My brother is a vet. Many years ago...when he was still in vet school... my mother wanted him to neuter her new male kitty. Albert was a little young for the surgery but my brother was heading back so it needed to be done. Fortunately I am not too sensitive as my brother began to neuter the cat on the kitchen table and I had not yet finished my breakfast.
The point of the story is to the question of whether parts are removed or just the vas cut. At least I can say how it was done 20 years ago. After he was done I noticed a couple of VERY small white balls in alcohol in one of my mother's salad dishes His explanation ...which I remember to this day... was "doctors don't clean up after themselves!"