EPIDEMIOLOGY OF HEMOPHILUS-SOMNUS INFECTION IN DAIRY-CATTLE IN QUEBEC

  • 1 January 1983
    • journal article
    • research article
    • Vol. 47  (4) , 456-459
Abstract
Serological studies on H. somnus infection were carried out on 1795 cattle from 231 dairy herds in the province of Quebec [Canada]. An epidemiological investigation was done in each of the dairy operations. Seroreactivity rate and mean log2 titer for all the sera were 55.4% and 4.1620, respectively. Cattle from eastern regions of Quebec demonstrated the lowest prevalence of H. somnus agglutinins. The percentage of seroreactor animals was 60.3 in hereds of 100 cattle or more in comparison to 53.2 in herds of smaller size. About 75% of the animals from 16 herds in which .gtoreq. 1 cattle showed nervous manifestations of undetermined origin over a 1 yr period had antibodies to H. somnus. Herds in which respiratory diseases occurred had 59.6% seroreactor animals and herds in which weak calf syndrome was diagnosed over a 1 yr period had 61.4% seroreactor animals. In 87 herds located within 20 km of feedlots, 61.8% of the sera had titers and the mean log2 titer was 4.4813.