Prevalence of Salmonella spp in cull (market) dairy cows at slaughter

Objective-To determine the prevalence of Salmonella spp in the cecal-colon contents of cull (market) dairy cows at slaughter because of potential publ ic health ramifications. Design-Survey study. Sample Population-Cecal-colon contents collected from 5,087 cull (market) d airy cows at slaughter at 5 slaughter establishments across the United Stat es. Procedure-During 2 periods of the year, winter (January and February) and s ummer (July through September), 5 cull (market) cow slaughter establishment s in the United States-west (WE), southeast (SEE), central (CE), north cent ral (NCE), and south central (SCE)-establishments were visited, and cecal-c olon contents of cull dairy cows were obtained at the time of slaughter. Sa mples were examined by microbiologic culture at a single laboratory for Sal monella spp. Results-Salmonella spp were detected in 23.1% of cecal-colon content sample s from cull dairy cows across the 5 slaughter establishments. The highest s ite prevalence (54.5%) was detected at the WE during the summer period, whe reas the lowest was found at the CE during the summer (4.3%) and at the NCE during the winter (4.5%). Considerable variation in the daily prevalence o f Salmonella spp was found, particularly at the WE and the SCE. Salmonella spp were isolated from 93% of cecal-colon contents collected on a summer da y at the WE. Conclusions and Clinical Relevance-Results strongly suggest that there is a high prevalence of Salmonella spp in cull dairy cows at slaughter, which c ould burden Hazard Analysis Critical Control Point programs implemented in slaughter establishments. Procedures to reduce Salmonella load at the dairy farm and during transport to slaughter could reduce the risk of spread dur ing the slaughter process.