Cattle are indiscriminate eaters and may inadvertently ingest wire, nails or needles if present in feed. If these sharp metal objects are longer than 2.5 cm, they may become trapped in and penetrate the reticulum. The leakage of gut content into the abdominal cavity then causes the disease, traumatic reticuloperitonitis. Compression of the abdomen during advanced pregnancy, coughing, and mounting behaviour are thought to increase the likelihood of penetration.
Complications of TRP include reticular abscesses, splenic and liver abscesses, reticular fistula formation and vagus indigestion. If the penetrating metal migrates into the diaphragm it may cause diaphragmatic hernia, thoracic disease (pleurisy, pneumonia) and pericarditis (traumatic reticulopericarditis - see Heart failure). Some animals may die suddenly from heart failure associated with traumatic reticulopericarditis.
Inappetence, fever and an arched stance with abducted elbows should raise suspicions of acute localised peritonitis. There may be a painful grunt when the animal is forced to move. Muffled heart sounds, jugular pulse and brisket oedema indicate pericarditis has developed. Many animals simply become illthrifty.
Differentiating abomasal ulceration, pleuropneumonia and indigestion from TRP is tricky but may be possible using manual pressure to localise pain response. With abomasal ulcer there is mid ventral abdominal pain, with pleurisy there is thoracic pain, with indigestion there is no pain and with TRP there is anterioventral abdominal pain.
At necropsy there may fibrin, pus and adhesions involving the abdominal surface of the reticulum. The diaphragm and the contents of abdominal, thoracic or pericardial cavities may be involved. A wire, nail or needle may be found in the lumen or wall of the reticulum.
Oral administration of a magnet may immobilise the penetrating metal if it migrates or falls back into the lumen of the reticulum. A 3-7 day course of systemic antibiotic therapy (procaine penicillin, ceftiofur, or oxytetracycline) should be administered. If signs persist, a laparotomy and rumenotomy may be required to remove the metallic penetrant. Non-steroidal anti-inflammatory drugs (flunixin meglumine, ketoprofen, meloxicam, or tolfenamic acid) may be required for pain relief and to get animals standing and eating.
TRP may be prevented by oral administration of magnets which eventually lodge in the reticulum and may then prevent metal from penetrating the reticulum. Manufacturers of processed feed may use large magnets on production lines to remove metallic contaminants.