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The requirement of livestock products is increasing day by day and is expected to increase significantly in future. Since the developing nations still have unexplored potential, there will be additional increase in demand from them. But to meet the world demands the nations either has to increase the quantity of their livestock, or the quality, viz, production potential.

However choosing either option is not an easy task for these nations because of the adverse effects livestock has on the climate, which is an alarming global issue and needs to be addressed immediately.
            About one-third of the ice free terrestrial surface area of the planet is occupied by livestock, which uses almost 15% of the global agricultural water (World Bank, 2009). As per one estimate livestock are accountable for 20% of rangeland degradation and out of biodiversity of 825 worldwide ecoregions, livestock poses a threat to biodiversity of 306 ecoregions (Le Gall, 2013). The most detrimental impact of livestock on the climate change is through the production of enormous amounts of Green House Gases (GHGs). The agricultural sector, through its green house gas emissions contributes 22% to the total world emissions, out of this the contribution from livestock (including transport of livestock and feed) accounts for 80% of the emissions. (McMichael et al., 2007). The livestock sector has a contribution of 14.5% of all the global anthropogenic green house gas emissions (Henderson et al., 2016). The global warming potential of CH4 and N2O are 25 and 310 times more, respectively when compared with CO2 (Opio et al., 2013). Carbon dioxide from the respiration of livestock, though, is not considered as a net source of GHG emissions (Kyoto Protocol, 1997) but according to studies conducted by British Physicist, Alan Calverd in 2005, CO2 from the respiration of livestock accounts for 21% of anthropogenic GHGs (Calverd, 2005). The figure however was changed to 13.7% after considering some important facts which Calverd has not paid heed to in his studies (Goodland & Ahnang, 2009). As per a study enteric methane contributes 4% to the world methane production (Forster et al, 2007; & Klieve & Ouwerkerk, 2007) The sources of GHGs from livestock rearing are enteric fermentation (90% contributor) and excreta. In one study FAO has predicted that the GHG emissions may get doubled in the coming 35-40 years.

1. GREENHOUSE GAS PRODUCTION BY VARIOUS LIVESTOCK SPECIES:

The intergovernmental panel on climate change of United Nations in a report submitted that the probability of global warming is huge and that the humans are mostly responsible for it (IPCC, 2007). Carbon dioxide, methane, nitrous oxide, hydro fluorocarbons, per fluorocarbons and Sulphur hexafluoride: are the greenhouse gases included by IPCC as the major causes of global warming. Among these methane is produced considerably in huge amounts by livestock and is an important greenhouse gas the levels of which are elevated in atmosphere (Bhatta et al., 2005, 2006a). The greenhouse gases cause warming of earth due to trapping of energy by the GHG particles (IPCC, 2001). The carbon footprint of livestock is greater in developing than in developed countries (Cole et al., 2016). There are four ways by which livestock cause the emission of gases into the atmosphere which include Enteric fermentation, Decaying of dung in absence of oxygen, Increased carbon dioxide (due to various processes involved in livestock production and marketing) and clearing of trees (Leng, 1991). Nitrous oxide and methane are important sources of GHG emitted from livestock through livestock products while in monogastrics, only nitrous oxide is the main GHG emitted. CO2 is not important as far as livestock products are concerned (Vries & Boer, 2009). The major contributor of the GHG emission is Asia pacific (32.74%) followed by Latin America, Europe, Africa and North America. (Key & Tallard, 2012). The total GHG emission in world by livestock species and humans in 1983 is summarized in Table (1). So far as enteric methane emission from different livestock species in India is concerned, Cattle and buffalo together contribute more than 90% and sheep and goat contribute over 7.5%. A detailed account of the emissions by livestock in India is presented in Table (2).
Cattle: Cattle has a major share in GHG emission by livestock which is more than 50%. The milch animals have a lower emission rate as compared to beef cattle because of their preference towards milk production and thus diluting emissions with respect to maintenance requirement. Also cattle reared in grazing system have more emission intensity than those reared in mixed farming system. The contribution of cattle include 2.9 gigatonnes from beef production and 1.4 gigatonnes from milk production. Other Goods and services related like manure contribute about 0.3 gigatonnes.
Buffalo: Buffalo contribute less as compared to cattle prior to their less population although per head emission in case of buffalo is more than cattle. This is because of lower digestibility of feed in buffalo. They contribute over 390 million tonnes from milk production and 180 million tonnes from meat production and 48 million tonnes from other related goods and services.
Small Ruminants (Sheep and Goats): About 475 million tones CO2-eq is released by sheep and goat, 299 million tonnes from meat production and 130 million tonnes from milk production. Compared to Cattle and buffalo, the emission rate is less in small ruminants even though additional emission from fiber production is seen in small animals.
Pig: Pig contributes 668 million tones of livestock emission from meat production. Other main emission sources with respect to pig include feed and manure.
Chicken: Chicken emits 606 CO2-eq million tones, 217 million tonnes from egg production and 389 million tonnes from meat production. The other emission sources include feed production and manure. (FAO, 2013)
The latest information regarding the greenhouse gases emitted due to activities pertaining to livestock species during the period 1995-2005 is given in Table (3).

