Non-invasive sampling based screening of dairy cattle herds for Mycobacterium sps

Current diagnostic methods for Bovine tuberculosis (TB) and Paratuberculosis (pTB) involve invasive sampling methods that require handling and restraining causing stress and pain to the animals along with days required for the interpretation of test results. By the 3Rs ethical principle and animal welfare, an alternative non-invasive sampling method to screen herds could be a better option. Milk may be a major source for the large-scale spread of tuberculosis and to a considerable extent of paratuberculosis bacilli in humans. Keeping this in view, milk samples were utilized for the screening of herds employing acid-fast staining microscopic examination to determine the presence of Mycobacterium and other acid-fast bacilli (AFB). For the study, a total of 150 milk samples collected randomly from dairy herds of five major gaushalas of the Vrindavan and Mathura region of Uttar Pradesh, India were screened. Microscopic examination reveals the presence of AFB in 18 samples from 3 out of the 5 herds under study. In conclusion, the presence of the AFB in the milk being used for feeding calves and human consumption is alarming for both animal and human health aspects and requires confirmation on a large scale to control the further spread. Also, the study indicates the importance of milk samples microscopic examination for AFB as an alternative non-invasive procedure for initial screening of dairy herds for TB and pTB.