Factors associated with the spread of clinical vesicular stomatitis in California dairy cattle.

: In 1983, vesicular stomatitis entered the state of California through infected cattle purchased in Idaho and sold to 5 California dairies. This study examined management, environmental, and host factors which were thought to be associated with disease spread. The use of coarse roughage and hard-pelleted concentrates, the presence of uneaten feed potentially contaminated with virus-laden saliva, increased interpen movement of cows, poor ground surface conditions, poor milking hygiene, and poor teat sanitation were management factors observed to be associated with clinical signs. The amount of milk production, age, or days in milk of individual cows seemed to have an important role in the spread of clinical disease. Recommendations are given for control and prevention of clinical signs and, therefore, the severity of disease during epizootics of vesicular stomatitis in California dairies.