1. Impact of Livestock on Climate and it’s Repercussions on Biodiversity:

Climate is the average weather. It is the mean of temperature, precipitation, and wind over prolonged period of time. Climate has changed over several years attributing to various phenomena like rising concentration of greenhouse gases which cause global warming owing to the greenhouse effect. The surface temperature of earth has elevated by 1.4°F over last 100 years (Le Treut et al., 2007). The amount of GHG in present era is more than that estimated over last 650 thousand years (U. Siegenthaler et al., 2005). There has been an increase of 80% in greenhouse gases emission since 1970, leading to change of 2838 Mw/m^2 equivalent to atmospheric concentration of 473 ppm CO2e (Butler & Montzka, 2011; & NRC, 2010). A significant portion of these greenhouse gases is contributed by livestock leading to severe consequences, which are harmful to the biodiversity and the climate of earth. The impacts of increased greenhouse gases causing increase in the surface temperature of earth, owing to global warming are as hereunder.
3. a. Impact on habitat and environment:
3. a.i. Desertification: Global warming owing to increase in greenhouse gases along with decreased precipitation will most probably lead to desertification especially in dry lands (Dr. Tim Lane, 2014). The arid area of earth is expanding (Thompson, 2010). This would lead to decreased vegetation, erosion by wind and also water logging (Dregne & Cou, 1992) and would result in food scarcity especially in grazing animals.
3. a.ii. Increased melting of snow and ice: Melting of glaciers and ice caps over last 30-35 years due to continuous global warming is a huge matter of concern (Thompson, 2010). The species of animals which would be severely affected include Polar bears, Seals, Walrus etc, as they would lose their habitat. Melting glaciers are a big threat to wild species because of loss of favorable environmental conditions (Stracansky, 2010).
3. a.iii. Sea level rise: This is the considerable effect of the global warming. The sea level is predicted to be increased to faster rate which would cause submerging of low lying coastal area. From 1880 -2009, there was 21cm increase in sea level. (Church & White, 2011). This would account for huge losses of marine biodiversity.
3. a.iv. Stronger storms and extreme events: Global warming would cause increased disaster probability and intensity. Drought and storms due to continuously increasing global temperature is a probable certainty. (The impact of climate change on natural disasters.Drought causes the maximum damage to the livestock while storms such as hurricanes affect fisheries heavily (FAO, 2015).
3. a.v. Ocean acidification: Increased carbon dioxide leads to acidification of ocean, causing much damage to biodiversity .Oceans absorb much of CO2 emission which form carbonic acid on reacting with sea water (Logan, 2010).
3. a.vi. Smog and Ozone pollution: The amount of Ozone has doubled in concentration from last century due to increase in methane and nitrogen oxide. (West J et al., 2006). Ozone is harmful for livestock, plants and the human beings. It has shown to decrease life expectancy and the yields of key staple crops like maize, wheat etc. (Anenberg et al., 2010; & Avnery et al., 2013).
3. b. Impact on feeds: Feed crops are affected by climate increased greenhouse gases in several ways: The increased temperature and changes in the CO2 levels have brought great changed in the herbage growth, the proportion of grasses to legumes has changed thereby changing the pasture composition owing to the change in climate, increased precipitation in certain areas has led to increase in N leaching in the soil. (Hopkins & Del Prado, 2007). Due to drastic changes in climate, the plants adjust their optimal growth ranges and this leads to change in pasture composition as the species alter their competition dynamics. However in mixed systems, the influence is not that noteworthy as they don’t count of availability of pastures always (Thornton, 2009). Decreased rainfall and increased temperatures can lead to less accessible feedstuff for animals.
3. c. Impact on livestock diseases: There has been a tremendous change in the epidemiology of the infectious diseases prior to climate change. These impacts are both indirect and direct. Direct effects concern mainly with the host immune response, increased pathogenicity of disease causing pathogens or vectors and the reemergence of diseases due to these. Conversely, indirect effects are the different living patterns of present society including sociological, cultural, economic changes which have somehow disturbed the host-pathogen interaction or vector-pathogen development, be in the increased contact of host-pathogen due to migration or reemergence of diseases owing to different livestock practices or the changing biodiversity. Due to increase in the extreme events like floods, drought, cyclones, desertification etc, the risk of serious outbreaks of certain diseases has increased like more flooding can result in more outbreaks of leptospirosis and foot rot (Bett et al., 2016). The major effects on livestock diseases owing to climate change are:
3. c.i. Impact on host immune system: Owing to increased greenhouse gases the increase in temperature more than the optimal range (10-30°C) for domestic animals severely affects their normal physiology, reproduction, feed and water intake, milk production, and immunity (Das et al., 2016). The endocrine functions are also affected due to change in temperature resulting in altered secretion of the hormones. The increased secretion of cortisol from adrenal gland due to change in temperature suppresses immune response in animals thus making it more prone to infectious diseases (Dittmar et al., 2014). Reduced feed intake in animals also causes decrease in immunity. Temperature above 30°C has been seen to decrease feed intake in domestic animals like sheep, goat. (National Research Council [NRC], 1981).
3. c.ii. Impact on vectors and pathogens: The changing climate affects the vector activity, survival, development rates and resistance against different medications. The temperature change mostly affects those pathogens which have a major part of their life cycle in open environment. The effects include higher rate of replication inside vector (Bett et al., 2016).
3. d. Impact on productivity: The climate change may affect livestock productivity and their reproductive performance (Nienaber et al., 1999) by affecting their growth, reproduction, adaptation. milk production (Sejian et al., 2016). Heat stress in animals causes decrease in milk, meat and egg production (Nardone et al., 2010).

