Risk factors for fecal shedding of Salmonella in 91 US dairy herds in 1996

In 1996, data on management practices used on US dairy operations were coll ected and analyzed for association with fecal shedding of Salmonella by dai ry cows. A total of 4299 fecal samples from 91 herds was cultured for Salmo nella 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 wat er 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 eva luated in more-controlled studies, in order to develop intervention program s that reduce Salmonella shedding. (C) 2000 Elsevier Science B.V. All right s reserved.