No other species on the planet drinks the milk of another species, let alone after weaning. Cow's milk is for baby cows. It is completely unnecessary for humans and increases the risk of chronic decease including breast cancer and prostate cancer. Like all other mammals, the only milk that humans need to drink is their mother's, until weaning. 65% of people worldwide are lactose intolerant after weaning, and in some countries it's as high as 90%.
And milk production is extremely cruel. Cows do not naturally lactate constantly. Like all mammals, they need to be pregnant or have young offspring to produce milk. So to keep them lactating, farmers keep them constantly pregnant by intrusive artificial insemination. After a 9 month pregnancy, their baby is taken away within days of birth, so that they don't drink their mother's milk. The bond between a mother and her calf is strong, and the separation is painful for both.
This 5 minute video by Erin Janus quickly explains dairy and common industry practices. WARNING: GRAPHIC CONTENT.
As male calves will never produce milk, many are destroyed and discarded within days, as waste products of the milk industry, whilst others are slaughtered for veal. Female calves are usually raised on milk replacer and then impregnated at 15 months. After 5 or 6 pregnancies they are exhausted and start to produce less milk, becoming less profitable for the farmer. They are sent to slaughter for their meat at age 6 or 7. The natural life span of a dairy cow is 25 to 30 years.
Their death is painful and commonly involves stunning by pneumatic bolt and being hung upside down by one leg. Often while still conscious, they have their throat cut open by a knife and are left to struggle as they bleed out.
Considering that dairy products are not required for human health, and increase the risk of chronic disease, this cruelty is completely unnecessary. If we purchase dairy products, we finance unnecessary animal cruelty.
There are many alternatives to dairy milk, including soy, almond, coconut, rice, oat and flax milk, many of which contain the same amount of calcium as dairy milk. There are also many available varieties of non-dairy chocolate, cheese, yoghurt and ice cream.
This 3 minute video by Animals Australia explains the life of a male calf in the dairy industry. WARNING: GRAPHIC CONTENT.