Andy:
I not sure if this definitively answers your question but the contract that covered shipment of livestock was based on the Interstate Commerce Commission "Uniform Livestock Contract". I have included a section from this contract which I interpret that the shipper is responsible for the feed. You have to remember that the livestock could only be contained for a maximum of 28 hours by law so I would assume that they were fed and watered prior to loading by the shipper and then not again until they reached the next pen.
Excerpt from the Uniform Livestock Contract:
Sec. 4.
(a). The shipper at his own risk and expense shall load and unload the livestock into and out of cars, except in those instances where this duty is made obligatory upon the carrier by statute or is assumed by a lawful tariff provision. In case any person shall accompany the livestock in charge of same, he shall take care of, feed and water the livestock while being transported, whether delayed in transit or otherwise, and whenever such person shall open or close any door or opening in the car or cars, or the pens or compartments in the vessel, he shall see that the same are so closed and fastened as to prevent the escape therefrom of any of the livestock.
(b). When bedding or appliances of a character not generally in use in the transportation of livestock are required they shall be furnished by the shipper at his own expense and he shall separate different kinds of stock when loaded in the same car by adequately strong partitions and such stock shall be at the risk of the shipper as to any damage resulting from the insufficiency or inadequacy of any such bedding, appliance, or partition.