Horses

I am just reading Seabiscut (a pretty good read for a non-railroad book!), and it got me to thinking. Turns out horses got shipped around a fair amount, and for long distances they rode the rails. Durango had a fairgrounds, and they must have had horse races there. Surely some race horses must have traveled the narrow gauge?
I note in the 1941 and 1948 traffic reports there is a class/ rate for "horses, mules, ponies." None of the lines reports more than 1-2 carloads, so this was not a major revenue source. I wonder too if a carload of ranch horses occasionally got shiped to the high country?
For modelers, it is a good excuse to run the occassional stock car alone in a non-stock rush train.