We artificially inseminate the female, repeatedly and forcefully, often with an instrument called the “rape rack” or otherwise a mans bare hand shoved inside her
This is done because - like female humans - female cows only produce milk (lactation) when they are pregnant, as it is food for their baby. We force them to be pregnant, carry a child, give birth and then snatch it away immediately because we make a profit from exploiting their bodies.
The newborn babies, if female, suffer the same fate as their mother. If male, they are sent to be killed and eaten. That breastmilk, designed to grow a calf as large and as rapidly as possible, is stolen and bottled to be sold.
All because we have brainwashed our society into thinking baby cow growth fluid is designed for human consumption and we are too lazy or stubborn to reach two inches over and pick soy/almond/oat/coconut/hazelnut/hemp milk instead.