Yes it was pre 2004 when all the Mad Cow Disease recommendations came in. Not that long ago really.
Now it is illegal to feed cows, blood, composted wastes from chicken coops, including feathers, spilled feed and feces, but you can still feed rendered matter from cows to pigs and chickens, and rendered pigs and chickens can be fed back to cows. So practices that involve using animal remains to make cattle feed are still allowed.
And because farmers aren't allowed to feed the cows blood and direct animal products anymore they feed them extracted and solvent Soya proteins in various forms, which can unbalance hormones, and ionophores, including monensin - an antibiotic, which though it increases milk production, changes the proportions of constituents of the milk.
Organic milk comes from cows fed organic vegetarian food, which does not contain chemicals such as monensin.
Our family does well on organic dairy products and meat also - perhaps organic might be a better milk for you to drink also OP.
Organic production is definitely better for the environment - water courses etc - to have organic swards with are naturally fertilised.
You can increase the productivity of a sward -by mixed grazing cattle and sheep together- by about 10% - without having to dump chemical fert on the land, and into runoff.
Time for change?