I would be very interested to know how you get on with this and indeed if this service is still provided.
I dont know if P&O still do this (as its 12 years since I took a baby on a cruise) but back then they had a special services division and I was able to pre order all my baby food/juices/milk etc. at no extra cost before we sailed. It was all ordered for me (back then it was anything that could be purchased from boots -so its was boots own brand or anything else they generally stock) I was then provided with a cupboard in the main ding room and I could go and help myself to whatever I needed or could take what I needed back to the cabin. As I say times have changed - you would have to phone to see if they still provide this service. I havent been on Ventura but assuming it has a night nursery same as Oriana, provided you can get baby settled you can leave baby in the night nursery and go off and enjoy the evening. You can also pay for one of the trained staff to give personal incabin baby sitting. They used to have a limited amount of sterilisers and baby equiment on board which you got from the childrens playroom. As you have booked already I assume you requested a cot at time of booking??? Would make sure you take enough nappies though as although they may have a limited stock they probably wont be your preffered brand/type/size. In the daytime you can go into the playroom with baby but you will not be able to leave baby, you have to stay to play. Hope this helps, like I said it was a long time ago and you will have to get onto P&O to check this out for yourself.
I don't wish to sound harsh but it wouldn't it have been a good idea to find out before you booked? If you are boarding at Southampton, you will be able to take enough food and nappies with you if P&O don't have the pre order system as mentioned by Bradbury. It will be a logistical problem but we managed it when ours were babies. Most cruise ships offer babysitting services and we used to hire our cabin steward to sit in the cabin every night for the first few years. Our children rarely woke up but if they did, they would recognise the sitter. I always took loads of sterilizing tablets with me as you can use anything as a receptacle when you want to sterilize things. Good luck and remember, infants are hardy little angels.
I hope it works out well for you, but you really should have checked this out first.
On our recent cruise (on Celebrity's Galaxy) around the Eastern Med the couple next door to us had a small baby and when we saw them arrive our hearts sank - visions of being kept awake at night by the sound of wailing through the cabin wall! I have to say that this didn't transpire at all and we heard not a peep.
We did our first cruise on Oceana last Autumn with our little boy, who was then 10 months - and we had a ball. The facilities are excellent. There were plenty of nappies and baby food on board, we were given a travel cot for our cabin, the nursery and its staff were outstanding (wife is a teacher who has done loads of childcare as well, and she rated it all outstanding).
Do take your own supply of nappies on board, as its not quite as if they hand whole packs out for free, though - for us, if we wanted to change him in the day, we'd pop along to the nursery and make use of nappies and stuff there.
There is also an excellent Night Nursery which will take very good care of your little one every night from 6pm to 2am, if you want!
Sorry, forgot to add that, of course, Oceana is part of the P&O fleet with Ventura. Its reasonable to expect that the service on Ventura is identical, in fact we were told this as much by the staff on Oceana. We had such a good time that we've booked to go on another cruise this summer, largely because of the excellent childcare (we're going on Cunard, we would have gone for P&O again but we saw a great offer, it also helps that Cunard's kids facilities appear to be as good as P&O).