We got a call at 12:15am that our leased mare, Ibiza, had just delivered a bay colt by The Master’s Touch. Mom and baby are well. I only have a few photos at the moment, but here he is!

I recently heard about the use of a sterile marble placed in a mare’s uterus to simulate pregnancy. Apparently this is done in order to suppress the estrous cycle so that you don’t have to deal with the behavioral problems that frequently accompanies the mare’s heat cycle. I thought that this might be a way to, in effect, geld a mare, and wondered if this had been studied scientifically.

The first person I asked was the person who answered the phone in my equine vet’s office, who had heard of the technique and referred to it as an “Urban Legend”. My vet suggested that I check the internet, as he too had heard of it, but didn’t know much about it. So I googled “uterine marble, horses” and got a list of 35000 references. Many on the first two pages were references to online chats from 2005. There was one reference to a scientific vet article which I could buy for 32 dollars. Something that I did not do.

What I took away from my little research project was that this is a technique that has been used,but it didn’t appear to have any benefits over the use of Regumate for the same purpose. It is best done by an equine vet who specializes in reproduction and requires timing in the natural or HCG-induced cycle similar to the timing for artificial insemination, and is guided by ultrasound. At best, the effects may last for 2 to 3 months, if the mare doesnt slip the marble. It appears to be reversible as the marble is able to be manipulated out of the uterus via rectal palpation.

My conclusion is that this technique falls into the category of alternative medicine. It’s not really dangerous, but the effects are not reliably reproducible to the degree that it can be recommended for general use. With the use of a vet, ultrasound, and perhaps HCG, it would be expensive. If you want to spend the money to try it, you won’t do any harm, but you may not do any real good either.

Does anyone have any real-life experience with this technique?