Pekka Hamalienen in his recent "Comanche Empire" had it that the Comanches were trading horses and mules to Americans on a scale unprecedented in history. Certainly the popular stories of rapine and pillage were most all true, but there was apparently a whole 'nother side to the Comanches generally overlooked: Pragmatic businessmen, which is why them trading cattle on a large scale to the Army in New Mexico in '73 was not unprecedented.
A whole bunch of trade by Mexicans to the Americans too. In 1840 when the residents of Linnville on the Texas Coast saw a herd of 2,000 horses approaching. They assumed it was another bunch of Mexican traders en route to the US. In fact it was Comanches and Kiowas driving that stock during their Great Comanche Raid. But the Linnville people were almost right, that herd had been stolen outside of Victoria, from Mexican traders en route to Louisiana.
Likewise Olmstead, in 1857, observed herds of Mexican horses and mules driven regularly up for trade in San Antonio and beyond, by Mexicans.
And then there were the hundreds of Mexican carretas (ox carts) and their poorly-armed owners, regularly creeping across the plains at around five to ten miles a day, throughout that whole period. Early Texas commerce rolled on Mexican ox carts, which is why the Texas Rangers responded so swiftly when certain Anglo residents of Victoria took up piracy in 1857 (AKA The Cart War). Them thieves were stepping on the wealthy merchants' toes.
