc with tons of energy và protein. For horses that suffer from diseases such as chronic laminitis, equine metabolic syndrome, or obesity, a hay analysis is critical khổng lồ controlling the disease. If you are unsure how to balance your horse’s diet, work with an equine nutritionist.

Refer lớn your forage testing laboratory for directions on correctly taking a tốt sample. If you bởi vì not own a hay corer, liên hệ your local giamcanherbalthin.com office; they may have one you can borrow, or can send someone lớn your farm to help with sample collection. A danh mục of certified forage testing laboratories is located at the National Forage Testing Association website.