all, right...I was halfway through a really long posting and IE killed it. AURGH!!!
He's been handled a lot and sounds like he's developed some bad habits, so you have an uphill treck. Keep in mind that you are changing the rules of his world, so he'll be confused for awhile.
First, keep in mind that you can get his respect without teaching him to fear people. Watch a herd of cows and you'll see that they are very physical with one another, especially when they are establishing their pecking orders. When you physically discipline a cow/steer, you're speaking a language that they understand. You're not being mean, you're teaching them manners. While you will still give many positive interactions (feeding, grooming, watering) there will be some negative ones too (disciplining for bad manners) Usually, the positives will outweigh the negatives and he will learn that all is good when he follows the rules. The only time he get's disciplined is when he breaks them. It's not much different than raising a toddler. Abused animals, ones that are beaten for no provocation, don't get the positives so they are AFRAID of people. They may turn mean or be overwhelmingly fearful of people. You are not abusing him by teaching him manners. You are training him to behave.
Second, you physically cannot push around an animal that outweighs you several times over. So you have to use the sensitive spots on his head. Twist his ear or smack him on the nose if he violates "the rules." You may want to use a riding crop or a stout switch to get his attention while yelling in a big mean voice , "NO!" Eventually he will stop at the verbal cue.
So behavior rules:
1. Create a 4 foot "bubble" around you and all other humans (You are in the center of the bubble). He should not ever invade that space. If he does, smack him on the nose. Now you're thinking, "But he's a pet. Can't I pet him and brush him, etc." YES you can. We have a couple cows that we pet and brush and groom. However, they never approach us, we approach them! Occasionally, one of our more affectionate cows will enter the bubble. However, they always do it very tenatively, since we've trained them that humans are the dominant animal in the herd. If I were to make a startled move or something, they'd immediately back off, and that 's how I want it.
2. Don't feed him out of your hands. That confuses the bovine mind. In a herd, the dominant cow always keeps the best feed for herself. She doesn't share at all. If you are handing over the treats, then you are kind of teaching him that he's dominant over you. Put out the food, keeping some space around you. I stand on one side of the trough, while the animal is on the other side of the trough. Now, some people might take issue with this. Honestly, in our herd there are some cows that we feed from our hands. However, again, they take their treats tenatively, without crowding us. In your shoes, with the over-familiarity that LD has for you, this may be one way for you to re-wire his brain to respect you as the dominant animal.
3. Never allow him to run at you and crowd you. Smack his nose and make him back off.
4. Learn the signs of cattle aggression and dominance. Him running toward you, shaking his head, pushing on you are all ways that cattle show dominance. He may not be playing when he does this stuff.
5. Don't play with him, chase him or let him chase you. I don't like my 16 yo daughter to play wrestle with my 6 yo son. She's much bigger than him and even accidentally could hurt him badly. Playing with a cow/steer not only erodes the natural respect that they have for people, but they don't even have the sense to understand when things are getting out of hand.
6. Don't reinforce his bad habits. If he's used to rubbing up on you for treats or scratches, don't allow him to do so. Remember, YOU are to approach HIM for these things. If he rubs on you, he's violating the bubble and should be smacked for that.
Some people may think these measures harsh. And, for a calf raised on our farm, I seldom have to use these extreme measures. However, your steer has gotten way out of hand and he's going to hurt you or someone else someday. On our farm, from the time an animal is born, they are taught respect of people. It usually only takes a handful of times before they understand the rules.
You need to be 100% consistent with implementing these rules, as does anyone else handling him. And, keep your eyes open. He will probably reform for awhile, and then a few weeks down the road, he will "test the waters" and see if you really meant it. Some animals begin slightly pushing boundaries, while others will do it in a big way all of a sudden. Either way, you have to respond in a big way.
Anyway, that's what I would do if I were dealing with that steer. You can do what you want, but please be careful.