Abomasal Ulcers in Cows: Bleeding, Pain, and When to Call the Vet

Quick Answer
  • Abomasal ulcers are sores in the cow's true stomach and can range from mild irritation to life-threatening bleeding or perforation.
  • Common warning signs include reduced appetite, lower milk production, teeth grinding, belly pain, dark tarry manure, pale gums, weakness, or sudden collapse.
  • See your vet immediately if your cow has black manure, signs of shock, severe abdominal pain, or rapid decline. Perforated ulcers can cause peritonitis and become fatal quickly.
  • Diagnosis often relies on history, physical exam, fecal occult blood testing, bloodwork, ultrasound, and sometimes abdominal fluid sampling because ulcers are hard to confirm early.
  • Typical 2025-2026 US cost range: farm exam and basic workup $250-$600; fuller diagnostics and medical treatment $600-$1,800; intensive care, transfusion, referral, or surgery can exceed $2,000-$5,000+ depending on severity and travel.
Estimated cost: $250–$5,000

What Is Abomasal Ulcers in Cows?

Abomasal ulcers are erosions or deeper sores in the lining of the abomasum, the cow's true stomach. Some ulcers stay superficial and may cause only vague signs like poor appetite or lower production. Others bleed into the stomach, and some perforate the stomach wall, leading to localized or widespread peritonitis. Merck notes that classification is based on depth, bleeding, and whether perforation and peritonitis are present. (merckvetmanual.com)

These ulcers matter because the clinical picture can change fast. A cow with a mild ulcer may look off-feed for a few days, while a cow with a bleeding or perforated ulcer may become weak, painful, anemic, or collapse. Black, tarry manure called melena is a classic clue for bleeding into the upper digestive tract. (merckvetmanual.com)

Abomasal ulcers are seen in both adult cattle and calves, but the risk factors can differ by age and management stage. In adult dairy cows, the period around calving and early lactation is a well-recognized high-risk time because feed intake, metabolism, and stress are all shifting at once. (rgs-ntgs.ch)

Symptoms of Abomasal Ulcers in Cows

  • Mild to moderate drop in appetite or selective eating
  • Lower milk production or poor weight gain
  • Teeth grinding, tucked-up posture, or reluctance to move
  • Abdominal guarding or signs of belly pain
  • Dark, tarry manure (melena), which suggests bleeding from the abomasum
  • Pale mucous membranes, weakness, or faster heart rate from blood loss
  • Fever, dehydration, rumen atony, and worsening depression if peritonitis develops
  • Sudden collapse, shock, or death in severe hemorrhage or diffuse perforation

Some cows with abomasal ulcers show only vague signs at first, which is why the condition is often missed early. Merck reports that mild bleeding can be difficult to diagnose, while perforating ulcers may look like other causes of peritonitis. In cows with severe perforation and generalized peritonitis, studies describe anorexia, abdominal guarding, rumen atony, tachycardia, tachypnea, and a markedly compromised overall condition. (merckvetmanual.com)

See your vet immediately if you notice black manure, pale gums, weakness, collapse, severe belly pain, fever, or a rapid drop in appetite and production. Those signs can point to major blood loss or perforation, and waiting can sharply worsen the outlook. (merckvetmanual.com)

What Causes Abomasal Ulcers in Cows?

Abomasal ulcers do not have one single cause. They are usually linked to a mix of stress, reduced feed intake, diet change, concurrent disease, and damage to the stomach's protective lining. Merck states that stress appears to be a major contributing factor, even though the exact mechanism likely varies between animals. Examples include transport, regrouping, heat stress, and dehorning in calves. (merckvetmanual.com)

In adult dairy cows, risk is highest around late pregnancy and early lactation. This is a period of major metabolic strain, lower dry matter intake, ration changes, and increased risk of other fresh-cow diseases. Research on perforated ulcers in cows highlights later pregnancy and early lactation as important periods where ulcerogenic factors should be minimized. (rgs-ntgs.ch)

In calves, management factors may include feeding practices, environmental stress, concurrent illness, and in some systems, abomasal damage associated with intensive production. Veal calves are reported to have especially high rates of abomasal damage at slaughter, although many lesions are not the same as catastrophic perforating ulcers. (pubmed.ncbi.nlm.nih.gov)

Medication history also matters. Merck advises avoiding NSAIDs when abomasal ulcers are suspected because these drugs can contribute to ulcer formation in monogastric species and may worsen concern in cattle. Your vet will weigh pain control against ulcer risk based on the whole case. (merckvetmanual.com)

How Is Abomasal Ulcers in Cows Diagnosed?

Diagnosis usually starts with a careful farm history and physical exam. Your vet will look at appetite, manure color, hydration, heart rate, rumen activity, abdominal pain, temperature, and whether the cow is showing signs of anemia or shock. If melena is present, abomasal ulcer rises on the list, but your vet still has to rule out other causes of blood in the manure and other painful abdominal diseases. (merckvetmanual.com)

Merck notes that repeated fecal occult blood testing may help in mild bleeding cases. Bloodwork can help assess the degree of hemorrhage or inflammation, including packed cell volume and other indicators of blood loss or peritonitis. (merckvetmanual.com)

If perforation is suspected, transabdominal ultrasonography and abdominocentesis are especially useful. Ultrasound can support a diagnosis of peritonitis, and abdominal fluid analysis may show inflammatory or septic changes. In severe type-4 ulcers with generalized peritonitis, published work supports using hematocrit, plasma protein concentration, ultrasound, and peritoneal fluid analysis together because clinical signs alone are not reliable enough. (merckvetmanual.com)

