Photo by Sue Weaver
Pigs are the most likely farm animal to vomit because a lot of diseases will make them do so. Luckily, our pig, Carlotta, is healthy in this picture!
My question this week is a good one: Can farm animals vomit? That is, can they really vomit—not eject stomach contents at will, like llamas and alpacas can do, or dribble throat contents if we choke.
The answer is: It depends! Most of us can throw up under certain circumstances, but horses and other equines can't.
Vomiting shouldn't be confused with regurgitation. Vomiting means the stuff in our stomach is ejected through the mouth, while regurgitation happens when food is swallowed but doesn't reach the stomach before coming back up. Cudding is another form of regurgitation, whereby ruminants—like us goats, sheep and cattle—hork up a bolus of pre-chewed food and chew it again to extract more nutrients. We regurgitate as part of cudding all the time but usually only vomit if we've been accidentally poisoned, so vomiting is a serious issue for us. If you see your goat, sheep, or cow throwing up, call your veterinarian without delay!
All mammals have a strong band of muscle around their esophagus right at the entrance to their stomach. To vomit, that muscle has to relax. In equines, this muscle, called the “cardiac sphincter” or “esophageal sphincter” is so strong and rigid that the animal's stomach lining usually ruptures before the cardiac sphincter gives way. Because of this structure's strength and inability to relax, food can go in only one direction—down—so equines never throw up.
Pigs are the most likely farm animals to truly vomit. In fact, a pig vomiting is a symptom of several swine diseases:
Hemagglutinating Encephalomyelitis (HEV)
This disease occurs in 4- to 14-day-old piglets. It's a systemic (all over the body) disease of the nervous system that causes vomiting, lethargy, huddling, grinding of teeth due to pain, constipation and convulsions in the poor pig.
Also called porcine epidemic diarrhea, this is another swine disease that causes considerable vomiting. Pigs of all ages get it, but it's more severe with piglets. Besides vomiting, young pigs sick with porcine epidemic diarrhea lose their appetites and have a lot of watery diarrhea for a day to a week or more; older pigs have the same symptoms but to a lesser degree.
Hogs suffering from pseudorabies sometimes vomit, as do pigs with other serious diseases, such as hog cholera and African swine fever.
Other Reasons Pigs Vomit
Pigs of all ages are also acutely sensitive to a type of mycotoxin called vomitoxin, sometimes found in corn, which causes vomiting, anemia, diarrhea and slower growth rate. Suckling pigs are prone to threadworm infestation and this causes vomiting, too. So can gastric ulcers, hairballs and swallowing bad things, like stones and chunks of metal.
And, just like us goats and my other ruminant friends, pigs vomit if they eat poisonous things, among them inorganic arsenicals (ant bait, insecticides and pesticides), cadmium (paint, solder, corrosion on old batteries), flourine (from water or forage contaminated with industrial waste), ethylene glycol (antifreeze), large overdoses of wormers like levamisole and piperazine, and a whole host of poisonous plants!
Do you have a livestock or wildlife question you want me to answer? Send me your question!
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