A Case of Closantel Toxicity in Crossbred Lambs

In mid-March 2015 approximately 400 September 2014 drop Dorset cross Merino lambs from a property near Hill End on the central tablelands of NSW were shorn and drenched with 10 ml of a commercial closantel and abamectin mix (Genesis Xtra, Ancare containing 1g/L abamectin and 50g/L closantel, recommended dose 1 ml/5kg bodyweight, equivalent to 10mg closantel/kg). Two weeks later, several lambs were noticed blind, 2-3 of which died.