Don't believe hornless goats exist, something you have to do or as mentioned, the person you buy them from. I like goat's milk better than cow's any day of the week, just goes down sooooo smooth!
I get mine from a lady in Summit, Mississippi. Hers are a cross of Nubian and something else, can't remember what at the moment. She has a nice little set up going, milking stalls with stainless everything except of course the milk hoses themselves.
The goats go into the stall for a bite to eat while they're being milked, its a pretty cool set up.