My son has been having problems with his poo since starting cows milk

We’ve had this since cows milk, we tried lots of prune/pear sachets in her food, fruits, lots of water etc but nothing helped so we got lactulose from the pharmacy which has softened it a little bit but don’t want to rely on it.
When we took her for her jabs I asked and was told they don’t actually need cows milk as long as they are getting calcium elsewhere in their diet, suggested moving to oat milk or just cutting it out completely.
Our girl still has a bottle for comfort in the evening and I thought the morning but since we’ve offered cows milk in a beaker in the morning she largely snubs it and doesn’t seem bothered so we’re just reducing the cows milk gently and seeing if that helps her poop. She’s no longer crying when she poops so must be helping!
Not sure if any of that is useful but maybe see what the gp/pharmacy says.

Try swapping to gold top milk its higher in fat but has A2 protein which is easier for them to digest and easier on their little tummies xx

I would speak to your health visitor, that sounds like a lot of milk! If you need to feed that frequently I would trying just giving an ounce or 2 per bottle. Are they drinking plenty or water? I was led to believe milk should be just part of a healthy diet as in a small bottle/cup per day if they’re eating well too x

I’m definitely not an expert but I don’t think a cows milk allergy starts like this. I assume you either gave formula which the majority are made from cows milk or breastfed before this, unless you have a dairy free diet. That does sound like a lot of milk at this age but hard poos also show dehydration so more water might help like said.

My LO has cows milk allergy and it doesn’t manifest this way - it’s more likely to cause runny mucus poos. This sounds like she’s constipated.
I think she might be drinking too much of it - it’s quite heavy but everyone tolerates that volume of milk well. Defo speak to GP or HV but in the meantime I’d try to cut back, maybe you can offer plant milk. Babies this age don’t need that much milk as long as they’re having dairy in their diet x