Magesekk

The stomach is a muscular pouch that takes over once food leaves the esophagus, mixing it with acid and enzymes while churning it into a semi-liquid consistency the intestine can process. It also acts as a holding tank, releasing its contents into the small intestine gradually rather than all at once, which is why a meal can sit there for a couple of hours before digestion downstream even begins.

A tough mucus layer protects the stomach's own lining from the acid it produces, and when that protection breaks down, irritation or ulceration follows. Stomach function looks different across species: true monogastric stomachs in dogs, cats, and pigs work much like each other, ruminants use their stomach's final chamber for acid digestion only after fermentation earlier in the tract, and birds split the job between two separate chambers. Because the stomach sits early in digestion, problems here tend to show up quickly as vomiting or discomfort, often sooner than problems further down the tract.

The stomach has four functional regions: the cardia where the esophagus enters, the fundus and body that form the main storage area, and the antrum and pylorus that grind food and control its release into the small intestine through a muscular valve. Specialized cells in the stomach lining produce acid, enzymes, and protective mucus, all under close hormonal and nervous control.

Species differences here are substantial. Cattle, sheep, and goats have three forestomach chambers, the rumen, reticulum, and omasum, that ferment plant fiber before food reaches the abomasum, their true, acid-producing stomach. Horses have a small stomach relative to their body size and a very strong sphincter at the esophageal junction, which is why they physically cannot vomit under normal circumstances. Birds process food through a glandular proventriculus that adds acid and enzymes, followed by a muscular gizzard that grinds food, often with the help of small stones or grit the bird has swallowed. Dogs, cats, and pigs have a single-chambered stomach broadly similar in layout and function.

Gastritis, general inflammation of the stomach lining, is common across species and often follows dietary indiscretion, a sudden food change, or certain medications. Gastric ulcers are a particular concern in horses, where they turn up extremely often in performance and stall-kept animals, and they also occur in dogs under some drug treatments or, less frequently, in cats.

Gastric dilatation and volvulus, often shortened to GDV or bloat, is a life-threatening emergency seen mainly in large, deep-chested dog breeds, where the stomach fills with gas and can twist on itself, cutting off blood supply. Foreign body obstruction happens when a swallowed object lodges at the pylorus or blocks the stomach outlet, and it affects curious animals of any species that will mouth or swallow non-food items. Older pets across species can develop gastric tumors, and some animals develop delayed gastric emptying, where the stomach struggles to move food along at a normal pace, leading to vomiting of undigested food well after a meal.

Vomiting is the hallmark stomach sign, and its timing offers clues. Vomiting food that still looks mostly undigested several hours after a meal suggests the stomach is not emptying properly, while vomiting shortly after eating points more toward simple overeating or gastritis. Retching without producing much, along with drooling and repeated swallowing, usually signals nausea building before a vomiting episode.

Watch also for reduced interest in food followed by apparent hunger soon after, restlessness or pacing, and a visibly swollen or tight abdomen, which in a large dog breed warrants urgent attention given the risk of bloat. Horses with stomach discomfort often grind their teeth, a behavior called bruxism, and may show subtle signs like reduced performance or mild colic rather than obvious vomiting, since they cannot vomit at all. Any pet that seems hungry but then hesitates or acts uncomfortable while eating is worth watching closely over the following day.

A single vomiting episode in a pet that otherwise acts normal and keeps food down afterward is reasonable to monitor at home. Occasional vomiting of a hairball in cats, for instance, is not usually cause for alarm on its own, and it rarely needs anything beyond watching how the pet does over the next meal or two.

Arrange a same-day visit if vomiting repeats several times in a day, if the pet cannot keep any food or water down, or if a horse shows ongoing discomfort after eating. Treat it as an emergency if you see nonproductive retching paired with a visibly distended, tight abdomen, especially in a large or deep-chested dog, since this pattern is consistent with GDV and can turn fatal within hours. Sudden collapse, pale gums, or a horse repeatedly lying down and getting up while looking at its flank also need immediate veterinary attention rather than a wait-and-see approach, since both scenarios can deteriorate quickly once true pain sets in.

Why does my dog vomit undigested food hours after eating?

This pattern usually points to slow or delayed stomach emptying rather than a problem with the food itself. Occasional episodes are often not serious, but a pattern that repeats over several days should be checked, since causes range from eating too fast to something requiring diagnostic imaging.

What is bloat and why is it so dangerous?

Bloat, or gastric dilatation and volvulus, happens when the stomach fills with gas and then twists on its own axis, trapping the gas and cutting off blood supply to the stomach and sometimes the spleen. It progresses within hours and is fatal without emergency surgery, which is why large, deep-chested dogs showing a swollen abdomen and unproductive retching need immediate veterinary care.

Do horses get stomach ulcers often?

Yes, gastric ulcers are widely recognized as common in horses, particularly those in intense training or kept with limited turnout and forage access. Signs can be subtle, including reduced appetite, mild weight loss, or changes in attitude under saddle, rather than obvious pain.

Can cats get stomach ulcers?

It happens, but less often than in horses or dogs, and it is usually linked to an underlying illness, certain medications, or in rare cases a tumor rather than occurring on its own. A cat with ongoing vomiting or reduced appetite should be evaluated rather than assumed to have a simple ulcer.

Why can't horses vomit?

Horses have a very strong muscular valve where the esophagus meets the stomach, along with an esophagus that enters at a sharp angle, and together these make vomiting essentially impossible under normal circumstances. This is part of why colic, abdominal pain without vomiting, is taken so seriously in horses; the usual relief valve simply is not available to them.