Mastitis in a 7-week old calf caused by Mycoplasma bovigenitalium.

This is the first report of an intramammary infection caused by Mycoplasma bovigenitalium in a 7-week old Holstein calf. The calf was initially presented for a non-weight bearing lameness in the left hind limb. The clinical examination revealed not only a septic arthritis of the tarsus but also an infection affecting the right rear mammary gland. The source of M. bovigenitalium was not found but the most likely explanation is spread from the infected left tarsus. This case report demonstrates that mycoplasma mastitis can occur in pre-weaned calves, which could play a role in the epidemiology of mycoplasma mastitis in dairy herds.