Hello friend,
Here's an explanation of what EVA means and more important information you need to read before you buy.
http://209.85.165.104/search?q=cache:C1X4QqiNuNEJ:www.ag.state.ut.us/animind/EVAStallionRegistryForm.pdf+EVA+stallion&hl=en&gl=us&ct=clnk&cd=2
Depending on what state the horse is in you will find there's qualifications and forms for horses with an EVA status.Your seller will be able to explain more.
Let me know please if you need more help.
Sincerely,Don
owner
multiple pet experience,I work to meet your needs