The material below is Open Game Content from a 3PP Source
Ferocious Mount, Greater (Ex): While raging and mounted, the barbarian's mount gains the benefits of any rage powers that are constant in effect when the barbarian is raging. It does not gain the benefit of any rage powers that require actions to activate, even if they are free actions. A barbarian must have the ferocious mount rage power to select this rage power. A barbarian must be at least 8th level to select this rage power.