Hasle et al. Acta Veterinaria Scandinavica 2010, 52:55 http://www.actavetscand.com/content/52/1/55 Page 3 of 9 Materials and methods The study area consisted of farms with cows that were pastured in wooded areas within the previously estab- lished distribution of bovine babesiosis [29]. Twenty- four farms scattered along most of the southern Norwe- gian coast west of the Oslo Fjord (Figure 1) were included in the study. Farms using hillside or wooded areas for pasturing were identified with the help of local agricultural authorities. None of the farmers who were asked to participate in the study refused. All the farmers confirmed that ticks occur on their farms, and the cattle were pastured on the property. All of the 306 cows included in the study were healthy and at least one year old when tested. On one farm (Farm 23), all the cows had been purchased one year prior to the study from various inland localities and had been pastured for just one season at this farm. I. ricinus is distributed mainly near the coast in this part of Norway. The study Figure 1 Map of Vest-Agder, Aust-Agder and Telemark counties, with study localities numbered from west to east (Table 1). Farm number 24 is in Vestfold County. (Copyright, map basis: Cappelen Damm as.).