If your horse tries to bite you when you saddle him, first make sure your tack is clean and it fits your horse properly and your horse has no health problems. More than likely, though, your horse is nipping at you because of a lack of respect. How do you earn a horse’s respect? By moving his feet forwards, backwards, left and right and always rewarding the slightest try. So when your horse goes to bite you, immediately make him hustle his feet. If you’re in the barn, back him down the alleyway.
If you know he’s going to try to bite you, it’d be smart to saddle him up in the arena or in a roundpen where you’ll have more room to move his feet. As soon as he reaches back to bite you, immediately put his to work. Back him up with a lot of energy or do Lunging for Respect Stage Two. What you do doesn’t really matter, but what is important is that you hustle his feet.
If the saddle is already on the horse’s back but not cinched up, hold the saddle with one hand so that it doesn’t fall as you hustle the horse backwards.
After five minutes of moving his feet, stop and go back to saddling him again. If he goes to bite, repeat the same process. It won’t take many repetitions of you making him hustle his feet for him to realize that standing still and keeping his teeth to himself is far easier than having to work hard.
A lot of people in this situation are tempted to smack the horse when he bites. That rarely works, though. What ends up happening is the horse turns it into a game. He’ll see how fast he can try to bite you before you can whack him away.
If you teach your horse all of the Fundamentals groundwork exercises, and are thorough with each one, this biting habit will disappear. It’ll just fix itself because most horse problems are nothing but symptoms of a cause. The problem is your horse has a lack of respect and it’s showing up in the form of biting. Earn his respect, and you won’t have this issue.