Bears undergo one-off surgery to create a permanently “open” duct or fistula from the gall bladder to the abdomen. Bile drips freely from this duct.
As the hole naturally tries to heal itself, each milking session involves poking a metal tube through the membrane that has grown over the wound to allow the bile to flow out.
Although this method is claimed to be the most “humane”, more than 20 per cent of rescued free-drip bears have infected fistulas and abdominal abscesses. Some have peritonitis caused by bile leaking into the abdomen. Bile collected in this way is also observed to contain pus and other contaminants.
This method is the only extraction method currently permitted in China and is commonly used on Chinese farms.