"Glass Balls Mimic Embryonic Development" -
Three equine specialist from the College of Veterinary
Medicine at Auburn University are responsible for research
presented in a paper at the 2001 American Association of Equine
Practitioners meeting in San Diego*. Their research focused on the
use of a glass ball inserted into the uterus of a mare in order to
The following interview is an excerpt borrowed from dvmnewsmagazine.com* Apr 1, 2003 -
"The size of the ball is important, and a 35-mm diameter ball seems
optimal. After adequate preparation, a sterile palpation sleeve is used
and the glass ball is passed vaginally through the cervical lumen and into
the uterine body. The glass ball can then be manipulated via rectal
palpation and moved further into the uterine body.
Correct placement of the ball at the horn-body junction can be
easily confirmed with an ultrasound examination.
Some practitioners follow placement of the ball with infusion of
antibiotic (ticarcillin at 1 gram is recommended by Nie) to help with any
possible infection. Correct sterile technique will lessen the need for
such use however.
The ball should be placed within 24 hours of ovulation. Some
veterinarians have reported that certain mares will spontaneously expel
the balls, but this is uncommon and was not observed in any of the mares
in the university study. The use of glass balls to suppress estrus provides the practitioner
with a safe, simple method of keeping some mares out of heat.
This method does not have any significant disadvantages for
immediate performance use or for long-term reproductive use. It does not
require extra-label drug use and it offers the owner a more "natural"
means of controlling a potentially difficult mare. So before you lose your
marbles dealing with that "witchy" sporthorse, consider putting one
in." DVM Newsmagazine
UPDATE; It has been suggested that the ball be removed during winter months or between cycles.