Horses are capable of self-regulating their intake when given the chance. If they are only offered a set amount of hay at a time, they will likely eat it very quickly and will be anxious for more. But if given all they want, they will overeat at first (for a week or less) and then, once they see that they can walk away and relax and the hay will still be there when they return, they will calm down and eat only what they need to maintain a healthy weight. Pasture and/or hay offered free choice will affect how your horse behaves. The more you treat your horse like a horse in the wild, the calmer and more cooperative he will be. He needs to graze continuously, and he also needs to be able to interact with other horses. Negative behaviors such as cribbing, pawing, and irritability are often alleviated by feeding more hay and providing turnout with his buddies.
Great Information on what your horse truely needs!  Thanks Dr. Getty, for packing an encyclopedia of information into one handy, easy to read book.

Winter Care for Horses by Dr Peggy Awerda,
Dept of Animal Science, Iowa State University         December 2, 2011

A horse's adaptation to cold weather is either acute (immediate) or chronic (long-term).The immediate response of a horse to a sudden change in temperature is to change its behavior. Horses seek shelter from the cold and wind, or huddle together, to decrease heat loss. Horses will stand with their heads away from the wind, their tails set low and into the wind. Horses stop foraging and stop moving to conserve energy. On the other hand it is not unusual to see horses running in cold weather, which increases muscle contraction causing heat production. Shivering and other voluntary muscular activity can also generate substantial body heat. For chronic exposure, horses require 10-21 days to acclimatize to the cold. Horses develop a heavy winter hair coat. The coat acts as a tremendous insulator. Cold weather will cause the hair to stand up (piloerection), trapping and retaining body heat.

Equine Ulcers...For Life?

by: Janice L. Holland, PhD, PAS Research printed in The Horse.com Magazine
What could the following three situations all have in common?
You return home from a horse show after a disappointing weekend. Your elite performance horse, usually high in the ribbons, did not place well. He occasionally looks at his sides and appears uncomfortable.
You have a young, excitable filly that was recently weaned. A normally robust and outgoing foal, she is now standing in her stall, uninterested in either interacting with humans or eating her grain.
Your mature gelding that lives on lush pasture recently went through a mild bout of laminitis. He's always been a stoic fellow and rarely shows when he's in pain. Now, his hair coat is dull, and he seems to be "depressed."
What might be surprising to some is that while these clinical signs could point to a number of problems, all three of these horses could be diagnosed with the same condition: equine gastric ulcer syndrome.
History and Signs
Equine gastric ulcer syndrome includes not only ulcers found within the stomach (usually in the esophageal region, or upper portion), but also ulcers found at the duodenal part of the small intestine, which is the portion closest to the stomach. Ulcers occur when the pH of these gastrointestinal tract areas becomes too acidic, and cells of the lining are damaged. The primary acid of digestion in the stomach, hydrochloric acid, is produced and released continuously into the stomach of the horse, unlike in humans, where it is produced only when food is present. Horses produce almost 1.5 liters/hour of this acid because they have evolved as continuous eaters, or grazers.
Ulcers can occur in horses of all disciplines and management situations, although horses in higher stress environments do appear to be more susceptible, according to veterinarians and researchers. A variety of studies have been conducted on gastric ulcer incidence in horses competing or training in different disciplines; some of these results are shown in the chart on the following page.
A definitive diagnosis can only be made by a veterinarian who performs gastroscopy on the horse. This involves placing an endoscope (a tubular optical instrument)into the stomach of the sedated horse to view the stomach lining. However, there are some signs that a horse owner or farm manager can watch for that might be indicative of a horse experiencing gastric ulceration. Some of these, on their own, might not indicate a problem, but owners should be concerned when they observe more than one at a time.
Foals suffering from gastric ulcers, for instance, might show poor appetite (anorexia), bruxism (teeth grinding), excessive salivation, diarrhea, and lying on their back (to relieve some of the pain). Mature horses might show some of the same signs, such as anorexia, but they might also exhibit weight loss/poor body condition, a dull or rough hair coat, an attitude or behavior change (especially toward training), poor or decreased performance, a tendency to lie down, and mild, chronic, or intermittent colic (Buchanan and Andrews, 2003).
Causative Factors
There are a variety of factors that can predispose a horse to ulcers. Some can be managed, while others, such as genetic predisposition, are more difficult or impossible to control. The three most commonly mentioned causes of gastric ulcers are summarized below.
