These questions came to mind when I was coming up with a magical type of barding in which it allows for the usage of Fly. What would a horse do the first time such a piece of equipment were placed on him? Does being Combat Trained encompass reactions to spells? Could there be a variant that does this, such as "Magic Trained" or something? Could a horse react differently to Fly being cast upon it based on the physical description of what it does--a floating horse vs a pegasus-style evolution?
Maybe I'm reading into this too much, but I like horses. I knew a saddle before I could walk. In a desert campaign I was in, the GM let me have a bonus based on the fact that my character's mount was an Arabian. The breed has larger nostrils for ease of cooling himself down, and larger feet for staying above the sand. He's smaller and lighter, needing less sustenance than a European breed.
Any thoughts in this arena?
That's an interesting perdicament. Ussually people overlook something like the animals reaction to a spell, I know I have.
The way I see it, combat trained is specific to the actual things that it can be taught under the skill "Handle Animal". However, I think what you're putting forward would be up to the DM and the player to deem what they would see as appropiate. I think in the least, you should at least train your mount to get it used to that kind of combat (a horse doesnt know how to fly, a fish doesnt know how to fly, a bird doesnt know how to swim etc). I think the same thing would be appropiate for that kind of barding. Does that make sense?
I know in my campaign we try and see those kinds of things in perspective from the players and the things that are being affected. At one point a player animated a tree and the tree walked trough the village not knowing it would have been attacked. Long story short, the village got burned down. The tree didnt know that the people of the village would have an adverse affect to it, being as the tree knows only what a tree would know