Characterisation of localised pigment accumulation in brains of eastern grey kangaroos (Macropus giganteus) after clinical disease due to chronic Phalaris species toxicosis

Abstract

A progressive tremorgenic syndrome characterised by ataxia and head nodding is well documented in sheep and cattle affected by chronic Phalaris toxicosis (CPT), and is increasingly documented in the eastern grey kangaroo {(EGK), Macropus giganteus} in southeastern Australia. It is characterised on gross necropsy by areas of acquired localised pigment deposits within the brain. This pigment was previously considered a storage disease, but more recently has been determined to be a metabolic breakdown product of tryptamine alkaloids within Phalaris species (spp) of introduced grasses. The study included 61 EGKs that were euthanased after a diagnosis of clinically advanced CPT, histopathological..