Look out for white tail in young sheep

Sheep farmers are being urged to watch for a common debilitating disease in young stock, with several cases already diagnosed this year in the Riverina.

Eperythrozoonosis, sometimes known as ‘white tail’, causes fever, depression, anaemia, pale mucus membranes and a failure to thrive in lambs and weaners. The worst affected sheep also develop a stagger, rapid respiration, stiffening in the hindquarters, and possibly death if forced to move when mustering.

According to Riverina Livestock Health and Pest Authority district vet Colin Peake, merinos are more susceptible to the disease and losses of up to 30% of young sheep can occur, especially if they are stressed in situations such as mustering or yarding.

"The disease is also more severe if sheep suffer conditions such as gastrointestinal worms or malnutrition," he said.

Eperythrozoonosis is caused by bacteria called Mycoplama ovi, which is found in the bloodstream of sheep and destroys the red blood cells of non-immune sheep.

"Infection and spread usually happens after winter when blood sucking insects such as mosquitoes become active. It can also be spread rapidly through management procedures which cause bleeding such as marking, mulesing, ear tagging and shearing, with many outbreaks occurring four to six weeks after these events," said Dr Peake.

"Early diagnosis is best, but first you need to rule out other causes of anaemia and ill thrift, such as barber’s pole worm, liver fluke, leptospirosis and chronic copper poisoning, which require a different form of treatment. You should then take a number of blood samples from the affected mob of sheep for lab testing which will provide the best chance of finding the organism which causes white tail.

"As Eperythrozoonosis is a self limiting disease, the best treatment is usually to avoid handling and to leave the affected mob alone in a paddock with good feed and water for four to six weeks, where they should recover. If this isn’t effective or there are large losses of sheep, antibiotics could be considered."

To minimise spread of the disease Dr Peake suggests not yarding lambs or weaners in the four to six weeks after any procedures which cause bleeding, and ensuring good hygiene when implementing these procedures.

"It’s also important to ensure lambs and weaners are healthy and on good feed before and after marking, mulesing or shearing, and to develop a program which eliminates the need to yard young sheep within six weeks of these procedures," he said.

For further information on Eperythrozoonosis contact your local Riverina LHPA district vet or your private vet.

Media contact: Vanessa Delaney 02 6391 3787 or 0428 465 378