what I read was thet the zebra was on "vacation" on some ranch and got pregg by a horse......... or the other way around....... I´ll have to read the link I posted

anyway.... not planned.........although I´ve read on other sites that say they do plan crossing zebras with horses to make their back more strong for human riding abilities ......... just like with mules

I´ve seen a few zebra horse crosses but mainly they are a brown horse with stripes......