The feeding regimen, including type of feed offered and how often, is one of the most common factors related to ulcer incidence (Reese and Andrews, 2009). Horses that are fed only a few meals a day, with grain or concentrate feeds that are high in soluble carbohydrates and comprise a large percentage of their diet, are most susceptible. Since the stomach empties fairly quickly after a meal, usually within 30-60 minutes, the cells lining the stomach can be exposed to the acids that are secreted for several hours before the next meal. So, horses that graze continuously or that are fed free-choice hay tend to have a lower ulcer incidence. Feeding grains such as corn, barley, oats, and wheat products might also contribute to a higher ulcer incidence, related to increased levels of a hormone called gastrin that stimulates stomach acid production.
Training and exercise might also contribute to an increased incidence of gastric ulcers. Horses involved in strenuous exercise have a higher incidence of gastric lesions, as shown in the table below, and intense exercise might cause a serum gastrin increase similar to that observed in horses consuming high-grain diets.
Decreased blood flow to the stomach during exercise, as well as increased abdominal pressure, might also be a cause (Orsini et al., 2009). Studies have shown that external pressure on the stomach during exercise forces the liquid contents of the lower portion of the stomach upward, exposing the sensitive mucosa of the gastric wall to the stomach acids and inducing ulcerous lesions. Another training factor that might contribute to ulcers is increasing the physical demands on the horse too rapidly. This might lead to an increased physiologic stress level, which can in turn increase acid production, and decreased mucosal blood flow, which can delay gastric emptying.
Stall confinement in performance horses could be a contributing factor as well, but ulcers might be more related to a horse's feeding schedule than confinement alone. A study conducted in New Zealand (Bell et al., 2007) found that racehorses that spent part of the day on pasture had the same incidence of ulcers (89%) as stall-confined racehorses.
Some medications are also recognized as causing ulceration. According to a 2009 study by Ricardo Videla, DVM, and Frank M. Andrews, DVM, MS, Dipl. ACVIM, the most common group of medications implicated are non-steroidal anti-inflammatory drugs (NSAIDs), which can impair mucosal blood flow and also compromise the mucus-bicarbonate barrier of the stomach, a layer which generally would protect the stomach lining from the acid. The two most common NSAIDs used in horses are phenylbutazone (Bute) and flunixin meglumine (Banamine). The potential to cause ulceration is why these medications often are only given for a few days and then discontinued.
Treatment
There are a variety of medications that can be given to treat ulcers. Some are available at the local feed store or in horse supply catalogs, while others are only available through a veterinarian.Histamine antagonists (H2 blockers), such as cimetidine and ranitidine, block hydrochloric acid secretion. Proton pump inhibitors (PPIs) such as omeprazole (Gastrogard) also prevent hydrochloric acid secretion and are longer-acting than the H2 blockers. Anthony Blikslager, DVM, PhD, Dipl. ACVS, professor of equine surgery and gastroenterology in North Carolina State University's Department of Clinical Sciences, recommends omeprazole as the best therapy for ulcers in horses. PPIs are very efficient at increasing the pH (decreasing the acid level) in the stomach but he says that it takes about three days for these to have the maximal effect of blocking the acid pump. Many veterinarians will recommend giving one of the H2 blockers concurrently with the PPI for the first few days because, although they do not decrease acid to the same extent, they will act more rapidly and can block secretion until the PPI takes full effect.
Veterinarians sometimes recommend antacids, which contain magnesium hydroxide or aluminum hydroxide. According to a study by CK Clark et al., these treatments can cause rapid increase in pH and might eliminate some clinical signs quickly. However, most of these medications only provide relief for a few hours.
Protectants such as sucralfate might be useful in combination with other therapies. These medications form a gel within the stomach that coats and binds to the surface of the ulcers and promotes healing. Blikslager believes sucralfate can be a useful "third line" of treatment in combination with PPIs and H2 blockers, depending on the severity of the ulcers.
Foods that are high in amino acids L-glutamine and L-threonine, such as green cabbage, might also aid in gastric ulcer treatment and prevention, suggest some researchers. These amino acids help repair and nourish the cells lining the stomach and intestines (Hagen et al., 2009).
While manufacturers of several natural treatments such as aloe vera juice and papaya claim to help treat ulcers, Blikslager cautions that these alternative therapies have not been examined in clinical studies of horses, so their effectiveness has not been proven.
Changing the Diet
Diet modification also is recommended for horses that are predisposed to gastric ulcers. Diets that are higher in forage content and lower in grain should promote the appropriate pH within the stomach and small intestine. In addition, having small amounts of feed present in the stomach for most hours of the day, mimicking the natural feeding tendencies of the horse, can help buffer the acid. According to Blikslager, forage in the diet also essentially traps the acid in the lower portion of the stomach, thus protecting the upper regions that are more prone to ulceration.
