When you summon a riding dog or a horse, namely the celestial and fiendish varieties with Summon Monster I and 2, do you summon it with a saddle, or without?
What purpose do these animals serve on their home planes before you summon them? If the celestial riding dog was a mount to a small planar creature, and you summon that one, does it come with the saddle that may have been in use? Or, no?
The creatures summoned with Summon Nature's Ally are likely wild horses and wild dogs, but do we believe this to be the rule for all planar animals? Are celestial horses predominantly wild, and not tamed by celestial natives? What of Fiendish horses?
They do not appear with any equipment.