My job is to raise calves & I often have trouble with Belgian Blue calves. I've found that bonding them real good to you works better than anything to get them to drink. If they think you are mom, they will want to drink from you. Rubbing their foreheads, simulates a mothers lick & it works on most newborns that spit the bottle cause they want their mommas. Teasing them is also one of the best ways to get them to drink. I offer a bottle & then take it away if they try to drink & I feed a baby next to them. I put milk on my fingers, put it in the mouth & take it out immediately. I use instinct & anything/everything so it's hard for me to explain without actually being there & trying different things. One thing I've found is with many calves, trying to force them by holding the bottle in their mouths just makes them spit it out.
I'm like: Do you want this bottle? Nope sorry, you can't have it. Sure you want it? Nope, not gonna happen!
Also, if you can tie/crush any of your cows, heifers,other bigger calves... tie them, bring the baby & put the bottle by the udder so he sucks on it & stand on the same side as him. Then you just tilt the back of the bottle away from the cow so you are now feeding him next to the cow.