Risk factors for fecal shedding of Salmonella in 91 US dairy herds in 1996 E.K. Kabagambe a,* , S.J. Wells a , L.P. Garber a , M.D. Salman b , B. Wagner a , P.J. Fedorka-Cray c a Centers for Epidemiology and Animal Health, United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, 555 S. Howes St., Fort Collins, CO 80521, USA b Centerof Veterinary Epidemiology and Animal Disease Surveillance Systems, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80521, USA c United States Department of Agriculture, Agriculture Research Service, Richard Russell Research Center, Poultry Microbiology Research Unit, 950 College Station Rd., Athens, GA, 30605-2720, USA Received 6 April 1998; accepted 16 September 1999 Abstract In 1996, data on management practices used on US dairy operations were collected and analyzed for association with fecal shedding of Salmonella by dairy cows. A total of 4299 fecal samples from 91 herds was cultured for Salmonella isolation. Herd-size (adjusted odds ratios (OR)  5.8, 95% CI 1.1, 31.3), region (OR  5.7, CI 1.4, 23.5), use of flush water systems (OR  3.5, CI 0.9, 14.7), and feeding brewers' products to lactating cows (OR  3.4, CI 0.9, 12.9) were identified as the most important predictive risk factors. The population attributable risks (PARs) for herd-size, region, flush water system, and feeding brewers' products to lactating cows were 0.76, 0.46, 0.37, and 0.42, respectively. The estimated PAR for all four risk factors combined was 0.95. The effects of these factors need to be more-closely evaluated in more-controlled studies, in order to develop intervention programs that reduce Salmonella shedding. # 2000 Elsevier Science B.V. All rights reserved. Keywords: Salmonella; Shedding; Herd level; Cattle; Risk factors Preventive Veterinary Medicine 43 (2000) 177±194 * Corresponding author. Present address: Department of Epidemiology and Community Health, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA. Tel.: 001-225-346-3335; fax: 001-225-346-3331. E-mail address: ekabagambe@yahoo.com (E.K. Kabagambe). 0167-5877/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved. PII:S0167-5877(99)00094-X