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
Not too long ago, large animal veterinarians derived a considerable portion of their income from vaccination. With the cessation of most vaccinations, some practices suffered somewhat. Most continued to do quite well because the volume of their practice increased to take up the slack. Still others felt confident enough and had ingenuity to develop herd health programs which thrived.
"Improving Reproductive Efficiency - the Veterinarian's Inroad to Agribusiness,"
Iowa State University Veterinarian: Vol. 35
, Article 7.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol35/iss3/7