In what areas should you have strong knowledge to be a veterinarian?

Veterinarians have a broad range of knowledge, covering everything from the fertilization of an egg at conception to performing a necropsy on a dead animal, all levels of complexity from the molecules in the cell to the interactions of the organs in the entire animal, and from a single isolated animal to the world's population of animals and how they interact with the plants, humans, and other animals in their environments.