Q:My 8-year-old gelding has been diagnosed with a hernia between the omentum (a fold of the abdominal tissue surrounding the organs) and the inguinal ring (an opening deep within the groin area through which the spermatic cord passes).

I first noticed a large, hard lump (about the size of my palm) just below his stomach, on the upper part of his sheath or scrotum along with huge swelling of the sheath area which I initially thought was a hygiene issue. He has had no signs of real discomfort, his bowel movements have been the same, and he doesn’t have any problems with urination.

I have had two different vets look at it, test his blood for any abnormalities, and on the vet’s last visit he conducted both external and rectal ultrasound exams.

All bloodwork came back normal, the external ultrasound showed multiple pockets of liquid in this hard lump, and the veterinarian was unable to find the inguinal ring on rectal ultrasound. After conferring with a surgeon the vet diagnosed it as a hernia.

Of course, the surgeon said he will do another ultrasound prior to surgery since he is not the one who has actually seen my horse.

My question is, simply, are there more possibilities of what this could be, do I have enough information to schedule the surgery, and/or what more should I know/learn prior to scheduling a hernia removal surgery?

Rahna Fafnis, via e-mail

A:Sudden development of a hernia in the region adjacent to the sheath would be very unusual, unless it was associated with a surgical procedure or major trauma (such a