Packhorse

Finally they put him on one of De Soto's packhorses, but even on a packhorse his feet hung down to within a few inches of the ground.

Source: wiktionary

Procter had a handsome half-breed girl with him and two splendid elk heads and meat on his packhorses that he was taking to Fort Lincoln for sale.

Source: wiktionary

While I was destroying my parka, the packhorse that Bob had been leading laid down. So now all our supplies were supine along with the napping packhorse. Looking upon a reclining packhorse while facing a wind-driven rain, wearing a tattered rain parka, with lightning flashing every fifteen seconds followed by thunder so loud my clothes shuddered was not how I had expected the afternoon to unfold. Each time we got the packhorse to his feet he would promptly lie down again.

Source: wiktionary