Air Quality, Greenhouse Gases, and Dairy

What is the origin of GHG on dairy operations?

Carbon dioxide (CO2) is emitted from a number of natural- and mechanical processes:

  • Respiration of all living organisms – in the soil, plants and animals

  • Combustion of gasoline, diesel, and other fossil fuels used to power farm machinery

  • Microorganisms in manure


Methane (CH4) is emitted from:

  • Enteric fermentation in ruminants which occurs as feed is digested

  • Microorganisms in manure

  • Manure deposited in grazing pastures


Nitrous oxide (N2O) is emitted from:

  • Nitrification and denitrification processes that occur during crop growth and in soil

  • Barn floor, especially in bedded pack systems

  • Crust formed on top of stored manure

How can a dairy reduce its carbon footprint?

The carbon footprint of a farm is the net sum of all GHG emitted in CO2 equivalents. Strategies to reduce a farm’s carbon footprint are:

  • Increase production per animal

  • Feed more grain and less forage

  • Haul manure off-site daily, eliminating storage

  • Cover the manure storage facilities and flare the CH4 to convert it to CO2

  • Install an aerobic digester to create biogas and electricity to reduce the reliance on fossil fuels

  • Practice reduced tillage and convert cropland to perennial grasslands to sequester carbon.

Contact Information

Alexander Nikolov Hristov
  • Professor of Dairy Nutrition
Phone: 814-863-3669