IF you've even seen a castration operation, you'll know that it's VERY difficult to NOT get the entire testicle. Imagine a yo-yo on a string. The yo-yo is the teste and the string is the spermatic chord. You remove yo-yo buy cutting the string, so the yo-yo is removed entirely. Unless there is extra displaced testicular tissue pumping out testosterone, when the chord is cut the testicle is GONE.

Some people say a horse is proud cut when he goes through stallion behaviors. There's no testicular tissue left, but for some reason (memory, learned) he still goes through the motions.

Equestrians do it with whips, spurs, and leather.

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