Dairy intolerance?

So how do I know if ds has any sort of dairy intolerance? Over the last 6 weeks or so I have been trying to see if the organic Jalna blueberry yoghurt is making ds spew and after this afternoon I'd say I'm 100% sure that it is. He has loads of regular cheese and loves it, I give him cheese every day, sometimes twice a day in the form of regular cheese such as mature or tasty and often cottage cheese and he has no worries with them. I have also added full fat cream and a dash of milk to some foods and that has been no worries either so why is the yoghurt making him sick? Are there hidden sugars in that yoghurt or preservatives? He also has goats milk yoghurt everyday and that is not a problem either. His diet is really good with the only processed foods being the yoghurts and cheeses, everything else is make from scratch with fresh fruits, veg and organic grains and proteins, maybe his belly can't handle something in the yoghurt? Is this type of thing common, I really don't wish for him to have an intolerance to dairy. Guess I'm not really being clear on what answers I would like from this thread, maybe just some light on the subject and others experiences with dairy. TIA

It doesn't sound like a dairy intolerance if he can take cheese, cream and milk. My DS2 had a suspected dairy intolerance as he would also get a rash around his mouth and vomit. He did grow out of it.
Perhaps it's just too rich, maybe try a plain yoghurt. I know they say that babies yoghurt are a gimmick, I tried my kids on these first before regular yoghurts. Could be worth a try.
If he is happy enough to have goats milk yoghurt you could just hold off on other yoghurts until he is a bit older and try again.

Its not going to be a dairy intolerance if he is having cheese, milk and cream, it could be the bacteria in the yoghurt or the fruit. Maybe try a plain yoghurt instead?

There are two different types of dairy intolerance, but neither of them seem to fit here:
1) intolerance to milk protein - but if he had this he would have huge problems with cheese
2) intolerance to lactose (which is rare in babies) - but if he had this he would have problems with breastmilk

It may be the acidity of the yoghurt; it's also better for babies to have full fat yoghurt than any kind of lower fat variety. I wouldn't worry about it - just steer clear of that type of yoghurt for a month or so.

Ds1 had problems with full fat adult yoghurt but was fine with kids yoghurt and lite adult yoghurt. Apparently full fat yoghurt can be a little full on for their tummies. He did eventually grow out of it and could have normal adults yoghurt. Maybe try a low fat one or give the kids yoghurts a go.