Vet. World, 2012, Vol.5(4): 244-247 REVIEW Reducing the Livestock related green house gases emission

Cattle rearing generate more global warming green house gases than driving cars. These green house gases leads to changes in the climate. This climate change affects the livestock, man and natural environment continuously. For this reason it is important for livestock farmers to find the ways which minimize these gases emission. In this article the causes of climate change and effects, measures to be taken by farmers and their efficiency in reducing green house gases emission were reviewed briefly to make the farmers and students aware of the reduction of global warming green house gases and measures to be taken for reducing these gases.


Introduction
of land used.Garnett (2007) identifies four main approaches to mitigatigating livestock green house Livestock Production contributes to climate gas impacts.These approaches focus on the areas of change when the green house gases methane, nitrous husbandry (Feed, genetics and lifespan), the oxide and carbon dioxide are produced and released management system, the number of livestock and into the atmosphere.Ruminants are major culprits of managing the output (manure).the production of methane.It is therefore important for livestock farmers to try and find ways of reducing Climate change causes and effects these emissions.Greenhouse gas emissions may be The climate change is considered to be a threat to reduced by improving feeding practices, increasing the earth because of the effects that an increase of the productivity through breeding or by reducing earth's temperature.The earth's surface is heated by livestock numbers.In order to identify what impact the visible radiation from the sun as well as by infrared livestock has on climate change is known by its carbon radiation emitted by the atmosphere.The flow of foot print.A carbon foot print is defined as the total energy from the atmosphere to the earth's surface is amount of greenhouse gases produced directly and referred to as the "green house gas effect".There are indirectly from the Livestock is usually expressed in gases in the atmosphere that absorb part of the equivalent tones of carbon dioxide (Peterson and radiation emitted back into space by the warmed earth Rohrer 2010).Greenhouse gases (GHGs) are gaseous and these are called green house gases (GHG).The components of the atmosphere that absorb solar greater proportions (about 96-99%) of the gases energy reflected from the earth's surface.This energy (nitrogen (N), oxygen (O ), and argon (Ar) that make 2 is transferred to the major non GHGs (nitrogen (N) and up the atmosphere do not absorb or emit infrared Oxygen (O ) resulting in an overall temperature 2 radiation.The remaining constituents of the increase in the lower atmosphere (De Klein et al. atmosphere are responsible for the greenhouse effect 2008).The main GHG emissions associated with .These are primarily water vapour and carbon dioxide livestock production are carbon dioxide (CO ),   gases make up about 0.05% of the atmosphere from livestock are measured either in terms of kg CO however, they have a part to play in atmosphere concentrate fed.A significant amount of fermentation (Dessler and Parson 2010).Of these trace gases, CO 2 takes place in the rumen of ruminants that results in has the largest share and is the largest contributor to relatively large amounts of methane emissions per unit the green house effect after water vapour.The next of feed energy consumed ( Sejian et al. 2010 ).The largest is methane (CH ) and it absorbs infrared some 4 amount of emissions also differs between developed 20 times more than CO on a per molecular basis.and developing countries (Table 1 ).Cattle produce the Smaller greenhouse contributions come from nitrous most greenhouse gas emission among ruminants oxide (N O), chlorofluorocarbons (CFC) and related Livestock, man and the natural environment are new and more aggressive pests and diseases.At the same time there may also be longer growing seasons Measures to be taken by farmers and their and opportunities of growing wider range of crops.

efficiency in reducing GHG emission
Changes in annual rainfall amounts and patterns, more The mitigation of greenhouse gases from livestock frequent extreme weather conditions, rising sea level due to melting polar ice caps and changes in the could be done by reducing emissions (efficient ecosystem are other outcomes of climate change. management of carbon and nitrogen flows in the (Thornton and Gerber, 2010) observed that the livestock system), enhancing removals (carbon livestock food chains are major contributors to sequestration and building carbon sinks) or avoiding greenhouse gas emission.(Steinfeld, 2006) also or displacing emission(crops and residues from the attributes a larger proportion of green house gas land are used as a source of fuel there by displacing emissions from fossile fuels) (IPCC 2007).Practices emissions in agriculture directly or indirectly to to reduce GHG emissions from livestock can be livestock production.He refers to the following as grouped as: improved feeding practices, use of livestock related sources of green house gas specific agents or dietary additives, longer term emissions: enteric fermentation and respiration, management changes and animal breeding (Garnett animal manure, livestock related land use change, deforestation linked to livestock, livestock related 2007; IPCC 2007).release from cultivated soils, feed production, on farm Improved feeding practices: Methane emissions fossil fuel use and post harvest emissions.(Garnett from livestock are mainly a result of enteric fermen-2007) states that livestock reared in extensive systems, tation and eructation of methane represents a loss of such as ruminants, tend to have a lower per area energy to the animal (Gill et al. 2010).Mitigation footprint than those in intensive systems like poultry options for enteric fermentation may either be aimed and pigs, but have a higher footprint when expressed at an increased animal productivity such as increasing in terms of per kg of product.However livestock not number of lambs produced or aimed at an increased only provide food , but have other contributions to the animal productivity such as increasing number of environment such as the role they play in maintaining lambs produced or aimed to effect rumen functioning ecosystem services and in the biodiversity of the land like increased levels of starch or the use of additives.scape .Ruminants are also able to make use of plants Garnett (2007) says that green house gases may be that grow on non arable land and to consume reduced by modifying the feed in such a way that the agricultural byproducts that humans cannot make use diet is adjusted to meet the nutritional needs more of; meaning that they can utilize land that otherwise closely, by breeding new strains of grasses and cereals, would not be suitable for food production (Garnett improving pasture quality and by adding various 2007, Pitesky et al 2009).nutritional supplements.

