Methods for Animal Production Systems

Chapter 4: Quantifying Greenhouse Gas Sources and Sinks for Animal Production Systems

Animal production systems include agricultural practices that involve breeding and raising animals for meat, eggs, milk, and other animal products such as leather, wool, fur, and industrial products like glue or oils. Animals considered in this sector include cattle, swine, and poultry, along with other animals such as sheep, goats, American bison, llamas, alpacas, deer, horses, mules and asses, rabbits, and fur-bearing animals.

This chapter provides methodologies and guidance for reporting greenhouse gas (GHG) emissions associated with entity-level fluxes from animal production systems. It summarizes animal management practices and their associated GHG emissions, then describes the methods for estimating GHG emissions from enteric fermentation, housing, and manure management.

Enteric fermentation:

• Dairy cattle
• Beef cattle
• Sheep
• Swine
• Other animals

Housing:

• Methane (CH₄) and nitrous oxide (N₂O) dairy production systems
• CH₄ and N₂O beef production systems
• CH₄ and N₂O swine production systems
• CH₄ and N₂O poultry production systems
• CH₄ and N₂O other animal production systems

Manure management:

• CH₄ and N₂O for solid manure storage (stacked)
• CH₄ and N₂O for composting
• CH₄ and N₂O for aerobic lagoons
• CH₄ and N₂O for anaerobic lagoons
• CH₄ anaerobic digesters

The magnitude of GHG emissions from animal management depends primarily on the quality of the diet, the animals' physiological status and nutrient requirements (e.g., grazing, pregnant, lactating, doing work), feed intake, and the systems in place to house animals and manage manure.