Prevalence of and risk factors for Salmonella in water offered to weaned dairy calves in California, USA.

Water from troughs used by weaned dairy calves was sampled on California, USA dairies to determine the prevalence and associated risk factors for Salmonella contamination. Salmonella were found on 4 of 48 dairies (4/82 water samples) in fall 1998 and on 8 of the same 37 dairies (8/83 water samples) in summer, 1999. Serotypes isolated from the water were Salmonella meleagridis and Salmonella typhimurium. Primary risk factors associated with the increased prevalence of Salmonella in water offered to weaned dairy calves were a continuous water tank-filling method compared to a valve (an "on-demand" procedure) and a water pH>8.