Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
Actinomycosis is a disease entity popularly called "lump jaw", "lumpy jaw" and "big head." It has been reported in the bovine, equine, porcine, ovine, caprine, canine and feline and generally affects one or more of the following structures: maxilla, mandible, submaxillary lymph nodes, skin (behind the angle of the jaw), tongue and udder.l The ox is the animal most often affected commonly in the area around the angle of the jaw, hence the lay term "lump jaw." In horses, actinomycosis is quite often seen in the submaxillary lymph nodes and in the spermatic cord as a sequel to post-castration infection, usually resulting in a typical scirrhous cord.
Brewer, James S.
"Discussion and Case History: Actinomycosis,"
Iowa State University Veterinarian: Vol. 18
, Article 4.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol18/iss3/4