Colonial horse breeding regulations attempted to manage and classify equine difference, but conceded to the numerous challenges in establishing desired physical traits. Likewise, emerging feral horse herds challenged narratives of Spanish domination over colonial environments. Importantly, these feral horses were a direct product of Spanish husbandry methods that used both controlled and uncontrolled breeding. In this sense, both the free-ranging horses and selectively bred colonial horses illustrated the limits of domestication in their diverging from human efforts to intervene and control them.