Reduction potentials for methane emissions from ruminants

The reduction of greenhouse gases is an issue of worldwide importance. Starting out from this fact, the paper aims to describe the processes determining methane production (CH4) in the keeping of farm animals. The CH4 emissions are calculated for different forms of the production of ruminants for edible protein of animal origin. Milk protein can be produced with considerably fewer methane emissions than the meat protein of cattle. At the same time, it can be shown that the methane emissions are generally higher at a higher production level of the ruminants, but decrease per unit of produced product. With increasing production levels, these effects decrease continuously. Under consideration of the calculated methane emissions, the increase of the animal performance and a possible reduction of the number of ruminants should currently be the most effective measure for obtaining a decrease of methane emissions at short notice. Animal health, lower animal losses, long periods of productive life of cows and short growing period of heifers are further possibilities to reduce the methane emissions by ruminants. Continuing research is necessary to achieve practicable and reproducible results with other reduction possibilities. Further examinations are intended to investigate the complex interactions between the animal food production and the saving of resources (ground, water, fuel, fertilizer effort, transportation expense, etc.) with regard to energy use and ecological damage (CH4, CO2, N2O etc.) to the whole food chain in greater detail. Reductions of environmental emissions are required to take action regionally, and thus inevitably on the level of the individual farm; but the simultaneous globalization of food production requires worldwide activities.