Blood samples were collected from 1806 pregnancy-tested cows from 174 herds
at a northern Alberta auction mart in the fall of 1998. One hundred sixty-
two (9.0%) of these samples were positive for antibodies to N. caninum. Thi
rty-five of 260 samples (13.5%) collected from the same region in the 1980s
were also serologically positive for N. caninum.