Lice and mites

When cattle are indoors, they generally are at extremely low exposure to gut parasites, unless they are being fed zero grazed grass. However, external skin parasites such as lice and mites can cause a number of issues.

Low sunlight, thick coats and close contact help these external skin parasites thrive indoors.

Consequences

Scratching and irritation can make cattle uncomfortable, reduce growth/performance and also reduce the possibility for other diseases.

Symptoms

Both lice and mites can cause scratching, irritation (tail swishing), licking and hair loss. The amount of irritation can depend on the number of lice or mites present. Mites penetrate deeper into the skin and tend to cause more severe symptoms, while lice cause irritation on the skin.

Identification

There are two forms of lice – sucking and biting. This is important because some injectable treatments like ivermectin will only kill sucking lice. All topical preparations of ivermectin and synthetic pyrethroids should kill lice. Lice are visible to the naked eye, while mites cannot be seen.

There are a number of mite species, whiach creates issues as not all treatments are effective against certain types.

I have seen a number of these cases in the last two years where we had to change the product used and also dose more frequently.

Where pour on treatments are being used, backs should be clipped.

Solutions

If you have had yearly problems with lice and mites, early intervention works best. Dairy farmers are limited to using eprimectin pour on or injections, but really pyrethroids should probably be the first stop for prevention in dairy stock (they are cheaper and should be effective).

Just remember an early treatment may reduce the build up of parasites but may mean a second treatment is needed, depending on the length of housing

Resistance

Where the same product is used year after year, there can be some some resistance. If your first treatment hasn’t worked, get more advice on skin scrapes or other treatment options.