PETA and other animal liberationists don’t believe there should be any cows. Cows are domesticated animals. Domesticated animals, by definition, suffer at the hands of man. The answer to the environmental damage caused by cows is the same as ending the human tyranny over animals: Humans should cease immediately from making any use of domesticated animals and either allow those alive today to live out their lives in peace without their procreating, or put them down if that would not sufficiently alleviate their suffering.
Then, within one generation, the problem would be over.