Gastroduodenal Ulcers (GDU) in Foals
Your foal is a winner—you could tell it the minute he was born. He got up on his legs right away, had no trouble nursing and has been trouble-free these past two months. But recently, he seems different; a little out of sorts. He spends more time lying down and his coat has gone dull. He’s not nursing as often or as long as he did, and he’s stopped gaining weight: he may even have lost a little. You think about calling the vet, but there doesn’t seem to be anything major going on, so you decide to wait and see.
The problem with the ‘wait and see’ approach is that your foal may be showing signs of gastroduodenal ulcers; lesions or wounds in the lining of the stomach. (Ulcers can also be found in the esophagus, and lower intestines, but in young foals they are most common in the stomach.) The bigger problem with ‘wait and see’ is that by the time ulcer symptoms become pronounced, it may be too late. Once an ulcer perforates, (deepens to the point that there is a hole in the tissue), you risk leakage, infection and hemorrhage. In cases of perforated ulcer, the chances of saving the foal, even with surgery, are slim.
Ulcers are surprisingly common in foals (and even more common in adult horses), but they often don’t make the news because, in foals, most of them are asymptomatic; the animal shows no signs of being ill. Foals are very rarely diagnosed with ulcers at birth, but in the first 30 days after delivery, many foals will develop ulcers in the top portion of the stomach (called the saccus cecus), where it meets the lower portion of the stomach at a boundary called the margo plicata. In most foals—some experts say close to 80%--the cells in the stomach lining die around the 35th day of life and are replaced, in a process called desquamation, or “shedding”. Ulcers form in the margo plicata, but manage to heal without any trouble to the animal. Foals may experience mild diarrhea and brief appetite loss, but then recover.
In foals more than 30 days old, symptomatic ulcers (as the one described in the opening paragraph) require attention and action. In addition to seeming unhappy or depressed, foals may brux (grind their teeth), roll or lie down, salivate and lose condition in an extremely short period of time. Their tongues may be coated in grey or white; a sign of dehydration, and they stop nursing the way they should. (Foals usually nurse up to seventy times a day: interrupted nursing is another indication of discomfort.) Symptomatic ulcers usually occur in the lower portion of the stomach or the small intestine.
If your foal is showing signs of dehydration, drooling, diarrhea, or pain (marked by rolling, bruxism, recumbency and an anxious or irritable attitude), don’t hesitate: call the vet. While ulcers can be treated and cured, they can quickly worsen and perforate when left untreated.
Ulcers Due to Other Conditions
Like any wound, ulcers may heal unevenly, leaving scar tissue that in itself becomes a problem because it obstructs necessary openings in the body. Foals sometimes develop ulcers secondary to earlier ulcers that healed leaving behind adhesions, or “strictures”. In strictures, the healed ulcer may have created a blockage interrupting normal stomach functioning, so that stomach acids aren’t moving the way they should through the body, causing further ulceration. These new ulcers often occur in the duodenum, in the small intestine, and become apparent when the foal is 3-5 months old. Symptoms include signs of pain, anorexia, tongue sucking, and dehydration. A veterinary exam may show electrolyte imbalances.
If a veterinarian determines that a stricture is causing the ulcers, the ulcers can be treated, but the stricture must also be addressed. Surgery is needed to correct the problem.
What Causes Ulcers?
In humans, most ulcers are caused by a bacterium, but in horses, ulcers seem to occur in relation to stress and issues related to feeding. Horses’ stomachs secrete digestive juices 24 hours a day: in nature, constant grazing keeps the stomach acid levels down. But in situations where horses are fed at intervals, or as in the case of foals who are sometimes separated from their dams while nursing, the constant production of stomach acids overwhelm the natural protection system of the cells in the stomach and intestine, damaging cells and creating lesions. Stress, such as that associated with traveling, weaning schedules, overcrowding or medical procedures seems to contribute to the imbalance between acid production and the natural buffering of the stomach cells. Non-steroidal Anti-inflammatory Drugs (NSAIDS) have been shown to create ulcers in horses, and many vets use additional medications to prevent ulcers when horses are on NSAIDs.
Detecting Ulcers
Your vet may use noted signs, palpation, general examinations and high-tech medical tools like endoscopes or contrast radiography to diagnose ulcers and, after treatment, to be sure that they have healed.
How Are Ulcers Cured?
Unless there’s a physical blockage needing correction through surgery, ulcers are usually cured by a course of medication. There are four types of medicines used to cure ulcers in horses, and some of them may be used in combination with others. The most commonly used drugs are named after each description.
1. Antacids. Drugs that interact with stomach acid and neutralize it, preventing further irritation. (Magnesium hydroxide, aluminum hydroxide, and calcium carbonate, singly or in combination.)
2. Histamine (H2) Receptor Antagonists. Drugs that bind to the histamine receptors in the cells, blocking the stimulation of acid secretion. (Cimetidine, Ranatidine.)
3. Proton pump inhibitor: Suppresses the enzyme responsible for the secretion of gastric acids. (Omeprazole.)
4. Cytoprotective Drugs. These drugs bind with the ulcer itself, creating another covering, like a chemical Band-Aid, that helps shield the ulcer from further damage and promote healing. (Sucralfate.)
How Can I Prevent Ulcers in My Foals?
As you’ve seen, some foals will develop ulcers as part of their normal development: ideally, in young foals, the ulcers heal themselves before manifesting in any sign of illness. But to do your part in preventing ulcers, pay attention to your foal’s feeding schedule, feed type and environmental stressors.
- Allow unweaned foals free access to their dams, and to hay or pasture as well; feeding on hay provides a natural buffer to stomach acids.
- Watch foals prone to colic: they may also develop ulcers.
- Make weaning as easy as possible, to limit anorexia and stress. (See our article on weaning.)
- Make any feeding changes slowly, over a period of days, so your foal’s gastrointestinal system has the chance to adjust to the new chemical makeup of the feed.
- Limit stressors: like all of us, horses react to stress with their stomachs.
- If your foal has other medical issues, (particularly ones that require additional handling or medication) work with your vet to prevent ulcers. She or he may suggest adding an anti-ulcer medication to your horse’s current regime or feed.
My Foal Has An Ulcer: Now What?
If ulcers are caught before perforating, there’s a good chance your foal will recover after a course of medication. Use the prevention steps above to decrease the chance of recurrence.
