Lice warning as wet weather forces cattle to be housed

A disease alert has been issued to farmers housing cattle indoors amid a record-breaking wet winter.

The latest National Animal Disease Information Service (Nadis) disease outlook has warned of an increasing risk of lice infestation, suggesting pyrethroid treatments or back-clipping for preventative purposes.

Somerset veterinarian James Aitken of Orchard Veterinary Group advises that lice infestations are “relatively simple” to treat, being easily killed by pyrethroid products including pour-ons, sprays or dusting powders.

See also: Read more about how to treat lice in cattle by taking our online academy

He reassures that Ivermectin-based pour-on wormers will kill all lice and injectable Ivermectin will kill all sucking lice and 98% of biting lice.

He says an average louse has a lifespan of about a month, during which time they will lay a few hundred eggs.

“These products will usually be effective for all the lice to hatch,” says Mr Aitken.

“A second treatment may occasionally be required.

“For preventative purposes, these treatments can be given to at-risk cattle at housing, accompanied by clipping the hair down the ridge of the back to the tail base, where many lice prefer to live.”

Mr Aitken adds that signs of infestation are “fairly obvious”, with skin irritation causing cattle to rub against gates and feed barriers.

“Even with the mild December, fields in Somerset have been too wet to get cattle out and many cattle have been housed for some time now, increasing the risk of lice infestation,” says Mr Aitken.

“There are five species of lice affecting cattle categorised as four sucking lice, which feed on blood, and one chewing louse, which feeds on surface debris.”

When examining bald patches, farmers may see adult, nymph-stage and egg-stage lice, which Mr Aitken says may be more visible with a magnifying glass.