Case-control study of an outbreak of clinical disease attributable to Salmonella menhaden infection in eight dairy herds.

Objective: To identify risk factors associated with Salmonella menhaden associated disease in adult dairy cows during an outbreak in California.
Design: Case-control study.
Sample Population: 8 case dairies that had > or = 1 adult animal that had clinical signs of salmonellosis and from which S menhaden was isolated and 22 control dairies, 16 of which were matched on the basis of herd size and county and 6 of which were matched on the basis of herd size, county, and breed (Jersey).
Procedure: A questionnaire was developed and reviewed with the herdsman or owner of each dairy. Primary areas of concern were herd management, disease characteristics, and feed-related information.
Results: Use of 1 particular feed mill and feeding animal fat were significant risk factors for clinical disease attributable to S menhaden infection.
Clinical Implications: Feed should not be overlooked as a potential source of Salmonella organisms in dairy herds.