Incidence of clinical anaplasmosis in cattle in the Red River Plains and south-east areas of Louisiana.

Incidence rates for clinical anaplasmosis were estimated for dairy and beef cattle in the Red River Plains and South-east areas of Louisiana. Annual incidence rates of 0.33% and 0.21% were found in dairy cows for 1983 and 1984 while a 31.0% rate was found in beef cows for 1983. The rates were based on postal surveys of dairy and beef cattle producers. A survey of veterinary practices and a follow-up of respondents to the surveys provided a description of 256 cases of anaplasmosis. Eighty-one percent of the clinical cases occurred in cattle aged 4-6 years and 88% of the cases occurred during the months of July-September.