Hyomashi was to manage maki (the ground to raise horses and cattle) nationwide, war-horses, cows and horses of public and private (official duty of Meryo [Bureau of Horses] that had close characteristics to Hyomashi was mainly to feed the animals in the Imperial Court) and post horse system.
兵馬司は、全国の牧、軍馬、公私におけるウシ・ウマの管理（近い性格の機関である馬寮は、主に朝廷での飼養を職掌としていた）、駅伝制などをつかさどった。