Diagnosis of respiratory disease in adult cattle using ultrasonography

In veterinary textbooks wheezes are described as prolonged musical sounds that usually occur during inspiration, and occasionally throughout the breath cycle, resulting from vibration of airway walls caused by air turbulence in narrowed airways. Crackles are loud, explosive, short duration (typically 10–30 mseconds), non-musical, ‘rattling or bubbling’ sounds. Crackles are thought to be caused by air bubbling through, and causing vibrations of respiratory secretions within the larger intrathoracic airways, including those that are pooling within the dependent part of the rostral thoracic trachea.

A recent article in The Veterinary Record commented on the generally poor diagnostic performance of lung auscultation as a confirmatory test for pneumonia in cattle (Pardon et al, 2019), which could concern farmers and potentially lead to inappropriate use of antimicrobials. The authors further suggested that improvements in diagnostic accuracy could be made by using lung ultrasound examination as a reference test. These findings were not surprising because previous articles had shown the inability of chest auscultation to identify and quantify lung and pleural pathologies in sheep (Scott et al, 2010) and adult cattle (Scott, 2013). An accurate assessment of respiratory pathology is essential to establish the likely cause, select an appropriate antibiotic and offer an informed prognosis. The potential application of ultrasound examination in adult cattle is clearly demonstrated in Figures 1 and 2, and video recording [Video 1], taken before and after administration of the correct antibiotic.