‘Staggers’ is a term used to describe the abnormalities seen in alpacas affected by perennial ryegrass toxicity, annual ryegrass toxicity (ARGT) or phalaris toxicity. Both ryegrasses and phalaris are good pasture grasses and are not in themselves harmful. However, at certain times of the year or under certain seasonal conditions they can become loaded with fungal toxins (ryegrasses) or chemical poisons (phalaris).
Affected animals may develop tremors (fine shaking) of the head and neck and lose control of the co-ordinated movement of their legs; hence the term ‘staggers’. Affected animals should be moved to sheltered areas and provided with shade, food, water and nursing care. Seek veterinary advice to deal with compromised animals. Mildly affected animals recover after two to three days (sometimes up to 14 days) after they are transferred to ‘safe’ pasture.
Pasture species are often specific to geographical regions so staggers may or may not be an issue depending on your location. Learning about your pasture species and their growth cycles is invaluable. If feed regularly becomes very short throughout a property, sow pastures of other species (eg. cocksfoot, phalaris) or forage crops for grazing in the summer-autumn period. Perennial ryegrass with low endophyte or non-toxic endophyte is becoming increasingly available.
Annual ryegrass staggers occurs when stock graze Wimmera ryegrass Lolium rigidum at or after heading and the seed heads are infected with a particular type of nematode and species of bacterium. The bacteria produce a toxin that is fatal to stock. The disease is confined to areas of Western Australia, South Australia and Victoria.
Always seek veterinary advice if you observe an alpaca with difficulty in walking or standing, as other conditions can also cause gait abnormalities.