To scan or not to scan? The economics of transthoracic ultrasonography for 'whole-flock' ovine pulmonary adenocarcinoma screening in UK sheep flocks.

The results of this study emphasise that great caution should be exercised by practitioners when determining if TTUS is appropriate as a screening test for OPA in low-prevalence flocks or subpopulations within a flock, such as younger age groups, where the losses incurred through the inadvertent culling of healthy sheep may significantly exceed any benefit derived from culling preclinical/subclinical cases.