Editing Hay (section)

== Use ==
{{Main|Equine nutrition|Cattle feeding|Sheep husbandry}}
[[file:HorsesAndHay.jpg|thumb|Horses eating hay]]
{{see also|Fodder|Ruminant|Cecum}}

Hay or grass is the foundation of the diet for all grazing animals, and can provide as much as 100% of the [[fodder]] required for an animal. Hay is usually fed to an animal during times when winter, drought, or other conditions make [[pasture]] unavailable. Animals that can eat hay vary in the types of grasses suitable for consumption, the ways they consume hay, and how they digest it. Therefore, different types of animals require hay that consists of similar plants to what they would eat while grazing, and, likewise, plants that are toxic to an animal in pasture are generally also toxic if they are dried into hay.

Most animals are fed hay in two daily feedings, morning and evening, more for the convenience of humans, as most grazing animals on pasture naturally consume [[fodder]] in multiple feedings throughout the day. Some animals, especially those being raised for meat, may be given enough hay that they simply are able to eat all day. Other animals, especially those that are ridden or driven as [[working animal]]s may be given a more limited amount of hay to prevent them from getting too fat. The proper amount of hay and the type of hay required varies somewhat between different species. <!-- and is too complex to fully explain here, hence the "main" tags, add more if needed--> Some animals are also fed concentrated feeds such as [[grain]] or vitamin supplements in addition to hay. In most cases, hay or pasture [[forage]] must make up 50% or more of the diet by weight.

One of the most significant differences in hay digestion is between [[ruminant]] animals, such as [[cattle]] and [[sheep]], and nonruminant, [[hindgut fermentation|hindgut fermentors]], such as [[horse]]s. Both types of animals can digest [[cellulose]] in grass and hay, but do so by different mechanisms. Because of the four-chambered stomach of cattle, they are often able to break down older forage and have more tolerance of mold and changes in diet. <!--please verify this statement, I am over-generalizing, I know--> The single-chambered stomach and [[cecum]] or "hindgut" of the horse uses bacterial processes to break down cellulose that are more sensitive to changes in feeds and the presence of mold or other toxins, requiring horses to be fed hay of a more consistent type and quality.<ref>{{cite web |url=http://www.agry.purdue.edu/Ext/forages/publications/ID-190.htm |title=Selecting Hay for Horses |publisher=Agry.purdue.edu |date=1914-06-30 |access-date=2012-02-23 |archive-date=2011-03-09 |archive-url=https://web.archive.org/web/20110309114014/http://www.agry.purdue.edu/ext/forages/publications/ID-190.htm |url-status=dead }}</ref>

[[File:George Stubbs - Haymaking - WGA21948.jpg|thumb|''[[Haymakers (painting)|Haymakers]]'' by [[George Stubbs]], 1785]]
Different animals also use hay in different ways: cattle evolved to eat forages in relatively large quantities at a single feeding, and then, due to the process of [[ruminant|rumination]], take a considerable amount of time for their stomachs to digest food, often accomplished while the animal is lying down, at rest. Thus quantity of hay is important for cattle, who can effectively digest hay of low quality if fed in sufficient amounts. <!--hope that is accurate, fix if it is not--><!-- someone also please add how much hay cattle can eat in a day (i.e. compared to how horses can consume 2.5% of their weight per day)--> Sheep will eat between two and four percent of their body weight per day in dry feed, such as hay,<ref>{{cite web|url=http://www.sheepandgoat.com/articles/feedingsmallruminants.html |last=Schoenian |first=Susan |title=An Introduction to Feeding Small Ruminants |work=Western Maryland Research & Education Center |publisher=Maryland Cooperative Extension Service |access-date=2007-11-12}}</ref> and are very efficient at obtaining the most nutrition possible from three to five pounds per day of hay or other forage.<ref>{{cite web|url=http://www.ext.vt.edu/pubs/sheep/410-853/410-853.html|title=Information on Feeding sheep|url-status=dead|archive-url=https://web.archive.org/web/20071114183337/http://www.ext.vt.edu/pubs/sheep/410-853/410-853.html|archive-date=2007-11-14}}</ref> They require three to four hours per day to eat enough hay to meet their nutritional requirements.<ref>{{cite web |url=http://ag.ansc.purdue.edu/sheep/articles/strchhay.html |author=Mike Neary and Keith Johnson |title=Stretching Hay Supplies |work=Indiana Sheep Tales Vol. 2 |year=1991 |publisher=Purdue University |access-date=2007-11-12 |url-status=dead |archive-url=https://web.archive.org/web/20071012221311/http://ag.ansc.purdue.edu/sheep/articles/strchhay.html |archive-date=2007-10-12 }}</ref>

Unlike ruminants, horses digest their food in small portions throughout the day and can utilize only about 2.5% of their body weight in feed within a 24-hour period. Horses evolved to graze continuously while on the move, covering up to 50 miles (80&nbsp;km) per day in the wild. Their stomachs digest food quickly, allowing them to extract a higher nutritional value from smaller quantities of feed<ref>{{cite book |last=Budiansky |first=Stephen |title=The Nature of Horses |publisher=Free Press |year=1997 |isbn=0-684-82768-9 |url-access=registration |url=https://archive.org/details/natureofhorsesex00budi }}</ref> When horses are fed low-quality hay, they may develop an unhealthy, obese, "hay belly" due to over-consumption of "empty" calories. If their type of feed is changed dramatically, or if they are fed moldy hay or hay containing toxic plants, they can become ill; [[horse colic|colic]] is the leading cause of death in horses. Contaminated hay can also lead to respiratory problems in horses. Hay can be soaked in water, sprinkled with water or subjected to [[Hay steaming|steaming]] to reduce dust.