I saw this information on Pulse (iPad) which is part of Linked in. The subject of Black cowboys has been written about in the West. More recently writings have highlighted organizations today from NJ to the West Coast.
Black cowboys in FL has a rich history. The link to NPR history can also be followed on twitter. It would be nice to travel to Florida to see the exhibitions on this subject. Links:
A fresh look at American history @NPR / Linton Weeks
Washington DC·NPR.org/history