1) Mexican packsaddle 
• (n.) A kind of pack saddle used in the American military service and among the Spanish Americans. It is made of leather stuffed with hay, moss, or the like.
A`pa·re'jo noun [ Spanish ] A kind of pack saddle used in the American military service and among the Spanish Americans. It is made of leather stuffed with hay, moss, or the like. 
An aparejo is a kind of American packsaddle made of stuffed leather cushions.
A large, padded packsaddle designed to handle awkward, heavy loads. Very likely the first type of packsaddle, Unlike the sawbuck, panniers cannot be handled with this saddle.
a Mexican packsaddle formed of stuffed leather cushions.