Sentence:  ... sette him vppe, and tye him in his bridle to the bare Racke, and all to rubbe and chafe him, insomuch that if hee be eyther wette with sweate or any other thing, you leaue hym not till he be as dry as may be, then <WSD>vnsaddle</WSD> him, rub hys backe thorowly ... 
Meaning of the word marked with <WSD> tags:  To remove a saddle.