Mare Services - Trans-Vaginal Aspiration (TVA)
Rhinebeck Equine, LLP is proud to announce that they will be teaming up with Hagyard Equine Medical Institute this season. We will be adding trans-vaginal aspiration (TVA) to our reproductive service line. This procedure will be offered on select dates this spring.
For more information regarding this procedure, or to discuss this choice for your mare, please contact Rhinebeck Equine, LLP at 845-876-7085 or by email at [email protected].
Dr. Justin W. McNaughten, our DACT, will be available to answer any questions you may have.
In TVA procedures the veterinarian places an ultrasound vaginally and a hand rectally in the mare, bringing the ovary in contact with the wall of the vagina. This accomplishes two things:
- The veterinarian is able to visualize the ultrasound image of the ovary and
- The ovary is held tight to the vaginal wall, not allowing for any structures to be between the vagina and the ovary.
A long needle is inserted into the guide of the ultrasound handle and the needle passes through the vaginal wall and into the follicle(s) of the ovary. The follicles are then aspirated. By doing this we are able to harvest oocytes directly from the ovaries.
These oocytes are placed in a specific media and held overnight in a gas incubator to mature them. The eggs that successfully mature are then ready to be injected with a sperm cell (ICSI) to be fertilized. The injected egg is then introduced to another media, placed back in the incubator and the end result will hopefully (and often is) an embryo that is then available to transfer into a recipient mare.
Why do TVA?
There are a few different circumstances when TVA is a good option for the breeder.
- The first is ‘mare driven”.
Mares that become unsuitable to carry their own foal may also become unsuitable for embryo transfer due to uterine or cervical issues. Because this process bypasses the uterus of the mare completely, it can work very favorably with these mares; not only being the only option for some, but in most cases, being a good option.
- The other reasons are ‘semen driven’.
Two common reasons come in to play here. One is that the semen may possess poor fertility due to issues such as motility of the sperm, but the sperm may still be capable of producing fertilization (and live foals) when utilizing sperm injection (ICSI). Or there may a limited amount of frozen semen from a deceased stallion that would be able to produce few if any pregnancies utilizing normal artificial insemination but using this technique there is now enough semen to literally produce hundreds of pregnancies.