The biomedical sciences are a completely empirical endeavor: it’s all about experiments and it has rather little to do with textbook learning.
You simply cannot get a meaningful understanding of how science works solely through coursework, even if your performance after four years is outstanding.
Research experience is an unwritten requirement for graduate school, and it can help for medical school and veterinary school admission. It will also be decisive for your employment prospects after four years.
In short, you should get research experience!