Occasionally eggs may be seen adhered to hairs on the edges of balding areas. A magnifying glass sometimes reveals the adult or nymph stages. Animals may be restless and itchy. Animals that scratch ends up with patches of hair loss.

Treatment
In problem situations where sheep are heavily infested with lice, apply backline treatments on the day of shearing or dip within three to four weeks. Most products on the market for sheep have several weeks of efficacy. For complete removal of all lice, the product must not only treat adults, but nymphs emerging from eggs.

Calves and kids can be treated with powders or pour-on.

In some cases a follow-up treatment may be required after 10 to 14 days to catch the new lice hatching after the first treatment. The worming products containing Ivermectin type actives are extremely effective at treating lice, especially when used as a pour-on preparation.