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
During the first week of June, 1941, Dr. Charles Schmitt, of Dodgeville, Wisconsin, was called to relieve a dystocia in a grade Percheron mare. She had been in labor approximately three hours after a gestation period of about nine months. One forefoot and portions of fetal membranes were protruding from the vulva.
Wilson, J. W.
"Dystocia in a Mare,"
Iowa State University Veterinarian: Vol. 4
, Article 10.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol4/iss1/10