I am about an hour from my horse vet and my farm call fee is just under $100, before they do anything else, my bill is already $100.
I am not a veterinarian but owned several service companies that either worked on residential or commercial/governmental properties . Even back in 1990 it was determined we needed to charge at least $130 for a service call. Our trucks when equipped with the various repair parts of the equipment we serviced cost in the $150,000 range, we also had paid our technicians. Even at $130 in 1990 we were just breaking even.
We currently use two vet practices, one does farm/ranch calls only while the other specializes in equines without farm/ranch calls who we trailer the horses to them
The vet who does make calls, he has about a quarter million dollars tied up in the rig once you start adding in the specialized equipment it carries.
Since we are in the city many would think getting a vet to come here would be difficult however being in the city the vet who does make calls is constantly criss-crossing from one side of the city to the other making passes by us several times a day
For those out at the end of some rural road in middle of no where, that visit is one of questionable income production