Domestication: When?

Recently, archaeologist Alan K. Outram of England has made discoveries that indicate an earlier than known domestication of the wild horse. He wrote of uncovering ample horse bones and artifacts from which they derived “three independent lines of evidence demonstrating domestication” of horses by the semi-sedentary Botai culture, which, beginning around 3600 B.C., occupied sites in northern Kazakhstan for six centuries. The skeletons from four sites were analyzed for their size and shape and then compared with bones of wild horses in the region from the same time period, with domestic horses from centuries later in the Bronze Age, and with the Mongolian domestic horses. Their physical features were surprisingly different which made them more useful to the people as meat, sources of milk and beasts of burden and locomotion.
The second form of evidence were the indentations  on the horses’ teeth and damage to skeletal tissue in the mouths. Archaeologists said that this was caused by the wearing of bits, mouthpieces inserted for harnessing with a bridle or similar restraint to control working animals. Similar discoveries have been made at other sites but have been disputed as support for domestication.
The exact time and location of the beginning of the domestication of the horse has eluded archaeologists. In 2007, David W. Anthony, an archaeologist at Hartwick College in Oneonta, N.Y., said that some of the best evidence put the beginning of horse domestication in the region around 2500 B.C. The question of roughly when domestication began has been answered, but what about the reason why? Who was the first to attempt to do so?
Wilford, John, N. (2009, March 06). Earlier date suggested for horse domestication. The New York Times. Retrieved from http://www.nytimes.com/2009/03/06/science/06horses.html?ref=horses