Get smart in summer drenching

After a year of grazing on shorter-than-usual pastures, many sheep across Victoria are facing higher-than-normal worm burdens.

But with summer's hot and dry conditions around the corner, producers have a timely opportunity to tackle the issue head-on.

It's time to consider strategic summer drenching, a targeted approach involving effective treatments at the start and end of the season. The goal is to take advantage of the natural destruction of worm larvae on pastures caused by the heat and desiccation of summer.

However, not all sheep may require treatment. Pre-drench faecal egg counts (FECs) will help determine which parts of the flock actually need drenching. This deliberate step helps avoid unnecessary costs and ensures treatments are justified.
Drenching is only effective when done correctly. Using the wrong chemicals or misusing them can reduce their effectiveness and contribute to the development of resistance.

Post-drench FECs are also advisable, to assess how well the treatment worked and to detect any signs of drench resistance, a growing concern in Victoria, particularly with white and clear drenches.

To maximise results, producers should move treated sheep to low-risk pastures. Ideal options include paddocks that have been previously grazed by cattle, cut for hay or silage, or used by older wethers.

Ewes around the time of lambing and recently weaned lambs are especially vulnerable to worm infestations. Without an effective drenching program, reinfestation can occur in as little as three weeks.