1. Mitigation Measures

As per the FAO, the world human and livestock population is expected to double from 2006 to 2050. That implies livestock related GHG emissions will also increase substantially and at the same time it is predicted that the industrial GHGs will drop thus making the livestock related GHGs emissions even more objectionable than their current hazardous levels. (Robert & Jeff, 2009).
4. a Managing the demand for livestock products: The technologies available nowadays to deal with these emissions from livestock sector claim to decrease the non CO2 emissions by less than 20%. So a new strategy to tackle this menace is to reduce the consumption of livestock products. Assuming a 40% hike in global population by 2050 and no advance in livestock related green house gas emissions, in order to stabilize the emissions from this sector there should be a need of decreasing the global meat consumption to an average 90 g/person. This would require reduction of meat consumption especially from the methane producing ruminant animals. (McMichael et al., 2007).
4. b Implementing Carbon taxes: Carbon Tax is a fee implemented on the fossil fuel users for paying the damage their fossil fuel imposes on the climate by releasing carbon dioxide into the atmosphere. Carbon tax in Norway, implemented in 1991 contributed to a decline in onshore emissions of 1.5% and total emissions of 2.3%. (Annegrete & Bodil, 2002). This tax has been instated on the energy sector, but since the emissions from livestock are huge, as a measure to curb the emissions, this can be extended to the livestock sector as well, say, if the livestock producers were priced per head of cattle, relative to the amount of carbon each animal produced, a tax could be applied accordingly. This would automatically lead to the control of animal numbers; i.e., holding a fewer animals with high potential in place of large number of non producing animals.
4. c Livestock Production and Management Systems:
The ruminant production systems contribute 90% to the global GHG emissions (Henderson et al., 2016). There’s a need of introduction of abatement practices that would target enteric CH4 emissions and increase soil CO2 sequestration. Following practices could be followed to serve the purpose.
4. c.i Alteration in feeding practices: Methane production per unit of animal can be decreased significantly by taking measures that would improve the quality of feed offered to the Ruminants (Monteny et al., 2006).
4. c.ii. Feeding of dietary oils: Feeding of dietary oils to ruminants has lead to decrease in the GHG emissions (Henderson et al., 2016). This has been proved by a study in which a mixture of feed additives containing lauric acid, myristic acid, linseed oil, and calcium fumarate was fed to lactating dairy cows. These ingredients were added @ 0.4%, 1.2%, 1.5% and 0.7% of dietary dry matter, respectively. The methane emission (g/d) by the animals show a 10% decline (Ziderveld et al., 2011).
4. c.iii. Feeding of Nitrates: Joblin (1999) suggested three ways of decreasing the enteric methane production: viz; removal of methanogens from rumen, reduction in H2 production and provide a H2 sink. Since Nitrate is an electron sink, it is known to reduce the methane production in Sheep (Takahashi & Young, 1991; & Sar et al., 2005). This was proven by a study in which 22g Nitrate/kg DM in the diet reduced methane emission by 32% in Nellore beef steers fed sugarcane based diets (Hulshof et al., 2012).
