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 Oct. 5, 1947, a Shorthorn heifer, approximately 2 1/2 years of age, was admitted to the Stange Memorial Clinic. She had been in labor since the morning of Oct. 4. The local veterinarian, who first attended the case, had advised the owner to bring the heifer to the veterinary hospital.
Archer, Jean N. and Tillie, John E.
"Dystocia Due to Induration of the Cervix,"
Iowa State University Veterinarian: Vol. 10
, Article 12.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol10/iss1/12