The economic impact of Johne's disease is difficult to quantify. Although, the adverse effects of the disease in the clinical stage are well documented, its specific impacts on fertility, mastitis and milk production during the sub-clinical stage are less well documented. The aim of this study was to address these questions by comparing anti- M. paratuberculosis antibodies, tested by commercial IDEXX ELISA test kit, to milk production, between partum interval and somatic cell counts obtained from the Dairy herd book of the Israeli Cattle Breeder's Association. Statistical analysis was conducted using SAS and a regression model that included independent variables such as, ELISA results, farm, lactation and days in milk. Blood was collected from all the milking cows (n=723) in three farms. Prevalence of Mycobacterium paratuberculosis test-positive animals in the three herds was 7%, while according to the age was 1.5% for the first lactation, 7% for the second, 14% for the third and 10% for the fourth lactation period and forth. Animals recorded negative in the ELISA test during one month of study produced significantly more milk than those tested positive (p=0.01). The comparison of the previous milk recordings among the positive cows, showed more production of milk during their first, second and third lactations and less throughout later periods in. None, of these differences, however, were statistically significant. Comparison of between partum interval and somatic cell counts among the two groups showed no significant differences. It is therefore concluded that the factors evaluated in this study did not pose a significant herd problem.