Pilot studies conducted by U of G researchers are included in a Canadian Cattlemen: The Beef Magazine [1] article on M. bovis, which can cause chronic pneumonia and arthritis in cows.
In the studies, beef calves were challenged with M. bovis alone, or with both M. bovis and a Bovine Respiratory Disease (BRD) virus or BRD bacteria. Both studies suggested that M. bovis didn’t cause significant problems on its own. But the additional inflammation caused by the other pathogen allowed M. bovis to gain a foothold and cause significant disease.
Read the article: M. bovis, repeat offender - Canadian Cattlemen [1] or the article published in the Journal of Veterinary Internal Medicine: Effect of aerosolized bacterial lysate on development of naturally occurring respiratory disease in beef calves [2]