title: Management-related risk factors for M. paratuberculosis infection in Michigan, USA, dairy herds.
abstract: A cross-sectional study was conducted from June through December 1996 to identify management-related risk factors for herd-level M. paratuberculosis infection. Data were collected from 121 participating herds. A two-part questionnaire was administered to gather data on current and previous management practices and herd productivity. A random sample of cows aged > or = 24 months was selected from each herd and tested for antibodies to M. paratuberculosis using the IDEXX Antibody ELISA (sensitivity 64%, specificity 96%). A positive herd was one in which > or = 2 animals tested positive for antibodies to M. paratuberculosis. A negative herd was one in which no animal tested positive. Herds in which only one animal tested positive were dropped from statistical analysis to reduce the risk of including false-positive herds in the statistical analyses. There were 80 herds with one or more positive animals and 41 herds with no positive animals in the sample (66% herd-level prevalence). Twenty-six herds (21%) were dropped from further analyses because they had only one positive cow. Twelve herds (10%) were dropped from analysis because of missing data. The resulting sample used for statistical modeling included 46 positive herds and 37 negative herds (55% herd-level prevalence). A multi-variable logistic-regression model was used to evaluate the results. The variable 'use of an exercise lot for lactating cows' was associated with a three-fold increase in odds of a herd being positive for M. paratuberculosis infection (O.R. = 3.01, C.I. = 1.03-8.80); 'cleaning of maternity pens after each use' was associated with a three-fold reduction in odds of a herd being positive for M. paratuberculosis infection (O.R. = 0.28, C.I. = 0.08-0.89); 'application of lime to pasture areas in 1993' resulted in a ten-fold decrease in odds of a herd being positive for M. paratuberculosis infection (O.R. = 0.10, C.I. = 0.02-0.56).
authors.affiliation: Population Medicine Center, College of Veterinary Medicine, Michigan State University, East Lansing 48824-1316, USA.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Johnson-Ifearulundu
authors.forename: J B
authors.initials: JB
authors.lastname: Kaneene
mesh_terms: D000704:Analysis of Variance; D000822:Animal Husbandry; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000276:immunology; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016015:Logistic Models; D008824:Michigan / Q000453:epidemiology; D010283:Paratuberculosis / Q000453:epidemiology* / Q000276:immunology; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D000907:Antibodies, Bacterial