From what my chiro says, since he's a sports and auto accident rehab chiro, he has studies plastering his office walls describing how ANY injury to the brain is a concussion. Even mild dizziness and headache would indicate concussion no matter what even if it may be mild. What one person has experienced a mild symptoms of a concussion to the head/brain but turns out safe and relatively uninjured (even a headache is injury), may absolutely be 100% different than a person experiencing the same symptoms but having a very serious injury.

ONLY the appropriate tests by medical staff should make the determination if she IS ok or not ok. I would go to the ER if I was 1. kicked in the stomach and 2. hit my head via horse. I have too much to lose to not go. And BTW, some emergency fees at our hospitals in Canada aren't covered by medical unless you have extended but I know it's still not the same as you guys.
I coulda sworn Cali mentioned her employer started her on the group benefits just after she started there...