Abomasal Ulcers in Sheep

Quick Answer
  • Abomasal ulcers are sores in the lining of the true stomach. In sheep, they may be mild and hard to spot or severe enough to cause internal bleeding or peritonitis.
  • Common warning signs include reduced appetite, teeth grinding, belly pain, weakness, pale gums, black tarry manure, poor thrift, and sudden collapse in severe cases.
  • See your vet immediately if a sheep has black manure, marked weakness, pale eyelids, a tucked-up painful abdomen, fever, or sudden death in the group.
  • Diagnosis is often presumptive and based on history, exam findings, anemia, fecal blood or melena, ultrasound, and ruling out parasites, enterotoxemia, and other causes of abdominal pain.
  • Treatment depends on severity and may include diet and stress correction, fluids, blood transfusion in major blood loss, antimicrobials if perforation is suspected, and close monitoring.
Estimated cost: $150–$3,500

What Is Abomasal Ulcers in Sheep?

Abomasal ulcers are erosions or deeper sores in the lining of the abomasum, the sheep’s true stomach. When the damage extends into deeper tissue, the ulcer can bleed, cause pain, or even perforate the stomach wall. Mild ulcers may cause vague signs like poor appetite or slower growth. Severe ulcers can lead to black tarry manure, anemia, shock, or peritonitis.

In sheep, this condition is less commonly discussed than in cattle, but the same disease process can occur. Stress, inconsistent feed intake, concurrent illness, and heavy abomasal parasite burdens can all contribute to stomach lining injury. Some sheep show only subtle changes until the disease is advanced.

For pet parents and flock managers, the challenge is that abomasal ulcers can look like several other sheep problems. A sheep may seem off feed, painful, weak, or suddenly down. That is why early veterinary evaluation matters, especially when there is evidence of blood loss or abdominal pain.

Symptoms of Abomasal Ulcers in Sheep

  • Reduced appetite or going off feed
  • Teeth grinding or signs of abdominal pain
  • Tucked-up belly, reluctance to move, or lying apart from the flock
  • Poor growth, weight loss, or declining body condition
  • Weakness, lethargy, or exercise intolerance
  • Pale eyelids or gums from blood loss anemia
  • Black, tarry manure (melena), which suggests digested blood
  • Fast heart rate, dehydration, or collapse in severe cases
  • Fever and marked abdominal pain if perforation and peritonitis develop
  • Sudden death in acute hemorrhage or diffuse peritonitis

Some sheep with abomasal ulcers have only vague signs at first, such as eating less, acting dull, or grinding their teeth. Others become weak because of slow internal blood loss. Black tarry manure, pale mucous membranes, collapse, or severe belly pain are more urgent signs and should prompt same-day veterinary care.

See your vet immediately if a sheep is down, very weak, has a painful rigid abdomen, or seems to be deteriorating quickly. Those signs can mean heavy bleeding or a perforated ulcer with peritonitis, which can become life-threatening fast.

What Causes Abomasal Ulcers in Sheep?

Abomasal ulcers usually develop when the stomach lining loses its normal protection and acid or local tissue injury damages deeper layers. In ruminants, risk factors include stress, reduced feed intake, sudden management changes, transport, heat stress, crowding, and concurrent disease. When sheep do not eat well, there is less buffering from ingesta moving into the abomasum, and the lining may be more vulnerable.

Diet and management can also play a role. Irregular feeding, abrupt ration changes, high-concentrate feeding programs, and poor overall nutritional balance may increase risk in some flocks. Ulcers may also occur secondary to other illness rather than as a stand-alone problem.

Parasites matter too. The abomasum is the site affected by important small-ruminant parasites such as Haemonchus contortus and other trichostrongyles. These parasites can damage the abomasal lining and cause anemia, which may overlap with or worsen ulcer disease. That is one reason your vet may recommend fecal testing, FAMACHA scoring, and a broader flock-health review instead of focusing on the stomach alone.

How Is Abomasal Ulcers in Sheep Diagnosed?

Diagnosis is often presumptive, meaning your vet pieces it together from the sheep’s history, physical exam, and supportive test results. Important clues include reduced appetite, abdominal pain, black manure, weakness, pale mucous membranes, and signs of anemia or shock. In ruminants, melena can be a strong clue that bleeding from the upper digestive tract is occurring.

Your vet may recommend a complete blood count to look for anemia, protein changes, inflammation, or dehydration. Fecal testing may help assess parasite burden and rule in or out other causes of anemia or poor thrift. Ultrasound can sometimes support the diagnosis, especially if there is concern for fluid, localized peritonitis, or another abdominal problem.

