I understand that, but a nipple is not proof of sex on a cow.
I've been checked in Colorado, Wyoming and California and nipples are good as long as they are attached to an edible piece of meat. It is very easy to tell the difference between nipples on does and bucks. Size mostly and also even tho they may not have a fawn, most are not totally dry and will have traces of milky fluid. I usually leave enought skin attached (almost as far back as the anus) along with the nipples, that anyone can see it doesn't have any male organs. You don't need any evidence of sex on an either sex tag.
Cowboy Action Shooter; Endowment Life Member-NRA
The Original Rocket Scientist-Retired
"My Father always considered a walk in the mountains as the equivalent of church going."