Salmonella saint-paul infection in two dairy herds

An outbreak of salmonellosis due to Salmonella saint-paul in two dairy herds was first detected during routine examination of calves soon after calving; infection reached 100% amongst calves and up to 60% amongst milking cows. Excretion by cows continued for over 12 months and by calves for up to 18 months. The most important factor in controlling the spread of infection was reduction of environmental contamination by removal of carriers, prompt antibiotic treatment of sick calves and reduction in stocking densities.