If you don't like killing animals or watching them die for any reason, I would suggest staying out of veterinary medicine, or, for that matter, many other animal-related careers, including working at animal shelters/humane societies.
If you don't have an iron stomach, and if you can't harden your heart to pain and death, stay out of the animal care field.
As someone who worked for years in shelters and/or as a vet tech, and whose responsibilities including euthanizing cats and dogs, believe me, if you can't harden yourself to the realities of such a world, it'll haunt your dreams and your life for decades to come.
After giving that up, I became a Special Ed teacher. I wouldn't suggest that, either. Extremely stressful, and office politics are office politics, no matter where you work.
I'd say, retire now, while you're ahead
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