In many situations it is often a case of 'six of one, half a dozen of the other' though. We only have the OPs side and she has listed 1 thing that her MIL has done which is questioning her parenting, once not listened to her instructions. That's all quite normal in the first few months of having a child, she is learning her new role as a grandmother and was most likely asking out of concern for her GC. In fact many new parents face far more interference from GPs. Possibly the only thing she has done wrong is referring to the OP as a cow, which yes she should stop if OP has asked her to (I don't think she has said if she has?) and may have been meant as a joke. So for all we know, and IMO, it sounds like the OP is making a mountain out of a molehill as she doesn't like her MIL. The guilt trips and unwanted medical advice can surely just be brushed off?
Normally I would say that in these sort of situations it's best to humour the new mother as she will likely mellow out with time. However, I feel like the OP is being unreasonable. She expects her MIL to change to suit her, without questioning whether she shoulders any responsibility or blame. It seems like the OP wants everyone to agree with her and do exactly as she says, including her husband who should be able to take his child to see his mother without needing the OPs presence or permission.