Vegans do not consume the milk of other species for reasons mostly related to animal rights and environmental concerns, namely climate change, ocean dead zones, and deforestation. They may object to features of dairy farming including the necessity of keeping dairy cows pregnant, the killing of almost all the male offspring of dairy cows (either by disposal soon after birth, for veal production, or for beef), the routine separation of mother and calf soon after birth, other perceived inhumane treatment of dairy cattle, and culling of cows after their productive lives.