In a herd with bovines by Mycobacterium bovis and Mycobacterium avium subsp.paratuberculosis of clinical diagnostic of diarrhoea, 137 Brangus bovines from a Buenos Aires, province farm, where tuberculinized, using the tuberculin technique of Delayed-type hypersensitivity (D.H.T.) with Bovine P.P.D., 1 mg/ml, (32.500 U.I) and Avain P.P.D., 0.5 mg/ml, (25.000 U.I.) a prevalence of 45.9% for Paratuberculosis and 27.0% for Tuberculosis were detected. The interpretation of the Comparative Test is base on the size of the response to the bovine tuberculin compared to the avian tuberculin. At the herd level, the scattergram is used for the interpretation of the results of Cervical Comparative, classifying the animals in different groups. The AGID method indicated 267 negative sera and 35 positive sera for paratuberculosis. The bacteriology isolating from four bovines in Herrold medium with mycobactin were obtained from the mesenteric lymph node, ileum caecum value, caecum, ileum, rectum and faeces. The analysis of sera using the ELISA, ELISA absorption with Mycobacterium phlei, gamma interferon and tuberculin tests, gave results that were coincident and discordant with relation to the positivity and negativity of the samples for there two diseases. The apparence of Mycobacterium bovis and Mycobacterium avium subsp. paratuberculosis in a herd, a situation that is frequent in some regions, represents a problem for a diagnostic that require great effort towards the management and control of these diseases.