CASE NOTES
Paspalum staggers (nervous ergotism) in steers
Bruce Watt, Tablelands Livestock Health and Pest Authority, Bathurst and Andrew Denman, Blayney Veterinary Hospital
Posted Flock & Herd September 2011
Introduction
It has been know for over 100 years that sheep, cattle and horses can develop a 'staggers' syndrome after ingesting the seed heads of paspalum (Paspalum dilatatum) infested with the fungus Claviceps paspali. Cattle are most commonly affected, mainly because they predominate in the coastal areas of NSW, Victoria and south western Western Australia where paspalum thrives (AJ Cawdell-Smith et al. 2010, Finnie et al. 2011). The toxin causes degeneration in some brainstem nuclei and the spinal cord (Finnie et al. 2011). However, affected animals usually recover uneventfully if they survive misadventure.
History
Eighty two Angus steers purchased in mid-April 2011, were moved into a paspalum dominant paddock in the Blayney district on the central tablelands of NSW. The paddock had been spelled for 3-4 months and the paspalum was in head. The owner, after a ten-day absence returned in early May 2011 to find two steers unable to stand (Figure 1). He described them as 'scrabbling around on all fours.'
Figure 1. Affected steer in paddock of Claviceps infested paspalum
Clinical Findings
On inspection, the two recumbent steers were alert, reactive and aggressive when approached. When attempting to rise from sternal recumbency, they paddled in an uncoordinated fashion and were unable to gain their feet to stand. They also had muscle tremors.
Several steers in the mob also developed hypermetria and a swaying gait as they were moved under some pressure.
The mob was diagnosed as suffering from paspalum staggers because ergot-affected paspalum (Figure 2) dominated the paddock, the clinical findings in the two recumbent steers was consistent with the disease and also because when the mob was pressed others developed clinical signs.
Figure 2. Paspalum seed heads infected with Claviceps paspali
Treatment and outcome
The mob, apart for the two recumbent steers was moved into a paddock with less paspalum. They recovered uneventfully although forced exercise induced signs of incoordination for 2-3 days after removal. The two recumbent steers were sedated then moved from the affected paddock. One steer recovered after 5 days. The remaining steer was fed and watered for 21 days before regaining its feet.
Discussion
In our experience, paspalum staggers is rare on the tablelands of NSW. This is because paspalum dominant pastures are uncommon. The exceptionally high rainfall over the summer and autumn of 2010-11, conducive to abundant rank growth of paspalum and the development of Claviceps infestation, is also unusual.
The differential diagnosis of 'falling with tremors syndromes' includes phalaris staggers, perennial ryegrass staggers and the mycotoxicosis due to the ingestion of wheat and barley sprouts infected by Aspergillus clavatus (Bourke 2008, Finnie et al. 2011).
References
- Bourke CA. The clinical diagnosis of nervous and muscular locomotor disorders of sheep in Australia. Australian Veterinary Journal 2008; 72:228-234
- Cawdell-Smith AJ, Scrivener CJ and Bryden WL. Staggers in horses grazing paspalum infected with Claviceps paspali. Australian Veterinary Journal 2010; 88:393-395
- Finnie JW, Windsor PA and Kessell AE. Neurological diseases of ruminant livestock in Australia. II: toxic disorders and nutritional deficiencies. Australian Veterinary Journal 2011; 89:247-253