What burden animals were used on the silk routes? periods?

As I know, the major burden animals were camels and horses.

Did you know that burden animals or animals of burden are also known as pack animals in some quarters of the world. It appears that in some areas only pack animals were used. In some areas on the routes, carts, caravans and pack animals were used together. The main east/west trade(China to Turkey & the reverse)began in 10th century. Routes that ferried goods and culture to India and Packistan began as far back as 300 BCE or so. Recently, thirty years ago archaeologists discovered a burial site in the general area of the Chinese autominous regeons. They uncovered graves containing caucasoid and asian skeletons. This indicates there was an early perod around 1,200 BCE where people from the far east met people from the far west; a major revelation.