Abomasal Ulcers in Cattle

Abomasal ulcers most commonly occur within the first six weeks of lactation. Metabolic disorders such as ketosis and displacement of the abomasumalso  occur  at  this   same  time.   Stress, lymphosarcoma, and diets high in concentrates have been suggested as predisposing factors.

Four types of abomasal ulcers are: 1) Non-perforating ulcers involving the mucosa and submucosa have vague clinical signs including decreased gut motility, partial anorexia, mild abdominal pain, and stale feces. Traumatic reticuloperitonitis or indigestion must also be considered with this presentation. Fecal occult blood tests may be positive. 2) Severe blood loss can occur with a nonperforating ulcer when the ulcer erodes into a major gastric blood vessel.

Hemorrhage,   anemia,   black   tarry   feces, tachycardia,tachypnea or shock may result. Abomasal ulcers are the most common cause of proximalgastrointestinal hemorrhage in cattle. Another major cause of melena is intussusception. Intussusception may result in an increased PCV, whereas blood loss by ulceration will cause a decreased PCV. 3) Perforating ulcers with local peritonitis are caused by penetration through to the serosal layers with localized leakage of abomasalcontents. The inflammatory response is quick to wall off localized peritonitis and signs may be similar to traumatic reticuloperitonitis. The prognosis is good with antibiotic therapy, except in pregnant cows where the gravid uterus interferes with adhesion formation. 4) Perforating ulcers with diffuse peritonitis are a result of serosal penetration and widespread contamination of the peritoneum. Signals of rapid septic shock within 24 hours, including   anorexia,   tachycardia,   bruxism, abdominal distention and terminal recumbency follow.

Abomasal ulcers may present subclinically, when the ulcer is small and has not penetrated the gastric mucosa, or with hemorrhage and peritonitis.

The most useful test for diagnosis of gastrointestinal bleeding is the fecal occult blood test.   Peritonitis   can   be   confirmed   by abdominocentesis. (Localized walled off peritonitis may give normal results.) Severe blood loss will result in decreased PCV. Anemic cattle over five years-of-age should be tested for bovine leukemia (BLV).

At necropsy the lesion in the abomasum is usually small and involves an abomasal blood vessel. A single bleeding ulcer in the ventral portion of the abomasum is most commonly seen.

The treatment of abomasal ulcers is limited primarily to correcting dietary problems, reducing stress and treating concurrent disease. Antacids, protectants and H:>- blockers such as cimefidine are ineffective. All affected cattle should be tested for BLV, as lymphosarcoma can be a cause of abomasal ulcers.

Epidemiology indicates that all ages are affected. Many calves sent to slaughter have inapparent erosions and ulcers. In one study of adult cattle with abomasal ulcers one third had significant hemorrhage, one third had localized peritonitis and one third had diffuse peritonitis.

- Patrick Petrowski, Ross University

- edited by Lydia Andrews-Jones, DVM