title: A cross-sectional study of paratuberculosis in 1155 Danish dairy cows.
abstract: In a cross-sectional study on milk samples from 1155 cows from 22 Danish dairy herds, selected risk factors for paratuberculosis were identified. The diagnostic procedure used was an indirect enzyme-linked immuno-sorbent assay (ELISA) to detect antibodies against Mycobacterium avium subsp. paratuberculosis. A sample was considered test-positive if it had a corrected optical density >/=0. 025 (test sensitivity 71.4% and test specificity 89.7%). Of the 1155 samples, 8.8% (102/1155) were test-positive, and 19 out of the 22 dairy herds had >/=1 test-positive cows. The significant risk factors in a multiple logistic regression analysis were: Jersey versus large breeds, high parity versus low parity, the first month after calving versus other months of lactation, and a large herd size compared to a small herd size. The highest probability (37-38%) of a positive test was observed among older cows (parity >4) and tested within the first month after calving (irrespective of breed). The lowest probability (2%) of a positive test-result was observed among first parity, large-breed cows tested before calving or later than one month after.
authors.affiliation: Department of Animal Science and Animal Health, Division of Ethology and Health, The Royal Veterinary and Agricultural University, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Denmark.
authors.forename: M B
authors.initials: MB
authors.lastname: Jakobsen
authors.forename: L
authors.initials: L
authors.lastname: Alban
authors.forename: S S
authors.initials: SS
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D002417:Cattle; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007774:Lactation; D008892:Milk / Q000382:microbiology*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000302:isolation & purification*; D010283:Paratuberculosis / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D010298:Parity; D011336:Probability; D012044:Regression Analysis; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D013045:Species Specificity