Scoping for Horse-Breeding Issues

The endoscope allows veterinarians to directly view the inside of a hollow body cavity, such as a horse’s reproductive tract. Illustration provided by Dr. Patrick McCue
The endoscope allows veterinarians to directly view the inside of a hollow body cavity, such as a horse’s reproductive tract. Illustration provided by Dr. Patrick McCue

The endoscope can help veterinarians see reproductive problems in horses that they wouldn't otherwise be able to accurately diagnose. The vast majority of reproductive abnormalities in horses can be detected using common procedures. However, there are a few problems that need specialized procedures and equipment for an accurate diagnosis.

One of the techniques is endoscopy, which refers to directly viewing the interior of a hollow body cavity, such as the reproductive tract, using an endoscope.

Endoscopes are commonly used in equine veterinary medicine to observe the upper respiratory tract of horses for conditions such as roaring, displaced soft palates and guttural pouch infections. The same equipment can be used to look inside the reproductive tract of a mare or the penis of a stallion.

For Mares
In the mare, an endoscope can be used to detect intrauterine adhesions, cysts and foreign bodies, as well as inflammation, fibrosis and other abnormalities. In addition, an endoscope can be used to perform low-dose insemination. A small catheter filled with semen can be passed down a channel within the scope and the semen directly deposited onto the oviductal junction at the tip of the uterine horn adjacent to the ovary with the large preovulatory follicle.

Endoscopic examination of a mare is performed after wrapping the tail and a thorough washing of the perineum. The business end of the sterilized scope is held in the gloved hand of the operator and slowly passed into the vagina.

The scope is then passed through the cervix and into the uterine lumen. Air is pumped into the uterus to inflate the structure and allow for easy viewing of the interior. The cervix is held closed to keep the air inside the uterus. Each uterine horn is examined from the base to the tip.

Common abnormalities are endometrial cysts and free fluid in the uterus, both of which can be seen during a traditional ultrasound exam. Occasionally, significant problems are observed that cannot be detected by ultrasound or other standard procedures. Examples include adhesions or scar tissue bands that cross the uterine lumen or completely block one uterine horn, fungal or bacterial plaques, and retained endometrial cups.

Endometrial cups are normal structures of the placenta that form during early pregnancy and usually regress by 120 to 150 days of pregnancy. Occasionally, endometrial cup tissue will be retained for months in a mare after foaling or abortion and are associated with abnormal estrous cycles and infertility.

We performed endoscopy on one mare with a history of chronic infertility and discovered that the tip of one uterine horn was missing. The uterus was surgically repaired in the fall, and the mare conceived on the first breeding the following spring. We have also observed foreign bodies such as the tip of a culture instrument and glass marbles in mares. The marbles were presumably placed in the uterus in an attempt to suppress estrus.

Continue reading on America's Horse Daily to learn about endoscoping stallions.




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