Why Embryos Fail and Improving Odds of Successful Horse Breeding
If entering the fall, your breeding prospect has come up empty, there are considerations to ponder and actions you can take for successful breeding next year. “Don’t let those mares sit all fall and winter, with untreated conditions such as a uterine infection,” says Dr. Tracey Chenier, Theriogenologist and researcher from the Ontario Veterinary College at the University of Guelph.
Mare licking and cleaning foal after parturition.
Older mares can have poorer oocyte (egg) quality which reduces their chances of getting pregnant and can result in higher rates of mid-gestational losses.
© 2017 by Melissa E Dockstader New window.
“Have a thorough veterinary evaluation now to help ensure her uterus is clean and she is healthy and cycling early next year, for the best chance of a positive outcome.”
Common Issues Conceiving and Potential Solutions
“The number one reason your mare didn’t get pregnant in any given year may be due to uterine infection,” says Chenier. “The term we use is endometritis.” Most often caused by a bacterial infection, it is often associated with poor perineal conformation.
In other words, your mare has a tilt to her vulva causing the vagina and uterus to become contaminated with bacteria every time she defecates. It is also common for these mares to wind suck, which can lead to infection and inflammation that results in a hostile environment the embryo cannot survive in.
A minor surgical procedure known as a Caslick’s suture reduces the chance of contamination in most affected mares. Severely affected mares may require additional procedures to reconstruct the perineal body.
Another common form of endometritis is PBIE, or persistent breeding induced endometritis. In these cases, there is a prolonged inflammatory response to semen and contamination that occurs at breeding. Again, the mare has a hostile uterine environment in which the embryo cannot survive.
To improve the chance of conception, this condition can be managed by ultrasound within 6 to 12 hours after breeding. She is checked for fluid retention and inflammation and if present, the uterus is lavaged to remove the fluid and calm the inflammation. The veterinarian may also advise administration of oxytocin to increase uterine contractions and help remove the fluid.
Another very common reason for the mare not getting pregnant is their age. “We actually consider mare’s fertility to decline as early as 12 years of age,” says Chenier, “and that surprises people that as early as 12 years, their fertility can decline significantly.” Older mares can have poorer oocyte (egg) quality. This reduces their chances of getting pregnant and can result in higher rates of mid-gestational losses.
Older mares are more susceptible to many circumstances including uterine conditions, metabolic disease, changes to the uterus, fibrosis and cysts. Fibrosis of the uterus will reduce the chances of carrying a pregnancy to term. Endometrial cysts or fluid filled sacs in the lymphatics of the uterus can block the ability of the embryo to move around and interfere with the placenta formation.
See complete information-packed article including illustrations and video HERE .
Press release by Equine Guelph