REVIEW Review of neurological diseases of ruminant livestock in Australia. VI: postnatal bovine, and ovine and caprine, neurogenetic disorders PA Windsor, a * AE Kessell b and JW Finnie c This paper, the last in a series of reviews of neurological diseases of ruminants in Australia, discusses a range of neurogenetic disorders of cattle, sheep and goats, including necrotising encephalomyel- opathy, glycogen storage disorders, cerebellar abiotrophy and b-mannosidosis. They are categorised by the species and breeds in which they occur. Keywords Australia; cattle; goats; neurogenetic diseases; rumi- nants; sheep Abbreviations IPS, inherited periodic spasticity; NCL, neurovis- ceral ceroid-lipofuscinosis; OMIA, Online Mendelian Inheritance in Animals; PCR, polymerase chain reaction; TSE, transmissible spongi- form encephalopathies Aust Vet J 2011;89:432–438 doi: 10.1111/j.1751-0813.2011.00834.x T his is the final paper in a series of reviews designed to provide an overview of the major neurological diseases affecting ruminant livestock in Australia in order to facilitate the diagnosis of endemic and emerging disorders, plus enhance sur- veillance for incursions of exotic diseases. Previously, the principles of neurological examination, necropsy procedures, trauma and neo- plasia were examined, 1 as well as toxic disorders and nutritional deficiencies, 2 infectious neurological disorders 3,4 and congenital neu- rogenetic disorders. 5 This paper focuses on those neurogenetic dis- orders that occur outside the immediate postpartum period in cattle, as well as neurogenetic diseases recognised in sheep and goats in Australia. An ability to readily diagnose the neurogenetic disorders presenting in adult livestock is of particular importance in the surveillance for trans- missible spongiform encephalopathies (TSEs), as they may present with symptoms or spongiform lesions that have initially been consid- ered suggestive of such a diagnosis, as in segmental axonopathy of Merino sheep. 6,7 The detection and reporting of neurodegenerative diseases of ruminants is assisted by examining the literature, cross- referenced with OMIA (Online Mendelian Inheritance in Animals: http://omia.angis.org.au/). If available, the OMIA identity for each disorder has been included. Postnatal hereditary and familial disorders and the abiotrophies of cattle Angus Cerebellar abiotrophy (OMIA 000175). This is a form of degen- eration that is considered premature with respect to normal aging, suggesting that after some period of normal cerebellar function, degeneration results in chronic locomotor dysfunction. It has been described in Angus cattle and their crossbreds in Australia. Clinical signs included a fine head tremor, generalised muscle tremor, forelimb hypermetria, hindlimb ataxia and increased responsiveness to touch and noise. When standing, affected calves have a wide-based stance, hold their heads high and tend to lose their balance. When chased, the calves have a bounding, ataxic gallop, often leading to collapse and seizures characterised by opisthotonus and paddling lasting 2–3 min. Clinical signs persist and affected animals showed no signs of recov- ery. Gross lesions are not observed, with histological lesions found in the cerebellar cortex characterised by deficiency of cells in the Purkinje layer, swollen axons in the granular layer and accumulations of glial cells around blood vessels in the molecular layer of the cer- ebellum. 8 Investigations should aim to exclude the common bovine pestivirus-induced cerebellar hypoplasia associated with intrauterine infection at approximately 150 days gestation or the possibility of exposure to tremorgenic toxins from plant or fungal origin. The later onset of cerebellar signs suggests that the Australian cases of cerbellar abiotrophy in Angus cattle differ from‘familial convulsions and ataxia’ of Angus cattle described from Scotland and New Zealand. Multifocal symmetrical necrotising encephalomyelopathy (OMIA 001488). This condition has been described as three differ- ent syndromes in Australia, occurring in Limousin, Simmental and Angus calves. The disorder is characterised by symmetrical lesions of cystic malacia of parts of the brain and spinal cord, but the three syndromes have distinctive differences in the age of onset and distri- bution of lesions. In Australian Angus calves, onset is at 2–6 weeks of age, with death occurring 4–7 days after onset of clinical signs characterised by ataxia, muscular tremors, opisthotonos, bruxism, hyperaesthesia and episodic convulsions leading to tetanic spasms. Symmetrical lesions of cystic cavitation involving the dorsal nucleus of the vagus nerve, lateral cuneate and olivary nuclei of the medulla *Corresponding author. a Faculty of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia; peter.windsor@sydney.edu.au b Gribbles Veterinary Pathology, Adelaide, South Australia, Australia c Hanson Institute Centre for Neurological Diseases, Institute of Medical and Veterinary Science, Adelaide, SA, Australia PRODUCTION ANIMALS PRODUCTION ANIMALS © 2011 The Authors Australian Veterinary Journal © 2011 Australian Veterinary Association Australian Veterinary Journal Volume 89, No 11, November 2011 432