this is interesting. there is a critically rare breed of cattle known as the Florida Cracker Cow and the smaller version which is the Guinea Florida Cracker Cow. They are small, and extremely disease resistant, parasite resistant, heat resistant, insect resistant, and designed to forage in the harshest of scrubby Teranes (spelling?) and can live off of extremely poor food sources. The smaller ones can be as small or smaller than a dexter, and are far hardier.