The Onion

Statistically, that cow had a short and miserable life in a factory farm before being killed at a small fraction of their potential lifespan. They were fed a grain-based diet that caused far more mice deaths than it would have to use the land to grow crops to feed humans directly.

Even in the situation you've presented, which again is an exceedingly small percentage (<10% globally, <1% in the US), land is being used which could be rewilded to promote biodiversity. The cow in question is still contributing to GHG emissions and will again be killed around 16 months of age.