Equine and Camelid Castration
In horses, inguinal hernias are seen in babies (not usually an emergency) and in breeding stallions (an emergency). In both, the hernia is related to a vertical inguinal canal. The inguinal canal is comprised of an internal inguinal ring, an external inguinal ring and the space between them. In most adult animals, the canal is slanted, making it more difficult for things to just drop through. In geldings and mares, the rings are also very constricted. When stallions are in a breeding position, the rings are more directly lined up and intestines can slide through the canal and into the scrotum. When the horse returns to a regular standing position, the intestines and their blood supply are squeezed and will soon become strangulated. Emergency referral to a surgical facility is essential.
In babies, the inguinal canal is also vertical but the intestines do not get stuck and can be shoved back into the abdominal cavity, even though they quickly slide right back into the inguinal canal. Over time, the rings adjust position and the hernia typically resolves. Mother nature usually takes care of this without intervention. Hernia wraps (diapers) and surgery are not usually needed. However, babies should be checked on a daily basis to make sure the hernia is reducible and the intestines are not trapped. If the baby should become colicky or the intestines seem to be stuck, emergency referral is indicated.
Certain breeds are predisposed. Saddlebreds, Standardbreds, Tennessee walking horses, draft breeds and Andalusians are at higher risk.
These foals may be at increased risk of evisceration at castration so extra precautions should be considered. Closed castration, restricted exercise and having the procedure performed at an equine hospital may mitigate the risk. If you open the tunic and can slide a finger up it, the ring is bigger than usual! You can palpate the inguinal ring via rectal palpation and check it for intestines. You can also ultrasound the area if concerned.
Closure of the internal inguinal ring is challenging and not readily performed in the field.
Note: In rare cases, the intestines herniate due to trauma to the body wall. Intestines are subcutaneous vs in the inguinal ring and scrotum. This condition does require emergency surgery.
Inguinal hernias in adult stallions are concerned emergencies and often require surgery to remove entrap intestines.
What about in foals? Are these emergencies? Do they need surgery?
How do you diagnose them? How are they managed? Are there breed predilections?
How would you adjust your castration plan if you knew the horse had a history of inguinal hernia? Diagnostics? Surgical approach? Postop care?
Are they considered an inherited trait?
Try these after you do your research:
Management of inguinal hernias in foals, VetFolio, 2019
Hernias explained, The Horse, 2008
Selected pathological conditions in horses, AAEP 2015 page 272 (will link to the entire proceedings)
JUST FOR FUN
Guts being pulled out of inguinal hernia laparoscopically – not usually required but note how healthy they look