Scratching The Surface: What Is Making My Cattle Itchy?

Background: Producers and veterinarians have reported situations where cattle have lost hair and showed signs of being “itchy” even after being treated with a pour-on product (e.g., Ivomec, Dectomax, Cydectin, etc.). The assumption made is that lice are developing resistance to these products. However, some veterinarians who have investigated these cases report that they haven’t found lice in all of these cases. Besides biting and sucking lice, other potential causes of itching include other parasites (e.g., microscopic mites), environmental factors (e.g., barley hull allergy, frost bite, straw mites), nutrition (e.g., vitamin A or zinc deficiencies), and mycotoxins (e.g., ergot, citrinin, T2 toxins). Objectives: The objectives of this study are to: 1. To provide insight into the cause and potential prevention/treatment of itching beef cattle in Western Canada Implications of the Research: This project will determine what factors are most likely contributing to itchy cattle in the