Unsurprisingly, this pressure to expand has created a number of environmental and welfare problems, which even the industry itself admits are becoming critical. In the high-yielding breeds used to produce milk today, a cow produces more than ten times the milk she would need to feed her calf. The push to create higher and higher yielding breeds is leading to an increase in disease and illness amongst cows that simply cannot cope. The lifespan of a dairy cow is now often less than three lactations.
via The Ecologist.