4. c.iv. Reducing GHGs from manure management: Managing the nutrition of the animal (Aarnick et al., 2007) and taking measures for better handling and storage of manure (Oenema et al., 2007) can aid in bringing down the GHGs emission from manure. We can decrease the production of CH4 production by following a suitable management system, since the CH4 emission is under anaerobic conditions, storage of the dung in pits or lagoons leads to more CH4 emission from the excreta. However in India (and most of the developing countries) the dung is packed in heaps hence the emission is less since it is only from deeper inner layer only.
4. c.v. Biodigestion of manure: At the time of biodigestion the biogas from the digestion chamber is collected and only a little amount of degradable organic matter remains that could be converted to methane. This leads to decrease in GHG emissions as well. Reduction in the use of mineral fertilizer by 15% leads to decrease in the emission of direct Nitrous oxide by 5%.
4. c.vi Increasing the Milk production: It has also been shown that by implementing strategies that lead to increase in milk production, the GHG emissions (methane and nitrous oxide) could be decreased. One of the strategies is increasing the concentrate intake to 235 kg/year in a cow weighing 500 kg/year (CVB, 2002).
4. d Genetic Manipulations: Various strategies have been adopted to alter the genetic makeup of animals so that there is decrease in the emissions of GHG. A study concluded that the methane emission and production (g/day) are a heritable and repeatable trait (Pickering et al., 2015). Calculation of the genomic breeding values to facilitate the genetic selection has been proposed as a way to reduce GHG emission. Some strategies also aim at altering the genetic makeup of plants taken by Ruminants so as to decrease the GHG emissions. RFI (Residual Feed Intake) is another field which can be worked upon. This is an indirect approach for reducing enteric methane emission in beef and dairy cattle. RFI is moderately heritable (0.26 to 0.43), moderately repeatable across diets (0.33 to 0.67) and is independent of body size and production besides independent of body fatness in growing animals (Basarab et al., 2013).
As per a research conducted by the Indian scientists, the dwarf breed of Cattle, Vechur has shown to emit far less methane than other dairy cows. Though the milk produced by the animal is quite less when compared to other dairy breeds, but the methane gas emitted by Vechur is one-tenth the level of methane emitted by a normal sized cow. Encouraging the breeding of Vechur breed, the levels of methane emitted could be brought down by a significant amount.
4. e Future scope: Work is being done on a vaccine in New Zealand by a policy analyst Kara Lok which could act  as methane inhibitor and would reduce the methane gas emissions by 30% and is expected to be ready in 5-7 years (Yvonne O’Hara, 2017).
About the Global Livestock Environmental Assessment Model (GLEAM)
This model is being developed by FAO since 2009 to address the need of comprehensive tool to access the interactions between the livestock and the environment. GLEAM aims at quantifying the production and the use of natural resources which are being used in the livestock sector. Additionally, the aim of GLEAM is to identify the impacts of the livestock on the environment so as to devise strategies for the assessment, adaptation and mitigation to move towards a sustainable livestock sector (FAO, 2010).

