First of all. There is no need to be concerned about having taken business classes. MBA programs are not just for people who have a BA in business. People who have all sorts of diverse bachelors' degrees start MBA programs having never taken another business class.
I'll try and give you a synopsis of my application:
GPA 3.65
GRE verbal 570 Quant 630 Analytic 5.0
Vet/Animal experience: county shelter vet hospital, humane society, critical care foal team, research, therapeutic riding, small animal hospital, asst coordinator with animal disaster response org, horse rescue, retail pet store manager. I spent three years in most of these experiences.
Other volunteer work: hospice volunteer, tutor for homeless children, college peer advisor
Business experience: paralegal, retail manager
I think the essay is an important part of the application. I was very clear about what I had learned to date from my business experience and how it applied to a veterinary practice. I also pinpointed areas I needed to increase my knowledge and how this knowledge would benefit a practice.
Hope that helps.