As a child I suffered with asthma, and on a nutritionist's advice I stayed away from dairy products for a couple of years. It made massive difference to my breathing, and allowed me to cut down on the inhalers and chemicals I was putting into my body. Though I grew up in the hippy-organic-food-mecca that is West Cork, the options for non-dairy milk were far more limited than they are now. Thankfully, overpriced and oversweet rice milk has given way to gorgeous almond and soya milks which you can get in pretty much any supermarket.
coffee with foamed almond milk
These days I stay away from cow's milk for another reason. Think back to your secondary school science or home economics classes; anything ending in -ose is a sugar, and sugar is a carbohydrate. Cow, goat and sheep milks (even low-fat) all contain lactose.
You can think of your traditional cow's milk as what's left over once all the good stuff has been skimmed off, and you can get more than enough calcium and other good nutrients from cream and cheese, both of which contain far lower levels of carbohydrates.
A cup of full-fat milk will have about 12g of carbohydrates in it, while a cup of double cream will have about 6g. If you're trying to stick to a low-carb diet (less than 20g per day) then even adding milk to your tea or coffee can push you close to your daily limit.
S and I are both into our coffee, and thankfully both almond and soya milk foam beautifully. If you feel like it's still missing something, try mixing a little bit of double cream with water and you really won't know the difference.
There are so many other milk options out there that going without cow's milk is really no challenge at all these days.