D3012: Abundance of American dog ticks, Dermacentor variabilis (Say), on Manitoba cattle pastures in relation to favorable environmental characteristics and tick-cattle interactions

The geographic distribution of American dog ticks (ADT), Dermacentor variabilis (Say), has expanded north and west in the Canadian Prairies over recent decades, leading to potential risks to beef cattle and production workers in those areas. Higher abundance of ADT may increase tick-cattle interactions occurring in the pastures, raising concerns for the transmission of tick-borne pathogens such as Anaplasma marginale, the bacteria causing bovine anaplasmosis in cattle. Four sites running active cow-calf operations in Southern Manitoba were chosen for sampling of the environment and the grazing cattle to establish ADT abundance and biting pressure. Environmental characteristics were recorded in each pasture. Cattle were checked for ticks throughout their time on the pasture, with multiple individual cows from each herd being fitted with GPS collars to monitor the herds movements throughout the environment. Cattle preferring areas that have environmental characteristics ADT also prefer increases the chance of tick-cattle interactions. All ADT collected were tested for the presence of Anaplasma marginale by Polymerase Chain Reaction (PCR) assay. None of the ADT collected were positive for the bacteria. While no pathogens were detected in the ticks collected, it is important for producers to understand the risk that the presence and high abundance of ADT in their areas may pose to their animals.