<P> Cattle commonly swallow foreign objects, because they do not use their lips to discriminate between materials and they do not completely chew their feed before swallowing . Sharp metallic objects, such as nails or wire, are the common initiators of hardware disease . The object travels into the rumen and is then pushed into the reticulum along with the rest of the feed . In some cases, contractions of the reticulum can push the object through part of the reticulum wall into the peritoneal cavity, where it causes severe inflammation . In rare cases, the metal object penetrates the entire wall of the reticulum and can pierce the heart sac, causing pericarditis . Compression by the uterus in late pregnancy, straining during parturition and mounting during estrus can increase the likelihood of the object penetrating the abdominal wall or the heart sac . </P> <P> Diagnosis is typically based on history and clinical findings when the veterinarian examines the cow . Symptoms of hardware disease vary depending on where the object penetrates . The cow exhibits an arched back, a reluctance to move and a slow, careful gait . The cow may groan when lying down, getting up, defecating and urinating . The heart rate is normal or slightly elevated, and the respiration is shallow and rapid . In dairy cows, there is often a decrease in milk production . Laboratory tests are not always necessary, but increases in fibrinogen and total plasma protein often result from hardware disease and may be diagnosed with a blood sample . Electronic metal detectors can be used, but not all heavy sharp objects will be metal and it does not distinguish between penetrating and nonpenetrating bodies . Radiographs are also used and are advantageous because the location of the metallic body can be identified . However, if the sharp object is not metallic or dense enough the radiograph is of no use . If there is inflammation in either the Peritoneal cavity or the Pericardium, it can be detected using an ultrasonograph . </P> <P> If hardware disease is suspected, a magnet should be administered orally through a tube into the reticulum . Depending on the type of magnet used, inserting a second magnet could cause internal pinching which could lead to serious complications . A broad - spectrum antibiotic should also be given to control infection . The cow should be confined and movement limited in the hopes that the reticulum can repair the hole . Surgery is necessary in some cases and involves rumenotomy with a physical removal of the object . In some advanced cases that don't respond to medical or surgical therapy, slaughter should be considered from an economic perspective . </P> <P> Good feed management is also important; in smaller operations, some farmers pass metal detectors or magnets over the feed . </P>

Why do you put a magnet in a cow's stomach