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[–]jet199 2 insightful - 1 fun2 insightful - 0 fun3 insightful - 1 fun -  (0 children)

OK, so producing the enzyme to digest lactose isn't the only way to deal with it.

Many people have gut bacteria which produce enzymes to digest it for them, which is why some people with lactose intolerance can get some tolerance if they introduce it slowly. The other obvious way is to process the milk into things like yogurt or cheese where the bacteria digest the sugar.

Also the majority of children can digest lactose so cows milk would still be useful in weaning kids early, which is the main use of it outside of Europe. Breastfeeding has a slight contraceptive effect so by stopping women breastfeeding you can have them popping out one kid a year until they die, which then creates loads of free labour for your farm.

Lactose tolerance must have evolved relatively slowly because its spread isn't even complete. Scandinavian counties which are highly dairy focused still have up to 5% lactose intolerance which is a lot of people who have trouble digesting what would have been the main protein source for most of their history. The UK, again massively dairy focused, is even higher at 15% and they didn't even have yogurt until the 1970s. That's a lot of sick people who've had to put up with milk since the bronze age.