Cyanide poisoning in cattle from Dysphania glomulifera (red crumbweed): using the internet for rapid plant identification and diagnostic advice.
A 300-strong Angus-Brahman cattle herd near Springsure, central Queensland, was being fed Acacia shirleyi (lancewood) browse during drought and crossed a 5-hectare, previously burnt area with an almost pure growth of Dysphania glomulifera subspecies glomulifera (red crumbweed) on their way to drinking water. Forty cows died of cyanide poisoning over 2 days before further access to the plant was prevented. A digital image of a plant specimen made on a flat-bed scanner and transmitted by email was used to identify D glomulifera. Specific advice on the plant's poisonous properties and management of the case was then provided by email within 2 hours of an initial telephone call by the field veterinarian to the laboratory some 600 km away. The conventional method using physical transport of a pressed dried plant specimen to confirm the identification took 5 days. D glomulifera was identified in the rumen of one of two cows necropsied. The cyanogenic potential of D glomulifera measured 4 days after collection from the site of cattle deaths was 18,600 mg HCN/kg in dry matter. The lethal dose of D glomulifera for a 420 kg cow was estimated as 150 to 190 g wet weight. The plant also contained 4.8% KNO3 equivalent in dry matter, but nitrate-nitrite poisoning was not involved in the deaths.
Department of Primary Industries & Fisheries, Biosecurity Sciences Laboratory, Animal Research Institute, Lacked Mail Bag 4, Moorooka, QLD 4105, Australia. ross.mckenzie@dpi.qld.gov.au
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McKenzie
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Burren
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Noble
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Thomas
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis / Q000401:mortality*; D003486:Cyanides / Q000506:poisoning*; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D020407:Internet; D009566:Nitrates / Q000506:poisoning; D009573:Nitrites / Q000506:poisoning; D010939:Plant Poisoning / Q000175:diagnosis / Q000401:mortality / Q000662:veterinary*; D011793:Queensland / Q000453:epidemiology; D013997:Time Factors
D003486:Cyanides; D009566:Nitrates; D009573:Nitrites