Table 1: The total GHG emission in world by livestock species and humans in the year 1983 Total estimate for emission from domestic animals has uncertainty factor of ±15% (Crutzen et al., 1986)

Species	Methane production (teragrams annually)
Bos taurus	54.3
Bubalus bubalis	6.2
Ovis aries	6.9
Capra hircus	2.4
Camelus	1.0
Equus caballus	1.2
Equus asinus	0.5
Sus  scrofa	0.9
Homo sapiens	0.3
Total	73.7

 

Table 2: Emissions by livestock in India (Kamra, 2014)

Table 3: Information regarding the greenhouse gases emitted due to activities pertaining to livestock species during the period 1995-2005 (Mario Herrero et al., 2016)

 

REFERENCES

Aarnick, A., & Verstegen, M. (2007). Nutrition, key factor to reduce environmental load from pig production, Livestock Sci. 109, 194-203.
Alan, & Calverd, (2005). A radical approach to Kyoto, Physics World. July.
Anenberg, Susan, C., Larry, W., Horowitz, Daniel, Q., Tong, & Jason, J. (2010). An Estimate of the Global Burden of Anthropogenic Ozone and Fine Particulate M.atter on Premature Human Mortality Using Atmospheric Modeling. Environmental Health Perspectives. 118(9), 1189-1195.
Annegrete, Bruvoll, & Bodil, Merethr, & Larsen, (2002). Greenhouse gas emissions-do carbon taxes work? Statistics Norway.
Avnery, Shiri, Denise, L., Mauzerall, Arlene, M., & Fiore, (2013). Increasing global agricultural production by reducing ozone damages via methane emission controls and ozone-resistant cultivar selection, Global Change Biology. 19(4), 1285-1299.
Bett, B., Kiunga, P., Gachohia, J., Sindato, C., Mbotha, D., Robinson, T., Lindahl, J., & Grace, D. (2016). Effects of climate change on the occurrence and distribution of livestock diseases. Preventive Veterinary Medicine. 137, 119–129.
Bhatta, R., Enishi, O., & Kurihara, M. (2006a). Measurement of methane production from ruminents-A review. Asian Australasian Journal of Animal Sciences. 20, 1305-1318.
Butler, J., & Montzka, S. (2011). The NOAA Annual Greenhouse Gas Index. NOAA/ESRL, Global Monitoring Division Website. http://www.esrl.noaa.gov/gmd/aggi/aggi.html.
Church, J. A., & White, N. J. (2011). Sea-level rise from the late 19th to the early 21st century. Surveys in Geophysics. 32(4–5), 585–602. doi: 10.1007/s10712-011-9119-1.
Crutzen, P. J., Aselmann, I., & Seiler, W. (1986). Methane production by domestic animals, wild CVB 2002 Tabellenboek veevoeding. Centraal veevoederbureau, Lelystad, The Netherlands. ruminants, other herbivorous fauna, and humans. Tellus 38B, 271–284.
Das, R., Sailo, L., Verma, N., Bharti, P., Saikia, J., Imtiwati, & Kumar, R. (2016). Impact of heat stress on health and performance of dairy animals: a review. Vet. World. 9, 260–268.
Dittmar, J., Janssen, H., Kuske, A., Kurtz, J., & Scharsack, J. P. (2014). Heat andimmunity: an experimental heat wave alters immune functions in three-spined sticklebacks (Gasterosteus aculeatus). J. Anim. Ecol. 83, 744–757.
http://dx.doi.org/10.1111/1365-2656.12175.
Lane, T. (2014). Desertification: land degradation under a changing climate, Climatica: you and the experts exploring climate change.
Dregne, H. E., & Chou, N. T. (1992). Global desertification dimensions and coasts. In degradation and restoration of arid lands. Lubbock. Texas Tech University.
FAO (Food and agricultural organization), (2015). The impact of disasters on agriculture and food security.
FAO (Food and agricultural organization), (2013). Tackling climate change through livestock. A global assessment of emissions and mitigation opportunities.
FAO Global Livestock Environmental Assessment Model, (2010). Version 2.0, Revision 4, June 2017.
