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
One of the most frequent and economically important arrests in development in swine is cryptorchidism. This is a condition in which one or both testicles fail to descend into the normal position in the scrotum. Its frequency of occurrence in hogs is illustrated by reports from federal inspectors-in-charge at various packing centers in the United States which reveal that 10 to 30 cryptorchids are found in each 10,000 head inspected .. This is a significant figure when one considers that the average monthly receipts in Chicago alone are 480,000 hogs.
Reinhart, V. M.
"Intra-inguinal Cryptorchidism in Swine,"
Iowa State University Veterinarian: Vol. 6
, Article 12.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol6/iss4/12