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GREENHOUSE GASES: Livestock and livestock waste produce gases. Some are local, such as ammonia, whereas others, such as carhop-dioxide, methane and nitrous oxides, affect the world's atmosphere by contributing to global warming. Livestock's contribution to that effect can he estimated at between 5 and 10 percent.
Biogas in China
In China more than 5.3 million rural biogas systems are in place, producing 1.25 million m3 annually. Biogas is used for household heating and cooking, poultry hatching, tea drying, grain and fruit storage. The slurry is used for fertilizer, fish farming and for feeding pigs which show good result in the semi-intensive production system.
Limiting the emission of greenhouse gases, particularly nitrous oxides and methane, is a major concern hut technical solutions arc available. For example, methane can be recovered from lagoons and used directly as fuel or to generate electricity. The trend to intensive production of pigs and poultry has changed the ratio of monogastrics to ruminants. This has helped to keen livestock emissions of greenhouse gases steady because, unlike ruminants, pigs and poultry do not emit significant amounts of methane as part of the digestion as ruminants do. Virtually all efforts that improve animal productivity will reduce methane emissions.
Thus, livestock emissions are stagnating despite a strong overall increase in production. The challenge will be to ensure that the rapid expansion of intensive production in developing countries does not result in damaging pollution. As the West has found to its cost, once present this is very difficult to deal with.
Methane can be recovered and used directly as fuel or to generate electricity. 1
Methane can be recovered and used directly as fuel or to generate electricity. 2
FEED PRODUCTION: Production of animal feed affects land use through deforestation and change of habitats. There are also direct effects of cropping on soils, water and air, and indirect effects as a result of the production and use of inputs and machinery. More important, however, is the fact that feed production areas are not directly linked with livestock feed use, leading to a transfer of nutrients from feed producing areas to areas of high livestock concentration. The result is infertile soil in farmers' fields and pollution problems for livestock producers.
DOMESTIC ANIMAL DIVERSITY: Industrial livestock production uses a very limited range of animal breeds and this has led to the extinction of some local livestock breeds and the genetic erosion of others. These local breeds sometimes have a specific genetically determined capacity to cope with the climatic, nutritional and disease challenges in a given environment. These traits may be lost for future generations. There are currently 600 breeds at risk of extinction, representing about 20 percent of the total global livestock breeds. The trend of breed erosion has been fostered by development policies favouring exotic breed (subsidized imports and multiplication of exotic genetic material) and technologies (subsidized mechanization, replacing traditional draught animals).
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