title: Nigropallidal encephalomalacia in horses grazing Rhaponticum repens (creeping knapweed).
abstract: Nigropallidal encephalomalacia was diagnosed in two horses in northern Victoria that had a history of long-term pasture access to a dense growth of Rhaponticum repens. The region in which the affected horses lived had received well above average rainfall for several months preceding the poisoning. Affected horses had sudden onset of subcutaneous oedema of the head, impaired prehension and mastication, dullness, lethargy and repeated chewing-like jaw movements. Diagnosis was confirmed at necropsy, with characteristic malacic lesions in the substantia nigra and globus pallidus of the brain. This is the first documented case of nigropallidal encephalomalacia in Australian horses associated with R. repens.
authors.affiliation: Blackdown Equine Clinic, Midhurst Rd, Fernhurst, Haslemere, Surrey, GU27 3EX, UK. chrisbvsc@gmail.com
authors.forename: C R B
authors.initials: CR
authors.lastname: Elliott
authors.forename: C I
authors.initials: CI
authors.lastname: McCowan
mesh_terms: D000818:Animals; D004678:Encephalomalacia / Q000175:diagnosis / Q000662:veterinary*; D017809:Fatal Outcome; D005917:Globus Pallidus / Q000473:pathology; D006734:Horse Diseases / Q000175:diagnosis*; D006736:Horses; D043843:Leuzea; D008279:Magnetic Resonance Imaging / Q000662:veterinary; D008297:Male; D010939:Plant Poisoning / Q000150:complications / Q000662:veterinary*; D013378:Substantia Nigra / Q000473:pathology; D014739:Victoria