Climate Change - Beef

Knowledge Nuggets

• Methane gas belched from the mouth contains about 10% of feed metabolisable energy. Methane losses of 200-500 g/day occur in adult beef and dairy cattle. Methane comes from hydrogen produced by rumen bacteria that digest fiber.

• Nitrous oxide is a potent greenhouse gas that has 13 times as much global warming potential as methane (on a weight basis) and comes from urine, feces and nitrogen fertilizer especially from waterlogged soils.

• Carbon dioxide is not normally included in calculations of emissions from agriculture because production is normally balanced by plant uptake. However, land use changes effect carbon emissions. For example cultivating grazing lands increases emissions as soil carbon is lost or converting grazing lands to forests lower emissions as carbon is sequestered in trees.

• Green House Gas (GHG) emissions associated with animal maintenance will be a smaller component of emissions per unit of production in high producing animals than low producing animals.

• Select animals with a high net feed conversion efficiency.

• Select lower methane producing animals (typically 60-80% of "average" producers) and cull high producers (120-130% of average) which also improves feed conversion efficiency.

• Feed good quality diets as less methane is produced from each kg (DM) from legumes than grasses. Production is also increased by using legumes so maintenance costs are lowered/unit of animal production.

• Good animal management will lower methane by maximizing production from feed that is eaten. For example a dead calf represents zero animal production from a cow producing methane for one year.

• Feed a slow release ionophore especially with grain feeding to increase feed conversion efficiency.

• High grain diets lower methane production per unit of feed eaten and per unit of product produced. However grain production has a very high GHG cost from soil carbon losses, carbon emissions from fuel consumption, drying, fertilizer, tractor manufacture and transport. Methane can be lowered at the expense of other greenhouse gases.

• Balance rations to minimize excess production of urinary urea and total nitrogen in manure. Nitrogen in urine and feces is responsible for the majority of nitrous oxide release from pastures.

• Take care of effluent. Either incorporate it back into the land or capture methane from storage facilities for heating or electricity generation.