THE SIGNIFICANCE OF LIVESTOCK AS A CONTRIBUTOR TO GLOBAL GREENHOUSE GAS EMISSIONS TODAY AND IN THE NEAR FUTURE

Abstract

In animal agriculture, the greatest contributors to methane emissions are enteric fermentation and manure man agement. Enteric methane emissions were higher with ruminant animals while manure storage methane was high er with swine and poultry. The main course of agricultural nitrous oxide emissions is from the application of ni trogen fertilizers and animal manures. The most cost-effective way to reduce CH4 production is to improve feed efficiency. In low-intensity systems, CH4 production per unit product can be markedly reduced by improving feed quality and feeding intensity. Inhibition of methanogens, involvement of other H2 alternative sinks e.g. inclusion of dietary fat, can result in a reasonable reduction in CH4 production. Generally, some feed additives such as con densed tannins (CTs), fibrolytic enzymes and other factors e.g. methane inhibitors, vaccines, defaunating agents etc, have the potential to mitigate CH4 production from ruminants. However, there are also some disadvantages, e.g. they are costly and not economical to apply at the farm level, and many have only short-term effects on CH4 production thereby diluting the maintenance costs. The range of global mitigation potential to improve carbon sequestration and other factors are documented. Global and Sri Lankan scenarios on emissions and emission in tensities from dairy production and the mitigating options are discussed. It is highlighted that removing animal agriculture is not a good solution to reduce greenhouse gas emissions. It is also suggested that combining produc tivity increases in crop and livestock sectors appears to be the most efficient way to exploit mitigation and food security co-benefits.