Detection of Paratuberculosis in Breeding Bulls at Pakistani Semen Production Units: A Continuous Source of Threat

Paratuberculosis is a chronic bowel disease of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). Its secretion through semen highlights the importance of paratuberculosis-free breeding bulls. The breeding and teaser bulls at three semen production units (SPUs) located in Punjab, Pakistan, were screened for the presence of antibodies against MAP. A total of 253 samples were collected from SPUs and a commercially available indirect screen ELISA (Is-ELISA) was applied. Is-ELISA detected antibodies in 20 (24.6%), 16 (22.8%), and 17 (16.6%) samples from SPU-I, SPU-II, and SPU-III, respectively. Collectively, seroprevalence of 20.0% (47/235) in breeding bulls and 33.3% (6/18) in teaser bulls was observed, and thus it poses a potential threat of disease spread to a high number of heifers and cows through artificial insemination. Therefore, this paper highlights the presence of the disease for the first time at SPUs and triggers attempts to ascertain the prevalence of paratuberculosis throughout the country.