Horses that require more calories than can be provided by forage alone--such as competition horses with high daily energy requirements--might need a diet with higher fat content. As well as decreasing the acidity in the stomach, some oils, such as oat oil and rice bran oil, contain polar lipids, which are water-soluble fats that help transport nutrients into the bloodstream and support a healthy gut lining (Frank et al., 2005). Due to its high calcium content, alfalfa might provide an effect similar to antacids (Lybbert et al., 2007).
Prevention
Ideally horses would be kept in a management situation where ulcers are not even a remote possibility, because ulcers are essentially a management disease. However, the reality is that even horses maintained under the most idyllic conditions can develop ulcers. For example, in a 2007 study (TheHorse.com/9950) Sarah le Jeune, DVM, Dipl. ACVS, ECVS, and colleagues evaluated ulcer incidence in 62 Thoroughbred broodmares that were kept on pasture. More than 70% of the mares, both pregnant and open (not in foal), had ulcers, and no one factor was isolated as causing the problem.
Some of the suggestions given to treat horses with ulcerscan also be used to prevent ulcers from recurring, or even occurring in the first place. According to Blikslager, the best thing a manager can do to prevent ulcers is to provide maximal pasture turnout and develop/offer a forage-based diet. He also recommends dividing the horse's diet into multiple small meals throughout the day. For horses that must be confined to stalls for large portions of the day, Blikslager advises using the newer hay nets available that have smaller holes. The horses cannot eat all the hay at one time and will essentially "graze" all day while trying to get the hay out of the nets. He also recommends decreasing the stress of training or competition (e.g., providing a horse with ample time to adapt to a new environment and scheduling rest or downtime between periods of heavy training). If this is not possible, then your horse might require some of the medications mentioned in the treatment section.
Take-Home Message
Some horses are more predisposed to getting gastric ulcers, due to management, performance, or temperament. Nonetheless, horses can be managed, even in less-than-ideal conditions, to lessen the incidence. With proper medical treatment and removal of predisposing factors, ulcers can be healed, and horses can remain ulcer-free. However, ulcers will reoccur if diet, exercise, and management changes are not incorporated.
Horse owners and managers should use caution in deciding what methods to use to manage and/or prevent ulcers. As with all disorders, consult a veterinarian or equine nutritionist about syndromes that might be caused by diet or management.
Research printed in The Horse.com Magazine

Horses' Behavior and Welfare Negatively Impacted by Low-Fiber Diets
by: Stacey Oke, DVM, MSc     November 16 2010, Article # 17255  - The Horse On-line Magazine
Despite the fact that horses evolved on a forage-based diet that is high in fiber and low in calories, some horse owners and trainers just can't resist feeding a low-fiber, calorie-dense diet.
"Horses are grazing animals," explains Katherine A. Houpt, VMD, PhD, Dipl. ACVB, a professor emeritus of Cornell University's College of Veterinary Medicine. "When they are denied access to pasture to partake in this natural activity, health and behavior issues arise, like the development of gastric ulcers and destruction of wood fences and stall walls."
To determine if horses' welfare, in addition to their health, was compromised when denied fiber, Houpt and co-author Jaime Elia assessed the "motivation for fiber" of eight mares fed two different diets, either orchard grass hay ad libitum or a complete pelleted feed, for three weeks. The horses were also trained to press a panel to obtain a food reward.
"We found that when horses were fed pellets, they worked harder to obtain a hay food reward than when they were fed hay," said Houpt.
In addition, the researchers also found that:
Horses fed hay spent 61.5% of their time (throughout a 24-hour period) eating, while horses fed pellets spent only 10% of their time eating
Horses fed pellets spent 58% of their time standing while horses fed hay spent 37% of their time standing, and
Horses fed pellets spent 11.5% of the their time sifting through the bedding of their stall looking for food whereas horses fed hay only spent 1.2% of their time practicing this "searching behavior."
According to Houpt, "These findings clearly show that horses were motivated to work for hay when they were fed a pelleted diet, but not when they were fed a hay diet. That is, these horses showed a 'hunger for hay' when fed a pelleted diet."
The authors concluded that a reduction in dietary fiber has a major impact on the behavior and physiology of horses. They recommend feeding at least half a bale of first cutting hay per day, or offering free choice hay.
The study, "Motivation for hay: Effects of a pelleted diet on behavior and physiology of horses," is scheduled to be published in an upcoming edition of the journal Physiology & Behavior. The abstract is currently available on PubMed.

Feed Management May Influence Behavior Including Stereotypes
Kentucky Equine Research, December 24, 2010 
In many cases, feeding practices for today’s horses are quite different from the eating patterns found among wild horses. The effects of feed types and feed management have been studied to determine the effects, if any, of modern feeding practices on equine behavior.
