From a recent interview with food sustainability expert Dr. Jude Capper:
What is the environmental impact of beef grown on grass compared to conventional beef?
Dr. Capper – "Cows grow more slowly when grass is all they eat. If all of the beef in the U.S. were grass-fed we would need an additional 64.6 million cows in order to match the amount of beef produced in 2010. That would require an additional 131 million acres of land, which is about 75% of the state of Texas. That many cows would need an additional 1,700-billion liters of water, which amounts to the annual consumption of 46.3-million U.S. households. These cows would generate an additional 135 million tons of carbon which would be like adding 26.6 million cars to the road every year. So, in terms of land, energy, water, and carbon, grass-fed beef has a much larger environmental impact than conventional beef production."
Is it more natural for a cow to eat grass instead of corn?
Dr. Capper – "Cows probably did not eat corn 500 years ago. But does it matter if it's natural as long as it improves environmental impact, food safety, and beef affordability? Almost nothing we do today is 'natural' compared to 500 years ago. We have cars and airplanes. We have treatments for cancer and heart disease. Why is it that in every other business sector we celebrate increased efficiency and productivity thanks to new technology while when it comes to food some want it done the old-fashioned way?"
Read the entire interview: