Thursday, March 1, 2012
All that to say that twin pregnancies in horses are not good. As a result, when we encounter twin pregnancies early on, we attempt to reduce them to a single pregnancy. Early pregnancy diagnosis with ultrasound is key to successfully managing twin pregnancies. This is one of the primary reasons to pregnancy check mares 14 days after ovulation. When the vesicles are small (less than 1.5 cm), like they are in this image, one of the pregnancies can be ‘pinched’ off with pretty good success. With one of the vesicles pinched off, the other one can go on and develop into a normal healthy foal, just as if it had started as a single pregnancy.
One of the questions we are often faced with when pinching twins is, which one do you pinch? The rule of thumb is to pinch the smaller one. Inevitably, halter horse people want the one that is a colt pinched, performance horse people want the filly pinched and paint horse people want the one without color pinched. Unfortunately, we don’t yet have the technology to easily distinguish those factors so we usually just try to do the smaller one.
Early diagnosis of twin pregnancies is key to success. If not identified and pinched early, there are other options for reducing them to a single pregnancy, but those options are much more complicated with much lower success rates.