This isnt really done much tbh.. not over here at least. Most milked animals are in captive laboratory collections. You would probably need to have a toxicology degree to be considered for it anyhow.
Liverpool school of tropical medicine have run various venom studies over the years if you want to get in touch with someone working in that field...
Very few places "milk to release", they tend to keep the animals for longer periods milking on a regular basis.
Milking to release is usually done on those animals that are rare and part of s specific study.
I have no idea which country you're in but i'd suggest the best places to look at are the eastern countries or scientific establishments.