Hardware disease

Diagnosis

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.

Treatment

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 is often considered for both economic and humane reasons.

Prevention

Good feed management is also important; in smaller operations, some farmers pass metal detectors or magnets over the feed.

Cow magnet

A cow magnet is a veterinary medical device for the treatment or prevention of hardware disease in cattle. Traditionally, cow magnets were strong Alnico magnets about 1 by 8 cm (0.39 by 3.15 in) in the shape of a smoothed rod, but today they are more commonly several ring-shaped ferrite magnets attached to a stainless-steel or plastic core, in the same shape as the single-piece original. Newer designs to help increase effectiveness include a cage design, in which the magnet holds metal objects inside a protective plastic framework. Even newer designs include a stronger array of rare-earth magnets inside a stainless steel body that resembles the original Alnico design.

A rancher or dairy farmer feeds a magnet to each calf at branding, leading the magnet to settle in the rumen or reticulum to remain there for the life of the animal. Some magnets have a loop that fits under the cow's tongue so that they can be retrieved.

The magnet is administered after fasting the cow for 18–24 hours. This is most effective if done to the entire herd before the age of one.

The cow magnet attracts such objects and prevents them from becoming lodged in the animal's tissue. While the resultant mass of iron remains in the cow's rumen as a pseudobezoar (an intentionally introduced bezoar), it does not cause the severe problems of hardware disease.

Cow magnets are widely available from veterinary, feed supply, and scientific supply sources.