Thoracic ultrasonography as an adjunct to clinical examination in sheep

Modern portable ultrasonography machines provide veterinary clinicians with an inexpensive and non-invasive method to further examine the respiratory system of sheep on farm. The procedure would take no more than 2-5 min, with results immediately available. Repeated, regular ultrasonographic examination allows lung and pleural pathologies to be monitored over time, permitting accurate evaluation of various treatments regimens. Critically, ultrasonographic examination informs the clinician regarding the development/regression of lesions, rather than relying upon extrapolation of post-mortem findings regarding aetiology and progression of disease. Ultrasonographic examination presents no human health and safety restrictions. Lesion as small as 2-3 cm in diametre, involving the visceral pleura can be readily identified ultrasonographically. The distribution of lung pathology caused by ovine pulmonary adenocarcinoma can be accurately outlined during ultrasonographic examination of the chest, but the operator must be aware that secondary abscessation of the tumour mass and associated fibrinous pleurisy may prove misleading. Repeated 6- to 12-monthly ultrasonographic examination of the lungs of all adult sheep in a flock is an exciting development that may reduce, and potentially eliminate, pulmonary adenocarcinoma from closed sheep flocks, with effective biosecurity measures. With appropriate handling facilities, an experienced operator can examine both sides of the chest of 50-80 sheep per hour, making such screening affordable even to commercial farmers. Resolution of extensive unilateral fibrinous pleurisy over several months has been recorded and in some cases it has proven difficult to differentiate such resolving lesions from abscesses involving the lungs/pleurae.