I have never had a vet not know what breed my dogs are, even though when I got my first one they did not have any others in the practice. My vet immediately began reading up. And when I gave her info, she listened.
Foxtails can be very nasty and a vet that lives in an area with them should know you have to REMOVE IT before your dog will get better. So I join the others in begging you to get another vet.