Forster, P., Ramaswamy, V., Artaxo, P., Berntsen, T., Betts, R., Fahey, D. W., Haywood, J., Lean, J., Lowe, D. C., Myhre, G., Nganga, J., Prinn, R., Raga, G., Schulz, M., & Van Dorland, R. (2007). Changes in atmospheric constituents and in radiative forcing. Climate Change; the physical science basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK and New York, NY.
Henderson, B., Falcucci, A., Mottet, A., Early, L., Werner, B., Steinfeld, H., & Gerber, P. (2016). Marginal costs of abating greenhouse gases in the global ruminant livestock sector. Mitigation and Adaptation Strategies for Global change. DOI: 10.1007/s11027-015-9673-9 contact: ben.henderson@csiro.au.
Hopkins, A., & Del Prado, A. (2007). Implications of climate change for grassland in Europe: impacts, adaptations and mitigation options: a review. Grass and Forage Science. 62, 118–126.
IPCC, (2001). Climate change 2001: Contribution of Working Group 1 to the Third Assessment Report of the Intergovernmental Panel on Climate change the scientific basis. In: Houghton, J. T., Griggs, D. J.,Noguer, M., van der Linden, P. J., & Dai, X. (eds) Contributions of Working Group I. Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge UniversityPress, Cambridge, UK, 881 pp.
IPCC, (2007). Climate change 2007. Synthesis Report: An assessment of the intergovernmental Panel on Climate Change, pp: 73, Available at: http://www.ipcc.ch/pdf/assessment-report/ar4/sry/ar4 sry.pdf.
Basarab, J. A., Beauchemin, K. A., Baron, V. S., Ominski, K. H., Guan, L. L., Miller, S. P.,  & Crowley, J. J. (2013). Reducing GHG emissions through genetic improvement for feed efficiency: effects on economically important traits and enteric methane production. Animal 2013 Jun. 7 (Suppl 2), 303-315. doi: 10.1017/S1751731113000888.
Kamra, D. N. (2014). Enteric methane mitigation; present status and future prospects. In: Proceedings of Global Animal Nutrition Conference Bangalore, India, 77–87.
Key, N., & Tallard, G. (2012). Mitigating methane emissions from livestock: a global analysis of sectoral policies. Climate Change. 112, 387-414.
Klieve, A. V., & Ouwerkerk, D. (2007). Comparative green house gas emissions from herbivores. Pages 487-500 in Proceedings of the 7th International Symposium on the Nutrition of herbivores. Meng, Q. X., Ren, L. P., & Cao, Z. J. eds. China Agricultural University Press, Beijing.
Kyoto Protocol to the United Nation Framework Convention on Climate Change http://unfcc.int/essential_bachground/kyoto_protocol/items/1678.php.
Le Gall, F. (2013). Livestock sector trends and development issues. Global agenda of action in support of sustainable livestock sector development. Available at: http://www.live stockdialogue.org/fileadmin/template/doc/2013-Le’-Gall-Steinfeld.pdf.
Le Treut, H., Somerville, R., Cubasch, U., Ding, Y., Mauritzen, C., Mokssit, A., Peterson, T., & Prather, M. (2007). Historical Overview of Climate Change. In: Climate Change 2007: The Physical Sciences Basis. Contribution of working Group 1 to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, United kingdom and New York, NY, USA.
Leng, R. A. (1991). Improving Ruminant Production and Reducing Emissions from Ruminants by Strategic Supplementation. United States Environment Protection Agency, Office of Air and Radiation , Washington DC.
Cheryl, & Logan, A. (2010). A review of ocean acidification and America’s response, BioScience, 60, I 10, 1, 819–828. https://doi.org/10.1525/bio.2010.60.10.8.
Lowni, & Thompson, E. G. (2010). Climate Change;The evidence and our options, The behavior Analyst, Association for  Behavior Analysis, pg 153-170.
de Vries, M., & de Boer, I. J. M. (2009). Comparing environmental impacts for livestock products: A review of life cycle assessments, Livestock Science, journal homepage: www.elsevi e r.com/locate/l i vsci, Accepted 23 November
