A hard tick found most often on cattle, heavy burdens of which decrease milk production and damage hides. R annulatus is also a vector for babesiosis–due to Babesia bigemina and B bovis, and anaplasmosis–due to Anaplasma marginale.
Epidemiology Cattle are the preferred hosts for R annulatus, but in a pinch, it harries horses, disturbs deer and torments sundry ungulates. It is a one-host tick and spends all stages on one animal. The eggs hatch outside the host. Larvae crawl up grass or other plants to find the next host.
Synonyms Boophilus annulatus, Margaropus annulatus