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Blindness in goats following ingestion of Stypandra glauca
Author(s) -
WHITTINGTON RJ,
SEARSON JE,
WHITTAKER SJ,
GLASTONBURY JRW
Publication year - 1988
Publication title -
australian veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.382
H-Index - 59
eISSN - 1751-0813
pISSN - 0005-0423
DOI - 10.1111/j.1751-0813.1988.tb14295.x
Subject(s) - optic nerve , blindness , medicine , pathological , optic neuropathy , biology , ophthalmology , anatomy , pathology , optometry
SUMMARY: Twenty‐seven of 427 Angora goats of mixed age became blind within a week of consuming large amounts of Stypandm glauca (“nodding blue lily”). A further 200 goats were depressed for several weeks, but most subsequently recovered. Blindness was associated with optic nerve neuropathy which is postulated to have followed compression of the optic nerves within the bony optic canals as a result of severe myelin oedema. Histologically, the intracanalicular portion of the optic nerve was sclerotic, while the intracranial portion of the optic nerve and the optic tracts were degenerating. The retrobulbar portion of the optic nerve was relatively unaffected. In addition, multifocal retinal photoreceptor degeneration was found ophthalmoscopically and histologically. The syndrome was not reproduced during a trial in which 2 goats were fed 4 and 20 kg of S. glauca harvested after it had finished flowering, more than 3 weeks after the first natural cases of blindness. Based on epidemiological and pathological data we propose that S. glauca is toxic to stock, but only for a short period while flowering in spring.