Also, milk just tastes different depending on the cows, and how they’re raised and fed. Most likely what you’re noticing there is the difference between grass-fed and corn-fed. Cows aren’t naturally adapted to eat corn; they grow better and healthier on grass, which is how they’re raised in the UK. Corn-feeding is a primarily North American practice because corn can be sold at below the cost of production in the US thanks to government subsidies in place since the Great Depression.