A Bovine practitioner survey of Johne's disease

Abstract

A questionnaire survey was conducted among veterinary surgeons to determine the prevalence of Johne's disease in their practices. A total of 2755 questionnaires were sent out and 799 (29%) were returned. For the 5 year (1973-1978) period, 2148 confirmed and 3037 suspected individual infected cattle were reported. In addition, 608 confirmed and 1098 suspected Johne's disease infected herds were identified. An estimated adjusted herd infection rate (confirmed infected herds only) of 4.3 per 1000 herds was calculated for the period. The highest infected herd rate was reported from Virginia, Pennsylvania, Delaware and Maryland. Several other districts had similar infection rates. The lowest infection rate was from the Great Plains and Rocky Mountain states. The incidence rates were highest in regions of high cattle density and where cattle are confined suggesting that these factors increase the risk of Johne's disease transmission. There were more reported individual infected cattle in Holsteins than in any other breed; however, the breed population data were not available for calculating breed specific incidence rates.