Ear droop and stertor in dairy calves associated with Mycoplasma bovis

WE would like to report an unusual case of pharyngeal disease in dairy calves associated with Mycoplasma bovis . The case occurred in a closed, 290-cow, Holstein dairy herd in north Yorkshire. In February 2013, veterinary attention was sought to investigate illthrift among a group of 25 dairy calves, aged between two and six weeks. Further investigations and clinical inspection over the next five months revealed that, during this period, 10 calves in that age group developed drooping of one or both ears, with or without an aural discharge, and a further six to eight calves developed stertorous breathing or barking, emanating from the upper respiratory tract. Two affected heifer calves died and six Holstein bull calves were euthanased on humane and financial grounds. In June 2013, the upper respiratory tract from one of these euthanased bull calves …