Because sheep can have similar signs with heavy barber pole worm infection, enterotoxemia, intestinal bleeding, toxicities, or other abdominal emergencies, diagnosis also involves ruling out look-alike conditions. In some cases, the diagnosis is only confirmed on necropsy after death, which is why prompt evaluation of sick flockmates is so important.

Treatment Options for Abomasal Ulcers in Sheep

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

Budget-Conscious Care

$150–$450
Best for: Mild, stable cases where the sheep is still standing, still drinking, and does not show severe anemia, collapse, or signs of peritonitis.
  • Farm call or outpatient exam
  • Focused physical exam with FAMACHA and hydration assessment
  • Basic supportive care plan
  • Feed and management review to improve intake and reduce stress
  • Targeted parasite evaluation or fecal testing if indicated
  • Oral medications selected by your vet when appropriate
  • Close home or flock monitoring for manure color, appetite, and weakness
Expected outcome: Often fair to good if the ulcer is mild, bleeding is limited, and the underlying trigger is corrected early.
Consider: This approach keeps costs lower, but it may miss complications like significant blood loss, perforation, or another disease causing similar signs.
Most Common

Recommended Standard Treatment

$450–$1,200
Best for: Sheep with ongoing pain, black manure, moderate weakness, suspected blood loss, or uncertain diagnosis that needs more than watchful care.
  • Veterinary exam and repeat reassessment
  • CBC and basic lab work to check anemia, inflammation, and hydration
  • Fecal testing and parasite-control plan if needed
  • Ultrasound or additional diagnostics when available
  • Prescription acid-reducing or mucosal-protectant medications chosen by your vet
  • Fluids, pain-control plan when appropriate, and dietary support
  • Antimicrobials if perforation or secondary infection is suspected
Expected outcome: Good for many nonperforating ulcers treated early; guarded if anemia is worsening or if the sheep has major concurrent disease.
Consider: This tier gives better diagnostic clarity and monitoring, but it costs more and may still be limited if the sheep needs hospitalization or transfusion.

Advanced / Critical Care

$1,200–$3,500
Best for: Sheep with collapse, severe anemia, shock, suspected perforated ulcer, diffuse peritonitis, or rapid deterioration.
  • Emergency evaluation and hospitalization
  • IV fluids and intensive monitoring
  • Serial bloodwork to track anemia and shock
  • Blood transfusion for severe hemorrhage when indicated
  • Broad-spectrum antimicrobials for suspected perforation or peritonitis
  • Advanced imaging and intensive supportive care
  • Referral-level management for valuable breeding animals or complex cases
Expected outcome: Guarded to poor for perforated ulcers with diffuse peritonitis; better when bleeding or localized complications are recognized and treated before shock develops.
Consider: This tier offers the most monitoring and support, but the cost range is much higher and outcomes can still be poor in severe perforating disease.

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

Questions to Ask Your Vet About Abomasal Ulcers in Sheep

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

  1. Do my sheep’s signs fit abomasal ulcer disease, or are parasites or another abdominal problem more likely?
  2. Is there evidence of blood loss anemia, and how severe is it right now?
  3. Should we run a CBC, fecal testing, or ultrasound to guide treatment?
  4. What treatment options fit this sheep’s condition and my flock goals?
  5. Does this sheep need hospitalization, fluids, or a blood transfusion?
  6. Which medications are appropriate in sheep, and which drugs should we avoid?
  7. Could feed changes, stress, lambing, transport, or another illness have triggered this?
  8. What signs mean I should call back immediately or separate this sheep from the flock for closer monitoring?

How to Prevent Abomasal Ulcers in Sheep

Prevention focuses on steady management and early intervention. Keep feed intake consistent, avoid abrupt ration changes, and make transitions to grain or new forage gradually. Good-quality forage, reliable water access, and minimizing overcrowding help support normal rumen and abomasal function.

Stress reduction also matters. Transport, regrouping, heat stress, lambing pressure, and concurrent illness can all increase risk. Try to plan management changes thoughtfully and monitor vulnerable sheep closely during high-stress periods. Sheep that go off feed should be checked promptly rather than waiting several days.

A strong parasite-control plan is another key step. Because abomasal parasites can damage the stomach and cause anemia, work with your vet on fecal testing, targeted deworming, pasture management, and FAMACHA-based monitoring where appropriate. Good flock records help too. If several sheep show poor thrift, black manure, or unexplained weakness, early veterinary review can prevent bigger losses.

Find a Vet Near You