Stock Sense with Paul McKee Ravensdown Technical Manager

The sight of little tufts of wool appearing along fencelines could also be a hit to your bottom line. These tufts are a tell-tale sign your ewes are itching and scratching because of lice. Although lice can be present year-round, it is during cooler months infestations rapidly increase on individual animals and throughout a flock.

Infestations left uncontrolled will have ewes spending more and more of their time rubbing and biting at themselves in the drive to find relief. The end result is increased matting and damage to wool fibres and a costly reduction in the value of the wool harvested at shearing.

A combination of mechanical and chemical treatments is best employed to ensure lice populations are controlled. Regularly shearing ewes is the primary control option, where up to 80-90 per cent of the lice can be removed from your sheep.

A post-shearing application of dip chemicals can remove most, if not all, of the remaining lice. Although there is resistance to some chemicals, incorrect application will be more often than not be the reason for failure of a treatment to control an infestation.

Incomplete saturation, under-dosing, too long a wool length and mis-mustering are all things that can lead to ‘treatment failures’. Correctly applying an effective chemical at the required rate will give you the best chance to achieve lice control.

Generally, the sooner after shears the chemical can be applied, the better. Controlling lice infestations on ewes in winter will also reduce the lice problems on lambs born in spring. At a time when every part of the animal value needs to be maximised, farmers need to ensure they keep lice infestations in check.

Talk to your animal health representative for help on developing an effective lice control programme this winter.