Cows milk - vile stinky nappies!

[MrsBonkers]

I'm just trying to get my 13month DD onto cows milk. We've been using it in cooking and on her cereals since we started weaning at 6 months.
I've been giving her cow's milk in her daytime bottles (little madam still wakes for food a couple of times a night - which I give toddler milk.)
Her nappies have been bright yellow and stinky!
Is this normal when making the change from formula, or do I need to ease her into the cows milk more gently?

I did a gradual switch over one feed at a time and gave a few days between swapping each one to make sure they were ok with it

Thanks.
Of course it could be that she is teething again or that she had her jabs just over a week ago.
I might try half and half toddler and cows milk.