The amount of methane emissions differs in
Feeding more concentrates: What the animal is fed ruminants depending on factors such as animal will have a bearing on the amount of enteric and faecal species, breed, PH of rumen fluid, methanogen methane emissions as well as the nitrous oxide emitted population, composition of diet and amount of .whentrying to reduce these greenhouse gas emissions (condensed tannins, saponins or essential oils) and through the adjustment of feed the main focus is on the propionate precursors (fumarate and malate).Vaccines balance between proteins, starch and fibre in the diet.are being developed that contain an antigen derived This is because these have an influence on the levels of from methanogenic bacteria and an immunogenic methane and nitrous oxide that will be produced.preparation that reduces the activity of rumen protozoa Methane emissions may be reduced by feeding more (Sejian et al. 2010).Bovine somatotropin (bST) and concentrate and reducing the intake of forage (IPCC hormonal growth implants do not specifically suppress 2007).This is because the fraction of feed converted to methane formation but improve the animals performethane decreases when feed intake and feed quality mance and thereby reduce emissions per kg of product increase (Garnett 2007).Feed conversion efficiency is (Garnett 2007;IPCC 2007).improved when animals are fed concentrates and Long term management and animal breeding: In growth rate improves.They reach slaughter weight dairy cows, increasing the productivity through breeding sooner resulting in fewer emissions.
and the use of better management practices like With N O the issue is not only about reducing 2 reducing the number of replacement heifers often the quantity of nitrogen that enters the system but reduces methane out put per unit of product that is about how efficiently the nitrogen inputs are converted produced (IPCC 2007).According to (Eckard et al into useful nitrogen outputs rather than being 2010) it was observed that there are variations between converted into urea and faeces.One way would be to animals in the methane emissions per unit of feed optimize the protein intake to reduce the N excretion intake and these variations suggest that there may be and nitrous oxide emissions.As changes are made to heritable differences in methanogenesis.N O emission from ruminants through the increase of 2 Reducing livestock numbers could be the best starch or sugar content relative to protein, this will also possible solution in countries where there are large have an effect on the reduction of methane emissions livestock populations and who want to reduce their because the cause of emissions is inadequate digestion livestock related green house gas emissions (Sejian et (Garnett 2007).
al 2010).However this is not an option in countries Improving pasture quality: Forage quality may be where livestock plays a large role in the contribution of improved by feeding forage that has lower fibre and national income.If productivity increases through higher soluble carbohydrates.Cellulose and heminutritional and breeding strategies, the number of celluloses ferment more slowly than non structured livestock can be reduced without losing the quantity of carbohydrates thereby yielding more methane per unit meat that is currently produced (Garnett 2007). of substrate digested (Eckard et al.2010).There are Another option would be to reduce the number of lower methane emissions when higher proportions of unproductive livestock.This may improve productivity forage legumes are in the diet partly because of the as well as reduce emissions.lower fibre content , the faster rate of passage and also

Conclusion
the presence of tannins (Eckard et al. 2010).Also, the nutrition that can be derived from legume forage is Several methods where indentified as measures superior to that which can be found in grass only for reducing greenhouse gas emissions in ruminants.pastures due to the high protein content (Garnett These include improving feeding practices by increasing 2007).Improving pasture quality, particularly in less concentrates and reducing forage, improving pasture developed regions improves animal productivity and quality or the inclusion of nutritional and other reduces the methane emissions.
supplements such as ionophores, antibodies and oil other management practices such as improving Nutritional and other supplements: One practice productivity through breeding and reducing livestock is the inclusion of oils and oil seeds to the diet (IPCC numbers may also reduce green house gas emissions.

2007). The addition of unsaturated fats such as
Better ration formulation to balance nutrients with real coconut oil to the feed ration keeps the energy demand can result in more efficient use of nutrients intensity of the diet high, reduces the need for grain and lower cost of production.Scientific development based concentrates and also aids in the digestibility of in feed formulation, improved animal genetics and fibre (Garnett 2007).
changes in forage production could if promoted and There are a number of additives that have been encouraged continue to reduce the amount of GHG proposed for the reduction of methane emissions.
released.These are ionophores, antibodies, halogenated compounds

2 (
CO ) along with some other trace gases.These trace 2 Methane (CH ) and nitrous oxide (N O). Emissions

2 followedTable- 1 :
by sheep, goats and buffaloes.synthetic chemicals and ozone (O ).The earth's 3 Average estimated methane emission temperature continues to rise as the concentration of rate through enteric fermentation for ruminants these gases continues to increase.(adapted from sejian et al 2010).