Found some stuff: gelding, neutering, orchiectomy, orchidectomy, and oophorectomy. And:

* Barrow (pig)
* Bullock (cattle)
* Capon (chicken)
* Dinmont (sheep, goat)
* Gelding (horse)
* Gib (cat, ferret)
* Havier (deer)
* Lapin (rabbit)
* Stag (cattle, sheep)
* Steer (cattle)
* Wether (sheep, goat)

And check the link http://en.wikipedia.org/wiki/Castration to read under "Castration in Humans", the last paragraph about China. Oooph!!!