Sometimes the diagnosis remains presumptive rather than perfectly confirmed before treatment decisions are made. That is common in field medicine. Your vet may recommend treatment, close monitoring, referral, or humane euthanasia depending on whether the ulcer appears mild, bleeding, localized, or diffusely perforated. (merckvetmanual.com)

Treatment Options for Abomasal Ulcers in Cows

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$250–$800
Best for: Stable cows with mild signs, no collapse, and no strong evidence of severe hemorrhage or diffuse peritonitis
  • Farm call and physical exam
  • Assessment of hydration, pain, manure color, and rumen function
  • Basic supportive plan to improve feed intake and buffering with palatable forage or ration adjustment as directed by your vet
  • Targeted medical treatment your vet considers appropriate for a presumptive mild, non-perforating case
  • Close recheck instructions and monitoring for melena, weakness, fever, or worsening pain
Expected outcome: Fair to good when the ulcer is mild or non-perforating and the cow keeps eating. Recovery often takes about 1-2 weeks if the case responds.
Consider: Lower upfront cost, but less diagnostic certainty. A bleeding or perforating ulcer can be missed early, so monitoring must be very close.
Most Common

Recommended Standard Treatment

$600–$1,800
Best for: Most cows with suspected ulcers that are sick enough to need more than watchful care but are still candidates for treatment on-farm
  • Farm exam plus fuller diagnostics such as fecal occult blood testing, CBC/PCV-total solids, and chemistry as available
  • Transabdominal ultrasound when perforation or peritonitis is a concern
  • IV or oral fluids, ration support, and medical therapy tailored by your vet
  • Broad-spectrum antimicrobials for suspected perforating ulcers, as Merck recommends for at least 5 days or until temperature is normal for 48 hours
  • Discussion of milk and meat withdrawal times for any drugs used
Expected outcome: Good for many localized or non-perforating cases; guarded if there is significant blood loss or suspected perforation.
Consider: More complete information and support, but higher cost range and more labor. Some adult-cow acid-suppressing medications can be difficult to use effectively and may add cost.

Advanced / Critical Care

$2,000–$5,000
Best for: Cows with collapse, severe melena, marked anemia, suspected generalized peritonitis, or complex abdominal disease
  • Referral or intensive herd-side care for shock, severe anemia, or diffuse peritonitis
  • Aggressive IV fluids and repeated laboratory monitoring
  • Blood transfusion in severe hemorrhagic cases
  • Ultrasound-guided abdominal fluid evaluation and repeated reassessment
  • Surgery in selected cases, mainly when ulcer disease is found with displaced abomasum or another surgical abdominal problem
  • Humane euthanasia discussion when diffuse peritonitis or irreversible shock makes recovery unlikely
Expected outcome: Highly variable. Localized perforation may still recover, but diffuse peritonitis carries a poor prognosis and may not be effectively treatable.
Consider: Most intensive option and may improve stabilization or clarify prognosis, but cost range rises quickly and some severe ulcer types remain poor candidates for successful treatment.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Abomasal Ulcers in Cows

Bring these questions to your vet appointment to get the most out of your visit.

  1. Do my cow's signs fit a mild ulcer, a bleeding ulcer, or a perforated ulcer with peritonitis?
  2. What tests are most useful on-farm right now: fecal occult blood, bloodwork, ultrasound, or abdominal fluid sampling?
  3. Is my cow stable enough for treatment on the farm, or do you recommend referral, surgery, or euthanasia discussion?
  4. What feeding changes could help buffer the abomasum and support healing in this specific cow?
  5. Are there concurrent fresh-cow problems, calf illnesses, or medication risks that may have contributed to this ulcer?
  6. What warning signs mean I should call you back immediately today or tonight?
  7. What is the expected cost range for conservative, standard, and advanced care in this case?
  8. What milk or meat withdrawal times apply to the medications you are using?

How to Prevent Abomasal Ulcers in Cows

Prevention focuses on lowering the factors that irritate the abomasum or reduce its normal protection. The biggest practical steps are consistent feed access, avoiding abrupt ration changes, supporting strong dry matter intake, and reducing stress where possible. Merck emphasizes that getting cattle to eat is important because feed helps buffer the abomasum. (merckvetmanual.com)

For dairy cows, the transition period deserves special attention. Good fresh-cow management includes minimizing overcrowding, limiting empty feed bunks, reducing unnecessary pen moves, and watching closely for ketosis, displaced abomasum, metritis, mastitis, and other illnesses that can suppress appetite. These are management steps your vet and nutrition team can tailor to your herd. (merckvetmanual.com)

In calves, prevention may include reviewing milk or milk replacer mixing, feeding frequency, environmental stress, pain control plans, and colostrum and disease management. If your herd has repeated ulcer cases, ask your vet to review housing, feeding procedures, medication use, and timing of stressful events. (pmc.ncbi.nlm.nih.gov)

Use NSAIDs thoughtfully and only under veterinary direction, especially in animals with poor appetite, abdominal pain, or suspected ulcer disease. Prevention is rarely one product or one change. It is usually a herd-level plan that matches nutrition, stress reduction, and early disease detection to the cattle in front of you. (merckvetmanual.com)

Find a Vet Near You