A natural pattern of unlimited grazing provides horses with exercise, social contact, hours of chewing, high saliva production, a relatively steady supply of ingested material entering the stomach, and only moderate fluctuations in blood glucose and insulin. Stalled horses eating large grain meals may meet their caloric requirement, but their other physiologic needs may be thrown into turmoil.
Studies show that behaviors such as coprophagy (eating manure), stall-chewing, and eating of straw bedding are less common in stalled horses that are given large amounts of hay and more common in stalled horses given an all-concentrate diet. Research has pointed out that horses eating large grain meals have significant fluctuations in plasma glucose and insulin, possibly causing peaks and troughs in energy that may be seen as nervous, unpredictable behavior. They may also be subject to digestive and metabolic disorders like hindgut acidosis, colic, and gastric ulceration.
While an all-forage diet might be the most natural, many heavily exercised horses are not able to consume enough calories from hay or grass to fuel the demands of training and performance. Replacement of some dietary carbohydrates with fiber and fat is helpful in avoiding glycemic and insulinemic fluctuations, thereby leveling out peaks and slumps in energy. The addition of oil leads to slower gastric emptying so horses may feel full longer, reducing stress caused by the urge to graze. Various studies have shown a tendency toward a decline in aggressive behavior, less reactivity to sudden visual stimulation (such as opening an umbrella), and less moving around and startled reaction to loud noises or invasion of space (pressure) in horses eating diets with more fat, more hay, and/or lower levels of carbohydrates.
Weaning is a stressful time for young horses, and the same trends (less stress, lower levels of cortisol, reduced reactivity to novel visual stimuli) were seen in weanlings fed a diet higher in fat and fiber. These weanlings also spent more time investigating novel objects and completed a handling test more quickly than foals fed traditional diets high in starch and sugar. A recent study on insulin resistance suggested that over long periods of time, fat and fiber diets may facilitate better patterns of glucose regulation resulting in an effect on brain function, specifically more efficient production of the mood regulator serotonin. This effect was seen in foals fed a fat and fiber diet.
There is also some evidence that pregnant mare diets may influence insulin sensitivity in their offspring. Up to 80 days of age, foals born to mares fed starch and sugar diets tended to have higher levels of glucose and insulin than those whose dams ate a fat and fiber diet during late pregnancy. Foals of mares fed the starch and sugar diet also tended to have lower insulin sensitivity at 160 days of age, even though all mares were fed the fat and fiber diet after the foals were born.
Supplementation with tryptophan has been shown to increase alertness and attention in humans, and tryptophan depletion causes anxious behavior in rats. Tryptophan supplements are marketed as calming aids for horses in spite of the fact that there is no evidence that a calming effect is seen in equines. There is some evidence that various herbal preparations may calm excitable horses, but the active ingredients of herbal preparations may be somewhat unpredictable, making it difficult to be certain of their effect on behavior.
Oral stereotypies such as cribbing and locomotor stereotypies such as weaving may be related to feeding practices and/or digestive function. Some studies have shown that cribbing, which is not seen in populations of wild or feral horses, rises in intensity during the hour before feeding of stalled horses, and peaks four to eight hours after feeding. Research has shown that weaving is most common right before food delivery. Dividing the daily ration into multiple feedings reduced the overall incidence of cribbing but increased the incidence of weaving. Any factor that reduces the stress of barn confinement, especially providing increased visual access to other horses, tends to reduce the incidence of weaving.
Environmental enrichment has little or no effect on cribbing; this behavior seems to be increased by a low-forage or high-grain diet and decreased somewhat when horses are bedded on straw, possibly because straw provides another edible fiber source. The precise relationship between cribbing and gastrointestinal discomfort has not been established. Large grain meals increase the risk of colic and have been shown to alter the pH of the gastrointestinal tract.
Foals that crib show significantly greater evidence of gastric inflammation and early ulceration than those of normal foals. Feeding an antacid reduces inflammation and ulceration and tends to result in a reduction in cribbing behavior. Also, cribbing leads to the production of small amounts of saliva, a buffer of acid in the stomach. The stress of weaning is both psychological and physical. The weanling is deprived of milk which has been a component of its daily diet, and few foals make an immediate and smooth transfer to eating grain. Even brief periods of not eating can lead to acidity, ulceration, and an increased risk for some types of colic. However, not all foals develop digestive problems or stereotypies. In one study, 42 of 186 foals—slightly fewer than one in four—began to show wood-chewing, cribbing, or both after weaning.
In general, the best practice for avoiding or minimizing problems involves keeping a horse’s environment and feed management practices as close as possible to those of horses living in natural conditions.