Overcoming ectoparasite problems

SCAB AND lice are an increasing problem for UK sheep flocks, but a new management programme provides a clear approach to ectoparasite control, reducing wasted treatments.

“Sheep producers are confused about the efficacy of different ectoparasite treatments,” says sheep consultant Lesley Stubbings who devised the programme. “There is a lack of clear information about when they should be used for maximum impact in different situations.

“In many flocks this confusion means money is wasted on the wrong treatments, given at inappropriate times,” said Ms Stubbings, who launched the programme to Lake District producers at a National Trust organised meeting.

The programme follows three basic steps. The first is to identify risk factors and assess the flock’s level of security. The second to decide what preventative measures to use to minimise risk of ectoparasite attack. The third is to integrate these measures into an overall ectoparasite strategy to maximise their effect and minimise cost.

Ms Stubbings’ management programme and guidance notes give a much-needed blueprint for ectoparasite treatment. This can be easily incorporated into an existing flock management timetable to achieve a higher degree of control of scab, mites and lice.

It allows assessment of individual level of risk using a simple scoring system. Circumstances which influence risk level include purchased replacements, purchased stores, sheep away on tack, common fence lines with a neighbour”s sheep and use of common grazing.

“When a producer has calculated the total score for a flock, the figure places it in one of three risk groups – easily secured, potentially secure and insecure.” Ms Stubbings has created an action plan for each group with a simple timetable of treatment. It is split into three sections – class of stock, the planned treatment – dipping and/or quarantine and month of treatment.

“The aim is to achieve maximum protection, integrate treatments into existing management practices, reduce handling and hassle, while achieving the most effective use of products. This can cut the need for re-treatment and, therefore, lower costs.”

Producers running flocks in a high risk group must also be aware of exactly what parasites are covered by a treatment and length of protection afforded. This can vary according to the products, which include organophosphorous dips, synthetic pyrethroid dips, Moxidectin and pour-ons, she warned.

“Most diseases enter a flock with purchased sheep or those returning from market or tack. All in-coming stock should be quarantined until treated and remain in isolation, for at least 16 days after scab treatment. Never rely on a guarantee given by the vendor,” said Ms Stubbings.

Other flocks in the high risk group include those using common grazing. She recommends treating sheep on return from common grazing. “And it’s worth considering turning sheep out on common grazing with some degree of protection.”

To effectively integrate ectoparasite treatments into existing flock management, Ms Stubbings has designed a 12-month chart. “On this producers should record important dates, such as lambing, weaning and tupping, plus identify times sheep come onto the farm and when they’re moved on to or from high risk areas. The farm’s main risk periods for ectoparasites are also recorded on the chart followed by the proposed treatments.”

Ms Stubbings said producers should then ask themselves whether their strategy leaves the flock exposed during a risk period and whether they could they have done something more effective.