Well Weston is 19 months (or will be on Jan 3rd) and I still give him MOSTLY formula. I will offer him cows milk once or so a week as in maybe a 4 or 5 ounce sippy cup/bottle with a meal. (I offer him juice/water/formula for more often)
On occasion he'll ask for milk (signing) it's rare, but when he does, I'll give him a 4 ounce cup or bottle. For a while there I was letting him have a special treat of 'ovaltine' (about 4 ounces) in the afternoons and he loved that.
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Well let's see...I would say VERY SLOW...my transistion wasn't really a process of one part this and one part that for one week, etc...it was more a offer a little here and see what happens, offer a little more later down the road and observe. And I didn't notice his tummy adjusting until closer to 18 months really.
He still is not on FULL cows milk, only because I prefer formula. It travels well...I can put a can in the car and a bottle of water and not worry about it spoiling, etc. Milk would have to be cold, etc...
Some mothers feel that your child should jump straight to cows milk at 1 year of age, but I did some research and reading of my own when Weston turned 1..and honestly cows milk isn't all that great from what I found. I love MILK (myself!) don't get me wrong...but on the children's immature digestive system it is fairly harsh, compared to other options. Some of the readings I had read, suggested saving cows milk until age 2 (one even pushed for age 3). And others flat out said Goats milk is a thousand times better then cows milk for humans. (said that it's more like breast milk then cows milk and easier on the digestive system)
I feel Weston is getting plenty of his dietary needs from various foods...and for me to have formula or powdered goats milk (which by the way tastes just like cows milk if it's really cold...warm it's GROSS IMHO) is just as easy as buying a gallon of milk.
I talked with two of Weston's doctors on two different occasions and they both agreed that cows milk is not required for their dietary needs, and that formula is totally fine to offer for however long I feel I want to offer it. I asked about goats milk instead, and they both agreed that goats milk was a fine sub for cows milk.
So if you aren't in a rush to push the cows milk...then I'd wait a while...and just offer a variety of liquid options (if he's already good with his formula, maybe try the formula that is for older children...I think it has less calories...I give both...Weston's not picky on his formula) But try small amounts (maybe 2 ounces at a time) of goats milk, some soy milk, cows milk, juice, formula, etc...just to get him used to various flavors and I'm sure he'll have a preferrence and if not, great, we could all use some variety in our diets.
Strict rules on cows milk is silly (IMHO) I LOVE cows milk, but that doesn't mean I'll die if I don't get it for a day, week, or month...ya'know what I mean...Let his little system mature and all those foods will come to...but if you push them you can actually help develop an allergy.
Weston was very sensitive to various foods that gave him gas and made his nights miserable...so I backed off and stuck with pretty mellow foods I knew were AOK for long periods of time between the 6 month & 18 month markers...I actually had him on the B.R.A.T. diet for a while (a few different times), just to get his system back to a nice basic start. (are you familiar with that diet? Bananas, Rice, Apples, Toast) so you stick to bread, apple, banana & rice food choices...all fairly blan and safe on their tummies...good to do after a vomit/poopy virus too.
Sorry to ramble on...Just new memories keep popping into my head...lol
In a nutshell...stick to what works and let his little system mature...he's got his whole life to discover cows milk...what's another year or two