They will go underground and take cash.
Black market medicine: a new growth industry.
As for going underground, at some point we just might end up with new veterinarians who were former “People” docs practicing on a greatly increased pet population.
“Yeah Doc, my um... ‘Dog’ (wink-wink) has had a persistent cough, sinus infection and chest congestion for the past couple of weeks. Do you think we could get Rover (wink-wink) a course of antibiotics?”
This is starting to look like the plot of a book, a quite good one, during the 1970s. Blade Runner by Alan E. Nourse.