McMichael, Powles, J. W., Butler, C. D., & Uauy, R. (2007). Energy and Health 5 Food, livestock production, energy, climate change, and Health, 370, October 6, http://www.thelancet.com.
Monteny, G. J., Bannink, A., & Chadwick, D. (2006). Greenhouse gas abatement strategies for animal husbandry. Agric Ecosyst Env, 112, 163-170.
pickering, N. K., Oddy, V. H., Basarab, J., Cammack, K., Hayes, B., Hegarty, R. S., Lassen, J., McEwan, J. C., Miller, S., Pinares-Patino, C. S., & de Haas, Y. (2015). Animal Board invited review: genetic possibilities to reduce enteric methane emissions from ruminants. Animal. Sep; 9(9), 1431 -1440, Published online 2015 June 9. doi: 10.1017/S1751731115000968.
Nardone, A., Ronchi, B., Lacetera, N., Ranieri, M. S., & Bernabucci, U. (2010). Effects of climate changes on animal production and sustainability of livestock systems. Livestock Science 130, 57–69.
National Research Council (NRC), (1981). Effect of enviroment on nutrientrequirement of domestic animals. In: Subcommittee on Environmental Stress,National Research Council (NRC). National Academic Press, Washington, DC.
Nienaber, J. A., Hahn, G. L., & Eigenberg, R. A. (1999). Quantifying livestock responses for heat stress management: a review. Int. J. Biometeorol. 42, 183–188.
Oenema, O., Oudendag, D., & Velthof, G. L. (2007). Nutrient losses from manure management in the European union. Livestock Sci 112, 261-272.
Stracansky, P. (2010). Melting glaciers threaten environment, Aljazeera, 17 november.
Hulshof, R. B. A., Berndt, A., Gerrits, W. J. J., Dijkstra, J., Van Ziderveld, S. M., Newbold, J. R., & Perdok, H. B. (2012). Dietary Nitrate Supplementation reduces methane emission in beef cattle fed sugarcane-based diets/ J. Anim. Sci. 90, 2317-2323. doi: 10.2527/jas2011-4209.
Goodland, R., & Ahnang, J. (2009). Livestock and Climate Change, Nov/Dec www.worldwatch.org.
Sar, C., Mwenya, B., Pen, B., Takaura, K., Morikawa, R., Tsujimoto, A., Kuwaki, K., Isogai, N., Shinzato, I., Asakura, Y., Toride, Y., & Takahashi, J. (2005). Effect of ruminal administration of Escherichia coli wild type or a genetically modified strain with enhanced high nitrate reductase activity on methane emission and nitrate toxicity in nitrate infused sheep, Br. J. Nutr 94, 691-697.
Takahashi, J., & Young, B. A. (1991). Prophylactic effect of L cysteine and Nitrate induced alterations in respiratory exchange and metabolic rate in sheep. Anim. Feed Sci. Technol. 35, 105-113.
Thornton, P. K., van de Steeg, J., Notenbaert, A., & Herrero, M. (2009). The impacts of climate change on livestock and livestock systems indeveloping countries: A review of what we know and what we need to know. International Livestock Research Institute (ILRI), 31 May.
National Research Counsil, U. S. (2010). Advancing the Science of Climate Change. Washington, D.C. National academic press.
Van Ziderveld, S. M., Fonken, B., Dijkstra, J., Gerrits, W. J., Perdok, H. B., Fokkink, W., & Newbold, J. R. (2011). Effects of a combination of feed additives on methane production, diet digestibility, and animal performance in lactating dairy cows, J Dairy Sci Mar; 94(3), 1445-54. doi: 10.3168/jds.2010-3635.
Sejian, V., Gaughan, J. B., Bhatta, R., & Naqvi, S. M. K. (2016). Impact on livestock productivity. Broadening horizons, www.feedipedia.org.
World Bank (2009). Minding the stock: bringing public policy to bear on livestock sector development. Report No 44010 GLB. Washington, DC.
O’Hara, Y. (2017). Vaccine to reduce methane from cows could be 5-7 years away, 16 December, Otago Daily Times, New Zealand.
Gerber, P. J., Steinfeld, H., Henderson, B., Mottet A., Opio, C., Dijkman, J., Falcucci, A., & Tempio, G. (2013). chapter No.4, pp 23-40, Rome.