How essential are natural service bulls to the dairy industry?

“Most people in the dairy industry do respect and recognize the danger of bulls, but approximately 80 percent (some estimates are as high as 96 percent) of dairy farms keep some anyway,” says David Wilson, extension veterinarian at Utah State University.

“It has become widely accepted, and often appears to be true, that bulls are needed to get a substantial proportion of cows pregnant on dairy farms when A.I. has been unsuccessful many times,” Wilson writes in the May 2012 Utah State University Dairy Veterinary Newsletter. “Is this really supported by evidence?”

In the newsletter, Wilson examines the following:

  • Do bulls detect estrus so much better than humans that they are essential to getting repeat breeders pregnant?
  • Infertility, genetic inferiority, and disease transmission are problems with natural service bulls.


Source: May 2012, Dairy Veterinary Newsletter, Utah State University Cooperative Extension