When and where possible it would be at a benefit to your health to avoid dairy or high lactose containing products.
Lactose is a simple sugar found in cow's milk. It is a simple sugar that can be very hard for a human gut to digest at times. Don't be fooled this simple sugar is meant for a calf (baby cow) and not for human's so I'm sure you can understand why so many people are having gastrointestinal issues with it. The common term for these gut problems is usually referred to as ‘lactose intolerance’.
And believe it or not the main reason this discomfort occurs is more because of the way we process our modern day cow’s milk than the raw milk alone. Due to health regulations and government laws, farmers have been told to pasteurise and homogenise the milk so that it kills the so called bad bacteria and makes the milk smoother to drink.
You will usually find lactose in all diary products made from cow's milk so be aware and check the back label when you buy these food products.
As a great alternative, if you can find raw milk, mostly sold at farmers markets you will usually find none of the lactose intolerance symptoms occur due to the milk not being processed in anyway. But also remember you can always opt for many other milk alternatives e.g. hemp, coconut, cashew milk.