Undescended Testicles (Cryptorchids)
Every once in a while a male puppy will have only one testicle in the scrotal sac instead of the normal two. Or none.
In the normal pup, the testicles develop in the abdominal cavity but within a few months (usually just days) they descend through the inguinal opening and make their way into the scrotal sac.
This is more common in toy breeds and is an inherited trait. For this reason alone, we encourage castration; to prevent this trait from being passed on. But there’s another reason: Dogs with an undescended testicle are much more likely to develop future testicular cancer.
The only problem with castrating these guys, though, is sometimes we can’t easily find or get to the undescended testicle... at least not without making an incision into the inguinal ring and going into the abdominal cavity ... a much more involved surgery than the typical castration.
Here’s the deal:
If you don’t do anything at all, you may luck out and the second testicle will eventually come out. This is a reasonable approach for pups up to 6 months of age, but after that, forget it. You risk both future testicular cancer and passing the problem along to future generations.
If you castrate the descended testicle, but leave the undescended one ... usually because your vet couldn’t find it without doing major abdominal surgery...it’s safe to assume that the undescended testicle will be sterile, but it may very well produce testosterone and all the behavioral problems that goes with it. And again, there’s a higher chance of future testicular cancer if an active testicle is left in the warm environment of the abdomen.
Sometimes the undescended testicle is not active ...apparently it just never developed much... and there’s no problem with leaving it alone. One way to tell is to wait until after puberty and see what happens. If your pet starts lifting it’s leg and marking every tree and so forth, despite having had it’s one exposed testicle castrated, then it’s a good bet there’s an active testicle in the abdomen and you should consider surgical removal despite your frustration in “having to pay for the same surgery twice”! I guess you have to expect imperfections in life...I know my wife does.
In any event, your vet will give you several choices, but in general, it’s best to get the job done, despite needing more extensive surgery, to prevent future problems.