Vena caval thrombosis and metastatic pneumonia is associated with multifocal abscesses in the lung as the result of embolism of the pulmonary arterial vascular system arising from septic thrombi in the caudal vena cava. The most common cause of vena caval thrombosis is ruminal acidosis leading to rumenitis and subsequent liver abscessation, which may result in a thrombus in the caudal vena cava if the vessel wall is infiltrated by the abscess. Treatment is usually unrewarding and control of the disease is largely achieved by careful management of feeding programs when adapting cattle to high grain diets.
Etiology of Vena Caval Thrombosis and Metastatic Pneumonia in Cattle
Bacteria most frequently involved in vena caval thrombosis and metastatic pneumonia include Fusobacterium necrophorum, Trueperella pyogenes, staphylococci, streptococci, and Escherichia coli.
Clinical Findings of Vena Caval Thrombosis and Metastatic Pneumonia in Cattle
Vena caval thrombosis and metastatic pneumonia usually occurs in adult dairy cattle or in feedlot cattle on high-carbohydrate diets. Presenting clinical signs can be acute, manifested by respiratory distress, or be chronic, manifested by weight loss and chronic coughing. A common presentation is tachypnea, tachycardia, hemic murmurs, coughing, pale mucous membranes, increased lung sounds, hemoptysis, and epistaxis. Pyrexia and melena may also be present. The condition is almost always fatal.
Lesions on Post-Mortem Examination
A thrombus is found in the vena cava, and hepatic abscesses may be noted. A suppurative pneumonia is present with multifocal pulmonary abscesses, aneurysms, and blood clots from ruptured aneurysms found throughout the entire lung parenchyma. The generalized distribution of these lesions, due to hematogenous spread, is characteristic of this condition.
Treatment and Control of Vena Caval Thrombosis and Metastatic Pneumonia in Cattle
Antimicrobial therapy will usually not be effective and treatment is largely unrewarding
Nutritional management
Adaption periods
Because of the poor prognosis, treatment of vena caval thrombosis and metastatic pneumonia is not indicated. If attempted, treatment includes antimicrobials and supportive care; however, antimicrobial treatment will usually not be effective and is largely unrewarding. Control efforts should focus on nutritional management to decrease the incidence of ruminal acidosis, which can result in rumenitis and subsequent formation of liver abscesses. Adaption periods are necessary when introducing high-grain diets.
Key Points
Multifocal abscessation of lungs resulting from septic emboli disseminated from liver abscessation.
The primary inciting cause is ruminal acidosis.
Vena caval thrombosis and metastatic pneumonia is an important cause of respiratory disease in adult dairy cattle and feedlot cattle on high carbohydrate diets.
Gradual adaption and careful management of high carbohydrate diets is a key prevention strategy.
