The US dairy industry contributes roughly 1.58 percent of the total US greenhouse gas emissions; however, it also supplies the protein requirements of 169 million people, calcium requirements of 254 million people, and energy requirements of 71.2 million people. A suggested solution to increasing food production worldwide while reducing greenhouse gas emissions has been to eliminate or reduce animal production in favor of plant production. In an article appearing in the Journal of Dairy Science, scientists from Virginia Tech and the US Dairy Forage Research Center studied the effects of dairy product removal on greenhouse gas emissions and nutrient availability in US diets under various removal scenarios.
source https://phys.org/news/2020-10-dairy-cows-essential-nutrient-effect.html