Excerpts from Jim Conrad's
from the May 19, 2007 Newsletter, issued from Sierra Gorda Biosphere Reserve Headquarters in Jalpan, Querétaro, MÉXICO
The most conspicuous breed of cow seen around here is the big, white one shown at the right.
That's a Zebu, called Cebú in Spanish, or at least a cow with a lot of Zebu in it. Zebus have more sweat glands and are more resistant to tropical diseases than European breeds, so they are famous for their ability to thrive in hot climates. Their ancestors came from India and Brazil. Zebu can be recognized by the loose fold of skin, or dewlap, sagging beneath their necks, their long, drooping ears and a conspicuous, fleshy hump over their front shoulders. The one in the picture doesn't have much of a hump but I've seen old males with enormous ones.
Regular dairy and beef cattle are known by the Latin name of BOS TAURUS. Zebus are so different from most regular breeds that in the past they were usually considered a completely different species -- BOS INDICUS. However, now all the various breeds are lumped together. That seems right, since a part of the species concept is that distinct species generally don't interbreed to produce fertile offspring, and Zebus are regularly interbred with many other kinds of cattle.
Several distinct breeds or races have been derived from Zebus. There's the Gir, the Guzerat, the Afrikaner, the Red Sindhi, the Chinese Southern Yellow and several more. Brahmans of rodeo fame originated in Texas as a result of mixing various Zebu races. You can see six Zebu breeds pastured in Mexico at http://www.cebumexico.com/razascebu.html.