Scoping for Horse-Breeding Issues

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.

The endoscope is a tool with a variety of uses, including performing low-dose insemination in mares. For more information on artificial insemination, check out AQHA’s FREE AI Fact Sheet.

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.

Low-dose insemination in mares is just one of several uses for the endoscope. If you’re curious about artificial insemination, check out AQHA’s FREE AI Fact Sheet.

For Stallions

Endoscopic evaluation of a stallion is most commonly performed to determine the source of bleeding in a stallion with blood in his semen. Stallions that bleed during live cover or during semen collection might have a lesion on the outside of their penis on either the glans penis or on the urethral process, or might have a problem internally with either a tear in their urethra or an infection of a seminal vesicle. It is usually fairly easy to diagnose either an external penile lesion or seminal vesiculitis. Endoscopy is often required to confirm the presence of a urethral tear. A narrow endoscope can be passed up the urethra of a sedated stallion all the way to the urinary bladder. Urethral tears usually occur at a predictable site. Confirming the problem can allow a veterinarian to make sound treatment and management recommendations. Because of the high initial cost of the equipment, endoscopy is used primarily in specialty practices and referral hospitals. Consult your equine veterinarian if you have questions about a mare or stallion with a potential reproductive problem that might require endoscopy.