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Victorian worm update - February 2012

Tricia Veale, Benalla (

Areas of recent rain, including in the northeast of Victoria, coupled with very warm conditions in most locations, has encouraged worm populations to increase steadily. This area received 66mm in February.

Worm egg counts on some properties recently show that the worms are well and truly multiplying. Egg counts in lambs and weaners are often climbing up to over 1,000 eggs per gram of dung.

Despite hot conditions and brown grass, the worms are surviving and being sheltered close to the ground. It's very important to test animals to determine the worm burden.

Now is the time for the second summer drench.

It's very important NOT to give a second summer drench unless it is really necessary.

Drenching when not needed will help the worms to get used to that chemical, which is how drench resistance begins. This is because you kill all the susceptible worms in the population…allowing the drench resistant ones to survive.

So if you are in doubt I strongly suggest that you get a worm egg count done. You may wish to test a group of younger sheep, some middle-aged and some older ones to obtain a comprehensive picture of the worm status of your property.

Also, make sure that you have a plan of your drenching regime which makes the efficient drenches last as long as possible on your property.

It is a serious mistake to use one type of drench only every year for a few years. This actively encourages the appearance of resistant worms.

If you own a sheep property where Barber’s Pole worms, Haemonchus, are present, then I suggest that you keep an eye out for these blood suckers. Get a larval culture done to identify the species of worms present.

Flystrike is a major problem in this area and most farmers are watching their animals closely.

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