Lice have been on the increase the last few years and it appears resistance to the ivermectin products may be part of the problem.
As well, treatment timing, proper application, weather conditions and dosage could be factors.
The type of lice can make a difference because biting lice feed on the skin surface, move around and require a residual product to get the job done most effectively.
That is why ivermectin was so effective and it also got rid of internal parasites.
A new product called Clean-Up II provides another viable option for lice control in Western Canada. It contains two compounds: permethrin, a commonly used compound in many products like Boss or its equivalent, plus an insect growth regulator (IGR) diflubenzeron, which inhibits egg development.
These two active ingredients allow Clear-Up II to target lice in all life stages, including eggs, which can almost eliminate a lice population with one treatment.
The dosage is three cubic centimetres per 100 pounds, up to a maximum of 30 cc.
I like the application method, which is along the back. It is important to spread the product out from head to tail and keep cattle dry after administering for at least two hours, otherwise product can wash off.
Clear-Up II eliminates the need for retreatment and greatly reduces the lice population.
It can be used on lactating cows with no milk withdrawal and a one-day slaughter withdrawal.
It was brought in under an emergency-use registration through the Pesticides Management Regulatory Agency at the request of veterinarians in Alberta, Saskatchewan, Manitoba and Ontario. It is available to producers through their veterinarians.
You must use it according to the label. The current use of the drug is restricted to treating lice in cattle. In the United States, it is labelled for other species as well.
Clean-Up II is absolutely not for use in oilers. It is not a good idea to use it for flies because we want to keep it effective for lice control.
We need to work together to maintain effectiveness by rotating products when necessary to avoid development of resistance in pests.
This product may be one to use where retreatment is not possible or for fall applications when giving ivermectin a rest.
A product such as Clean-Up II used together with Safe-guard, for example, could provide deworming and lice control.
Roy Lewis works as a veterinarian in Alberta.