Abstract
Auscultation is considered the critical component of the veterinary clinical examination for the diagnosis of bovine respiratory disease but the accuracy with which adventitious sounds reflect underlying lung pathology remains largely unproven. Modern portable ultrasound machines provide the veterinary practitioner with an inexpensive, non-invasive tool with which to examine the pleural surfaces and superficial lung parenchyma. Simultaneous recording of sounds overlying normal lung and defined pathology allows critical assessment of auscultated sounds in the same animal removing confounding factors such as respiratory rate and thickness of the chest wall (body condition). Twelve cows, referred to the University of Edinburgh Veterinary School, were diagnosed with chronic suppurative pneumonia and enrolled into this prospective study to record and monitor lung sounds, ultrasonographic findings, and response to a standardised antibiotic treatment regimen.Most cows (8/12) had a normal rectal temperature on presentation but all cows had received antibiotic therapy at some time in the previous two weeks and six animals were receiving antibiotic treatment upon admission. All cattle were tachypnoeic (>40 breaths per minute) with frequent and productive coughing, halitosis, and a purulent nasal discharge most noticeable when the head was lowered. Ultrasonographic examination of the chest readily identified pathological changes consistent with severe lung pathology subsequently confirmed as chronic suppurative pneumonia in four cows at necropsy; eight cows recovered well after antibiotic treatment and were discharged two to six weeks after admission. It proved difficult to differentiate increased audibility of normal lung sounds due to tachypnoea from wheezes; coarse crackles were not commonly heard. In general, sounds were reduced in volume over consolidated lung relative to normal lung tissue situated dorsally. Rumen contraction sounds were commonly transmitted over areas of lung pathology.Trueperella (formerly Arcanobacterium) pyogenes was isolated from three of four lung tissue samples at necrospy. Treatment with procaine penicillin for 42 consecutive days resulted in marked improvement with return to normal appetite and improvement in body condition in 8 of 12 cows (67%) where lesions did not extend more than 10-15 cm above the level of the olecranon on both sides of the chest.