* Think about the roles of a veterinarian: They treat animals, diagnose illnesses, and sometimes perform surgeries.
* Consider what "dead cows" implies: It means the cows are no longer alive.
Putting these together, the answer might be:
"Veterinarians deal with dead cows by performing necropsies (animal autopsies) to determine the cause of death."
Let me know if you'd like to try another riddle!