Leading organisations working on environmental protection, food security and climate change have realised the role of livestock in GHG emission. There are two major types of GHG emission through livestock animals. Direct GHG emission is the portion evolved directly through animal body by enteric fermentation in ruminants and urine discharge. Moreover, the decomposition of manure is also part of it. Indirect GHG emission involves the emission through fertilizer application and production
AGRICULTURE IS ever augmenting sector globally and biggest contributor towards the insurance of food security. Livestock is an important pillar of agriculture and contributing significantly through milk and meat production. With the advancement in technology and science the methods of rearing livestock animals have also changed. Global food requirements have increased by manifolds and thus the crop production as well as livestock production has to be increased. One of the major shifts is in livestock farming pattern. Previously, it was a common practice to rear animals at farm lands by the regular farmer but now it has become a booming industry with a huge materialistic infrastructure and mechanical advancement. Technology has provided the opportunity to domesticate and rear large number of animals at a place with lesser manpower as machines are at service. For the last few decades the trend of dairy farming has flourished tremendously.
Livestock industry is among the major agro-based industries worldwide. It offers a wholesome amount of food to fill large number of mouths on the globe. Where there are so many benefits, few problems are also associated with this sector. One of the most aching and terrible issue is the negative impact of livestock industry on climate. Everything affects its environment, on the same note dynamic production process of milk and meat is influencing the ecological scales. Mechanized farming has put us into a situation where the alternative sources are not available and current situation is no more acceptable as far as sustainability and eco-protection is concerned. Ever changing rather ever worsening climate is being directly affected through Green House Gases (GHGs). It is a very common term and attributed to all those dangerous gases which can harm life as well as the protective shield of ozone above the earth. In early 20th century the biggest source of GHGs was fuel burning and then it was assisted by our further improvement i.e. mechanical advancement (refrigerators, air conditioners etc) and then our production hubs (humid farming systems e.g. flooded rice production and other is livestock sector). In crux, animal production is a source of GHG emission and this statement is justified through huge literature.
Leading organizations working on environmental protection, food security and climate change like Environmental Protection Agency (EPA), Intergovernmental Panel on Climate Change (IPCC) and Food and Agriculture Organization (FAO) have realized the role of livestock in GHG emission. They have evaluated its potential, estimated the current contribution and future hazards. On an average, different sources declare livestock GHG emission 7-18 per cent of man-caused (anthropogenic) emission. Major share is of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), Sulfur dioxide (SO2) and many other non CO2 gases. There are two major types of GHG emission through livestock animals. Direct GHG emission is the portion evolved directly through animal body through enteric fermentation in ruminants and urine discharge. Moreover, the decomposition of manure is also part of it. Indirect GHG emission involves the emission through fertilizer application and production; feed crops direct CO2 emission, manure application and refrigerated transport of milk. Emission of GHGs from animals is actually associated with different regimes.
Food security in coming years will heavily depend upon livestock sector and the current situation involving the GHG emission is a big threat to sustainability of this dynamic sector. Ruminants hold 80 per cent of land under livestock and use 35-40 per cent arable crops as feed. It puts this sector in competition with crop production and energy synthesizing sectors. Future food and energy requirements must be fulfilled by this sector, it must for sure. There is a difference in developing and developed nations regarding livestock production and thus GHG emission. In developing nations the production systems are not much efficient and the wastage, poor processing and conventional energy consuming processes add a huge amount of GHGs. On the other side, over exploitation of natural resources and intense use of energy systems contribute significantly to GHGs emission.
Importance of livestock sector is very clear and it is inevitable to produce milk and meat through so-called factory farming in present situation. So we cannot control the climatic hazards by simply stopping the process but certain innovations can help in this regard. Solution of this problem lies inside itself. As the sustainable production and safety measures can aggrandize the stability of system and thus erase the potential hazards. GHGs emission can be controlled through judicious use of multiple technologies in a mannered way.
According to FAO, mitigation strategies can be optimized and applied on the basis of characteristics of production system, geographical conditions, ecological situations and technology level. However, few generalized but major categories of mitigation strategies are mentioned below:
Enteric CH4 mitigation
Mitigation through manure management
Optimization of husbandry practices
ENTERIC CH4 MITIGATION STRATEGIES:
It is a very important strategy as it deals with the major stakeholder i.e. ruminants. Enteric fermentation is a big source of CH4 emission which is 4 times more hazardous as compared to CO2. The respiration is very necessary metabolic process generating heat and energy for body functioning. However, increasing the digestibility and assimilation can significantly reduce the GHG emission from animal. Use of more digestible feed is a good option. For instance, using grass meals in place of corn meal can increase efficient digestion and reduce CH4 production in vivo. A large number of studies have supported this idea. Nitrates in low protein diets also offer good control over GHGs emission. Key options or issues covered in this regime are:
l Supplement feeding (inhibitors, exogenous enzymes, electron receptors, ionophores, plant bioactive compounds, dietary lipids and direct fed microbals).
l Feeding management (Feed intake accountability, dose and concentration specificity, quality analysis, proper efficient processing, mixing of rations in correct proportions, feeding frequency and precise feeding technique).
Animal manure production is directly associated with diet type, amount and form. Feces and urine toxicity depends upon feed composition. Manure storage is not a good prospect but inevitable sometimes. Pasture farming promotes the digestibility and the CH4 emission is far less from urine of such animals. Moreover it increases the degradation of N2O substantially. Dietary plan meeting basic requirement and feeding optimal levels of proteins especially to lactating ruminants increase the assimilation efficiency and reduce the ammonical loss of protein nitrogen. Reduction in total dietary protein and addition of amino acids as supplementing material is a good strategy to decrease GHGs. Following components can be adopted as management strategies:
l Manure storage
l Waste management and disposal
l Manure processing
l Anaerobic digestion and nitrification inhibition
l Cover cropping
l Chemical treatments of manures
l Safe application
IMPROVED ANIMAL HUSBANDRY:
Improvement in living standards, hygienic parameters, feeding habits and overall animal health can ensure the efficiency of feed and inputs. It will certainly lower the losses through emission of noxious gases. However, recommendations and practices must be site specific and quite in line with the domestic conditions. Following components must be kept under consideration as mitigation strategies:
l Productivity enhancement
l Genetic improvement
l Improved hygienic and sanitation
l Proper veterinary measures
l Suitable breed selection
It is well evident from literature and research experiences that livestock is among the leading contributors towards GHGs emission and thus global warming. To avoid its drastic impact certain mitigation practices should be adopted. Mitigation strategies are multi-faceted including individual improvement of animals through proper management and husbandry; skilled management of manures and in vivo management of respiration in ruminants. Long term planning and strict implementation is direly needed in this regard. Site specific and innovative approaches are beneficial to sustainable livestock production without damaging the environment. Modified and improved production systems will not only decrease the hazardous gases emission but also will improve the system productivity sustainably.
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