Koojock,
You make an interesting point, in saying that most cattle cars were closed by the time most railroads reached the west.
But, you have to take into account, that we are talking here about the rail lines ending in Missouri, Kansas, and north Texas, not New Mexico, Arizona, Colorado or California. I believe the rail line reached Sedalia, Missouri in late 1866 or so, and Dodge and Abilene a few years after.