November to Jan is the normal time we would expect to see problems associated with ARGT and I have already started to get some enquires regarding the disease. 

ARGT is caused by a toxin producing bacteria Rathayibector toxicus. The bacteria are carried from the soil onto growing ryegrass grass plants by a nematode (worm).  The toxins are produced as the ryegrass matures and hays off, and are extremely toxic.  ARGT has the potential to kill up to 90% of stock grazing infected ryegrass pastures.

ARGT causes neurological disorders and its effects become most visible when the animals are stressed or excited (i.e. moving a mob). All grazing animals (sheep, cattle, goats, horses), of any age and either sex, are susceptible.

Animals usually show the first symptoms 2 to 6 days after entering a toxic paddock, but it can take longer.  Only a small amount needs to be eaten to see signs of toxicity and it can also build up to toxic levels if animals ingest small amounts repeatedly.  Signs of ARGT include a high-stepping gait, loss of coordination in the hind limbs, falling over with convulsions and lying on the ground neck arched and legs rigidly extended.  Stock can die immediately or up to eight days after the onset of symptoms and deaths can continue to occur after stock has been removed from the toxic paddock.

There is no known treatment for stock affected by ARGT. Regular checking of stock is important to detect symptoms early. When an animal shows ARGT symptoms immediately move stock quietly to a safe paddock.  Avoid stressing the animals as this increases the effects of the toxins. If possible, move the stock to a paddock with shade and water.

Infected ryegrass often appears healthy but a field assessment can detect deformed heads, bacterial galls and maybe slime.  Laboratory tests are required to quantify the levels of toxin present.  Testing costs approximately $55 and pre-flowering or mature ryegrass seed heads can be tested.  Sample bags are available from the PIRSA Kadina office.

If you have deaths that could possible be caused by ARGT I would be interested in hearing about it, as I am trying to collect data on the distribution of ARGT across the YP.  As far as I am aware the problem is fairly widespread. Over the last two years deaths have been reported at Moonta, Weetulta & Warooka.

AUTHOR: Leanne Pridham, Animal Health Officer, Kadina

CONTACT: Leanne Pridham, Telephone 8821 1555, Mobile 0427 274 102