How do you prove value on a home raised horse?

The horse is 6 and just started running this year. Between my dad and I we have put a lot of training on this horse. How do you prove training cost if you didn't send them out? He's also had quite a bit of outside training but that is easy to add up. 

Also, major medical. How do you decide to get it or not? 

Bump

I care mostly about major medical. Most companies give you a choice for $5,000 or $7500.  

To prove value on my yearling, I added up stud fee, vet fees and other costs in getting him here. 

I use Broadstone Equine Insurance. I have policies with Hartford.  They've allowed $5,000 MM without having a huge mortality policy.