During May and June 2016 SAC Consulting Veterinary Services investigated three separate incidents of lamb mortality following inhalation of copper containing mineral drenches. Affected flocks reported multiple deaths of six to eight week old lambs following handling for multiple management tasks. These included administration of anthelmintic and mineral drenches, Clostridial and Orf vaccination, tagging, castration and application of topical ecto-parasiticides. Some lambs exhibited coughing and respiratory distress post treatment with one farm reporting deaths within 15 minutes. Other lambs were found dead during the subsequent 24 hour period. The possibility of an adverse vaccine reaction prompted investigation in some cases.
Post mortem examination was carried out on five lambs from three flocks. Patchy lung congestion +/- consolidation was detected but bacteriology was unrewarding. Pericardial effusion and the detection of epsilon toxin suggested the possibility of pulpy kidney in two lambs but histopathology did not support this diagnosis. In all cases histopathology of lung revealed airway necrosis consistent with recent inhalation of an irritant substance. Copper analysis carried out on multiple samples of lung tissue produced results above the normal range.
These incidents highlight the need for care when administering oral minerals to young lambs particularly when multiple management tasks are being carried out. Necropsy findings could be mistaken for either Pasteurellosis or pulpy kidney. A history of recent handling should prompt further investigation and allow the correct diagnosis to be reached.