WormBoss worm control program

Qld/NSW Summer rainfall/slopes and plains

Grazing management

Effective grazing management reduces the exposure of sheep to worms. There are three methods:

• Avoid paddocks heavily contaminated with worm larvae.
• Reduce contamination of paddocks with worm eggs.
• Allow time for most of the eggs and larvae on the pasture to die.

The last two are used to prepare ‘low worm-risk’ paddocks for lambing ewes and weaners.

How are low worm-risk lambing and weaning paddocks prepared?

Ewes temporarily lose some of their immunity to worms at and after lambing. As a result, they contribute greatly to the seasonal increase in worm numbers and subsequent infection of lambs.
Weaners are also highly susceptible to worms. Low worm-risk weaning paddocks give weaners a good start so they can build immunity without suffering high initial infections.

To prepare a low worm-risk paddock

Whether the paddock is for lambing ewes or for weaned lambs the method of preparation is the same. However, the length of preparation will vary according to the time of the year the paddock first needs to be used. Refer to Table 1 (below) to find out how long you need to prepare your paddock.

Preparation: In the months (see Table 1 below) before it is required for use as a lambing or weaning paddock, prevent contamination of the paddock with sheep worm eggs by any combination of these:

• spelling (including cropping and haymaking)
• grazing with sheep for up to 21 days after the protection period of a drench shown to be effective (in a DrenchTest) on your property. The protection period of a drench is when it is killing worms: 1–2 days for short-acting drenches, weeks or months for persistent products.
• grazing with cattle

Table 1. Months of preparation required for low worm-risk paddocks

* includes towns such as Narrabri, Moree, Warwick and Dalby
** includes towns such as Nyngan, Walgett, St George and Mitchell

Other ways to prepare low worm-risk paddocks

Rotational grazing with short graze periods alternated with rest periods can greatly reduce the number of worm larvae on pasture, especially barber’s pole worm. While these systems (e.g. planned grazing, cell grazing, techno-grazing and intensive rotational grazing) are outside the scope of this publication, and may not be applicable to producers in this region, they use the principles found in Factors contributing to paddock contamination with worms.