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
April 13, 1945, a spotted Morocco stallion, age 3 years, was presented at the Stange Memorial Clinic for castration. The right testicle was found to be in the normal position, but the left testicle could not be palpated in the scrotum. A diagnosis of cryptorchidism was made and the animal was operated on accordingly. At the time of the operation, a mass of scar tissue and the absence of a pronounced testicle in the abdominal cavity indicated that the area had been previously entered. The right testicle was removed however, and the animal was discharged May 6, 1945.
Skewes, Art and Neumann, A.
"An Extended Case of Cryptorchidism in a Horse,"
Iowa State University Veterinarian: Vol. 10
, Article 13.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol10/iss2/13