Cow with "Hardware Disease"

History. A 4-year-old, pregnant Holstein cow is presented for lethargy, poor appetite, and edema. She is due to calve in 2 months. The producer noticed that over the last few weeks the cow has seemed progressively more lethargic and reluctant to move.

Clinical Examination. The cow appears depressed. She is dehydrated. Her mucous membranes are dark (indicating poor perfusion), and capillary refill time is prolonged. She has marked brisket and submandibular edema. Her jugular veins are prominent. She grunts when she moves. Her temperature, pulse, and respiratory rates are all increased. Her heart sounds are muffled (as if heard through fluid), and she has a murmur (“washing machine” murmur). She has increased broncho­vesicular (respiratory) sounds dorsally, but the sounds are muf­fled ventrally. Peripheral pulses are weak. Rumen contractions are decreased (one every 1-3 minutes). Feces are scant. Blood is submitted for a complete blood count and chemistry pro­file. Results indicate that the white blood cell count is low and serum creatinine concentration is increased. Fibrinogen, globulins, and total protein are all increased. Calcium and potassium levels are low.

An electrocardiogram reveals decreased amplitude of QRS complexes and ST segment elevation. Fxhocardiography reveals excessive fluid and gas in the pericardial space. Fibrin tags are also present. The right atrium and right ventricle appear to “collapse” during diastole, which is consistent with Ciirditk' tιwιpι)Hιide (excessive pericardial fluid pushing in on the heart). The left ventricle also contracts less forcefully and less completely than normal during systole (“decreased left ventricular free wall motion”).

With guidance from the echocardiogram, a sample of peri­cardial fluid is obtained.

Comment. This cow has traumatic Teticuloperitonitis with pericarditis. Traumatic reticιdoρeritoιιitis (TRP), or “hardware disease,” is common in cattle. Cattle are indiscriminate eaters, and they accidentally swallow sharp metal objects that get mixed into their feed. Metal objects settle in the reticulum of the rumen. Contractions of the reticulum may push sharp objects through the wall of the reticulum and into the peri­toneum. Bacteria follow and cause peritonitis. Subsequently, the sharp object may penetrate the diaphragm, which is located just cranial to the reticulum, and may then move on to pene­trate the pericardium. The consequence is pericarditis (inflam­mation of the pericardium). Sequelae include formation of scar tissue (seen as fibrin tags), pericardial bacterial infection, and accumulation of inflammatory fluid in the pericardium. The pericardial fluid presses on the cardiac chambers, restrict­ing their filling during diastole, and this causes pump failure.

Evidence of congestive pump failure in this cow includes poor perfusion (weak pulses, dark mucous membranes, and prolonged capillary refill time), cardiac abnormalities (sub­normal right atrial and ventricular filling, decreased left ven­tricular motion), elevated heart rate, distended jugular veins, edema, and lethargy.

Treatment. Prognosis is poor in this case because of the combination of pericardial infection and congestive pump failure. The producer could try to treat the infection, in hopes of delivering a live calf. Because the cow is already in pump failure with very limited cardiac output, however, it is likely that the calf is not receiving sufficient blood flow and oxygen. The calf could die in utero and could be aborted by the cow.