I have the pocket notebook of Cyril B. Carpenter, the general superintendent of the Rio Grande Southern from 1917 to 1923 and long-time D&RG executive. He used the book as a sort of “I Pad”, keeping information on details of how to run a railroad. Here is what he had to say about cattle cars:
Live Stock Loading, depended upon the weight of the animals but averaged on the narrow gauge: hogs: 90 head per car
Sheep: 160
Cattle: 20