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 June 22, 1942, a purebred Holstein heifer calf was presented at the Stange Memorial Clinic. The calf was one day old and she had been straining and bawling since birth. She showed symptoms of abdominal pain, uneasiness, and no feces had been passed.
Rawson, D. W.
"Atresia of the Anus and Rectum and Recto-vaginal Fistula in a Calf,"
Iowa State University Veterinarian: Vol. 5
, Article 14.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol5/iss2/14