Cattle Medicine Q&A 09

This question was provided by Manson Publishing as part of the OVAL Project. See more Cattle questions

A group of beef cattle presents with 4 weeks’ history of pruritus and extensive hair loss especially over the shoulder, neck, and ears. The cattle are frequently observed rubbing against walls and fence posts.

Question	Answer		Article
What conditions would you consider?	The most likely conditions to consider include: lice (pediculosis); forage mites; sarcoptic mange; chorioptic mange; ringworm (Trichophyton spp. infection).		Link to Article
Which further tests could be undertaken?	Inspection of the skin reveals extensive louse infestation. Microscopic examination of skin scrapings reveal numerous chewing (round mouthparts; Damalinia bovis) and sucking lice (narrow and more pointed mouthparts; Linognathus vituli).		Link to Article
What actions/treatments would you recommend?	Treatment options include pour-on organophosphorous or pyrethroid (e.g.cypermethrin) compounds that effect rapid improvement but may require retreatment in 2–4 weeks. All in-contact cattle must be treated. Injectable avermectin products are not always wholly effective against chewing lice. Pediculosis is widespread in all beef herds and routine treatment is recommended at housing. Interestingly, bulls are invariably more severely affected than cows.		Link to Article
Are there any consequences of this problem?	Disruption to grazing/feeding may cause reduced liveweight gain/loss of body condition in severe infestations, although very heavy burdens are more often a consequence rather than the cause of debility. Anaemia, as a consequence of severe infestations, is rare.		Link to Article