Lice reported as increasing problem by vets and farmers

Farmers and vets are reporting that lice are becoming more problematic in cattle over the winter housing period. These findings come from a recent Intervet-sponsored discussion group on parasites, at which the escalating problem of lice infestations was voiced by both vets and farmers.

“It is difficult to pinpoint any one reason for the apparent increase in lice, but the withdrawal of many powder treatments over the past few years and the increased use of pre-housing, injectable combined parasite treatments (for example ivermectin) that have little effect against biting lice could be partly responsible,” explains Intervet’s large animal veterinary adviser, Rosemary Booth.

If left untreated, biting and sucking lice can have serious repercussions. Heavy infestations can lead to debilitated animals with irritated skin and considerable discomfort. A bad sucking lice infestation can lead to potentially fatal anaemia in some cases. Although it is normally youngstock that are at most risk, older cows can be affected too.

The advice from Ms Booth is to use a long-acting pour-on fly control product containing deltamethrin, which can be very effective for the control of both biting and sucking lice infestations. “Choosing the correct product can result in significant cost savings,” adds Ms Booth.

“Recommended application rates for lice can be different to those for flies and farmers should check with manufacturers’ guidelines to ensure the most costeffective product is used. If in doubt, farmers should discuss the available options with their prescribing professional,” concludes Ms Booth.