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
On Jan. 11, 1955, a yearling Standard-bred stallion colt entered the Stange Memorial Clinic for treatment. The history stated that a rupture, present since birth, had been enlarging during the past month. The patient was examined and found to have a reducible swelling on the midline just anterior to the preputial orifice with a hernial ring approximately 1% inches in diameter. A diagnosis of umbilical hernia was made.
"Umbilical Hernia in a Colt,"
Iowa State University Veterinarian: Vol. 17
, Article 10.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol17/iss2/10