Cut ears

Have you ever had her out running in a field that doesn't have briars? If so, was their the same bleeding? Dogs have blood vessels in their ears and I believe a big reason for the blood vessels is to help cool the dog.

I am wondering if her ears would bleed if she just ran for a while without the briars. Could it be that when the blood starts pumping fast, could she just have weak blood vessels in the end of her ears? Maybe the cuts started from briars and like a scab, the would opens when the blood starts pumping?