SciELO - Scientific Electronic Library Online

vol.80 número4The intravenous pharmacokinetics of diminazene in healthy dogsA retrospective study of chronic nasal disease in 75 dogs índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados



Links relacionados

  • Em processo de indexaçãoCitado por Google
  • Em processo de indexaçãoSimilares em Google


Journal of the South African Veterinary Association

versão On-line ISSN 2224-9435
versão impressa ISSN 1019-9128

J. S. Afr. Vet. Assoc. vol.80 no.4 Cape Town  2009




Annual ryegrass toxicity in Thoroughbred horses in Ceres in the Western Cape province, South Africa



J D GrewarI; J G AllenII; A J GuthrieI

IEquine Research Centre, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa
IIDepartment of Agriculture and Food, Western Australia, Locked Bag 4, Bentley Delivery Centre, WA, 6983, Australia




An outbreak of annual ryegrass toxicity occurred on a Thoroughbred stud in Ceres in the Western Cape Province of South Africa. This is the 1st report of annual ryegrass toxicity in horses in South Africa, although the condition has been reported in cattle and sheep populations in the past. Annual ryegrass toxicity is characterised by a variety of neurological signs including tremors, convulsions, recumbency and in many cases death. The description of the outbreak includes the history, clinical presentation and treatment protocol administered during the outbreak. Various epidemiological variables and their influence in the outbreak are also considered.

Keywords: annual ryegrass toxicity, horse, corynetoxins, neurological, magnesium sulphate



“Full text available only in PDF format”



1. Allen J G 2004 Annual ryegrass toxicity. In Plumlee K H (eds) Clinical veterinary toxicology. Mosby, St Louis, Missouri: 422-424        [ Links ]

2. Bath G, de Wet J 2000 Annual rye grass toxicity. In Bath G, de Wet J (eds) Sheep and goat diseases. Tafelberg Publishers, Cape Town: 137-140        [ Links ]

3. Berry P H, Howell J M, Cook R D 1980 Morphological changes in the central nervous system of sheep affected with experimental annual ryegrass (Lolium rigidum) toxicity. Journal of Comparative Pathology 90: 603-617        [ Links ]

4. Berry P H, Howell J M, Cook R D, Richards R B, Peet R L 1980 Central nervous system changes in sheep and cattle affected with natural or experimental annual ryegrass toxicity. Australian Veterinary Journal 56: 402-403        [ Links ]

5. Bertozzi T, Davies K A 2009 Anguina paludicola sp. n. (Tylenchida: Anguinidae): the nematode associated with Rathayibacter toxicus infection in Polypogon monspeliensis and Lachnagrostis filiformis in Australia. Zootaxa 2060: 33-46        [ Links ]

6. Botha C J, Venter E 2002 Annual rye grass In Plants poisonous to livestock southern Africa (CD ROM). Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria.         [ Links ]

7. Bourke C A 1994 Tunicaminyluracil toxicity, an emerging problem in livestock fed grass or cereal products. In Colegate S M, Dorling P R (eds) Plant-associated toxins: agricultural, phytochemical and ecological aspects. CAB International, Wallingford, Oxon: 399-404        [ Links ]

8. Creeper J H, Vale W, Walsh R 1996 Annual ryegrass toxicosis in horses. Australian Veterinary Journal 74: 465-466        [ Links ]

9. Davis E O, Curran G E, Hetherington W T, Norris D A, Wise G A, Roth I J, Seawright A A, Bryden W L 1995 Clinical, pathological and epidemiological aspects of flood plain staggers, a corynetoxicosis of livestock grazing Agrostis avenacea. Australian Veterinary Journal 72: 187-190        [ Links ]

10. Dieterich H J, Reutershan J, Felbinger T W, Eltzschig H K 2003 Penetration of intravenous hydroxyethyl starch into the cerebro-spinal fluid in patients with impaired blood-brain barrier function. Anesthesia & Analgesia 96: 1150-1154        [ Links ]

11. Finnie J W 2006 Review of corynetoxins poisoning of livestock, a neurological disorder produced by a nematode-bacterium complex. Australian Veterinary Journal 84: 271-277        [ Links ]

12. Finnie J W, Mukherjee T M 1987 Ultra-structural changes in cerebral blood vessels of sheep injected with tunicamycin. Journal of Comparative Pathology 97: 217-220        [ Links ]

13. Finnie J W, O'Shea J D 1988 Pathological and pathogenetic changes in the central nervous system of guinea pigs given tunicamycin. Acta Neuropathology 75: 411-421        [ Links ]

14. Jago M V, Culvenor C C 1987 Tunicamycin and corynetoxin poisoning in sheep. Australian Veterinary Journal 64: 232-235        [ Links ]

15. Jago M V, Payne A L, Peterson J E, Bagust T J 1983 Inhibition of glycosylation by corynetoxin, the causative agent of annual rye-grass toxicity: a comparison with tunica-mycin. Chemico-Biological Interactions 45: 223-234        [ Links ]

16. Masters A M, Gregory A R, Evans R J, Speijers J E, Sutherland S S 2006 An enzyme-linked immunosorbent assay for the detection of Rathayibacter toxicus, the bacterium involved in annual ryegrass toxicity, in hay. Australian Journal of Agricultural Research 57: 731-742        [ Links ]

17. Morgan K 1998 Thermoneutral zone and critical temperatures of horses. Journal of Thermal Biology 23: 59-61        [ Links ]

18. Neff T A, Doelberg M, Jungheinrich C, Sauerland A, Spahn D R, Stocker R 2003 Repetitive large-dose infusion of the novel hydroxyethyl starch 130/0.4 in patients with severe head injury. Anesthesia & Analgesia 96: 1453-1459        [ Links ]

19. Sadeh M 1989 Action of magnesium sulfate in the treatment of preeclampsia-eclampsia. Stroke 20: 1273-1275        [ Links ]

20. Schneider D J 1981 First report of annual ryegrass toxicity in the Republic of South Africa. Onderstepoort Journal of Veterinary Research 48: 251-255        [ Links ]

21. Stuart S J, Leury B J, Edgar J A 1992 Plasma clearance of tritiated-tunicamycin in sheep. Proceedings of the Nutrition Society of Australia 17: 137-137        [ Links ]

22. Stynes B A, Bird A F 1983 Development of annual ryegrass toxicity. Australian Journal of Agricultural Research 34: 653-660        [ Links ]

23. Than K A, Cao Y, Michalewicz A, Edgar J A 1998 Development of an immunoassay for corynetoxins. In Garland T, Barr A C (eds) Toxic plants and other natural toxicants. CAB International, Wallingford, Oxon: 49-54        [ Links ]

24. Vogel P Petterson D S, Berry P H, Frahn J L, Anderton N, Cockrum P A, Edgar J A, Jago M V, Lanigan G W, Payne A L, Culvenor C C 1981 Isolation of a group of glycolipid toxins from seedheads of annual ryegrass (Lolium rigidum Gaud.) infected by Corynebacterium rathayi. Australian Journal of Experimental Biology and Medical Science 59: 455-467        [ Links ]



Received: July 2009
Accepted: October: 2009



* Author for correspondence. E-mail:

Creative Commons License Todo o conteúdo deste periódico, exceto onde está identificado, está licenciado sob uma Licença Creative Commons