This is an email i received from an mner about this.
"I did give my ds a bottle of ebm from early on - for the first few days after he was born he was really sleepy and seemed to have no appetite. I tried putting him to the breast for the first 36 hours but he just wasn't interested. By that point the midwives were getting twitchy because he hadn't fed at all, so we offered a cup of ebm. He took this ok but I ended up tipping most of it down his front, so I decided to offer him a bottle when he wouldn't take the breast. He took to the bottle very easily - it was a bog standard Avent newborn teat.
I was having to wake him every 3-4 hours to encourage him to feed - he just slept otherwise - and I always offered the breast first. By about day 3 he would take a short breast feed but was really hard to keep awake and he'd drop off after a couple of minutes, so I gave him ebm top ups after most feeds.
By the time he was about 10 days old, he was taking a full feed from the breast and I didn't have to bother with top ups.
All this was very much trial and error, though. There was no grand plan! I hadn't discovered Mumsnet in those days and just did what seemed right.
I wanted to keep him familiar with the bottle though, so he had a bottle of ebm every night at about 10.30 pm, with DH, so I could go to bed early.
He was fully breast fed until 5 months, when I started winding down in preparation for returning to work. It was only for that reason, not because he wouldn't feed, or I didn't have enough milk. If I hadn't been going back to work I'm sure he'd have carried on much longer.
He never seemed to favour the bottle over the breast or vice versa, and I never had a problem with my milk supply.
I think the reason that it worked for us was that I pumped from day 2, so my milk supply was stimulated when ds had no appetite to stimulate it himself. Also, I always put him to the breast first, before the bottle. He was so sleepy at birth and ended up with low blood sugar levels due to not feeding enough, and this made him sleepier - it was a vicious circle that we needed to break by getting milk into him another way. In this instance, the oft-quoted advice of putting him to the breast frequently wasn't enough.
I found it a lifesaver too - being able to leave him with DH or a granny and have a bit of time off and not have to worry about him taking a bottle - it was fab being able to do either.
I hope that helps - good luck with your lo :-)"