Keep sheep parasites at bay

Page last updated: Wednesday, 21 March 2018 - 11:15am

Please note: This content may be out of date and is currently under review.


There are two major types of worms that affect sheep in Western Australia; barber’s pole and scour worms.

The adult worm lays eggs in the digestive system of the sheep. The eggs pass out of the sheep and hatch as larvae in the pasture, where they are ingested by the sheep through grazing, become adult worms, and the cycle begins again.

Worms can cause damage to the lining of the gut, poor appetite, diarrhoea (scour worms), or weakness and death due to blood depletion (barber’s pole worm).

By the time a sheep is visibly affected, the infestation is severe.

The main signs of barber’s pole worm are weakness and anaemia (pale membranes of the mouth and eyes).

Scour worms will result in weight loss, weakness and diarrhoea (scouring).

Carrying out a regular worm egg count (WEC) by submitting faecal samples to a veterinarian is the best way to keep a handle on worm burdens.

Drenching should only be carried out when necessary, as worms can become resistant to the drench if it is used indiscriminately, making control more difficult.

Good nutrition can help sheep to overcome the effects of worms, and also to develop a natural resistance to worms.

Livestock owners should consider rotationally grazing their animals as part of their worm prevention strategy. Rotational grazing is the practice of moving stock from one paddock to another once the feed becomes relatively low or after a set time in a paddock.

By moving sheep from one paddock to the next any worm eggs which have been expelled by the sheep and hatched will be less likely to be picked up.

When you see visible signs of worm infestation, such as diarrhoea, investigate the cause immediately.

Once an accurate diagnosis is made, treatment of affected animals to prevent the problem getting worse is strongly recommended.

You should also seek advice in relation to a whole of flock preventative worming program.

Affected animals, which do not respond to treatment, and are not likely to recover, should be examined by a vet or humanely destroyed.

The effect worms can have on your flock will vary depending on how bad the infestation is, the resilience of your animals, and the type of worm.

Discuss with your vet for advice specific to your flock, or visit the WormBoss website.