Impact of Livestock Farming on Climate Change and Its Mitigation Strategies to Reduce Green House Gases.

Impact of Livestock Farming on Climate Change and Its Mitigation Strategies to Reduce Green House Gases.

^*Ratnaprabha M. B. M.V.Sc. (LPM)

Veterinary College, KVAFSU, Nandinagar, Bidar- Karnataka

ratnaprabhamb5@gmail.com

Introduction:

Climate change is seen as a major threat to the survival of many species, ecosystems and the sustainability of livestock production systems in many parts of the world. Average global temperatures have risen considerably, and it is predicted that, increase of 1.8–3.9°C by the year 2100 (IPCC 2007). The reasons for climate change are mainly due to green house gases (GHGs) that is CO₂, CH₄, N₂O & CFCs. Without GHGs average temperature would be -6⁰C instead of 15⁰C. However it has risen 0.6⁰C since industrialization (1800s) & expect to rise 1.4 to 5.8⁰C by 2100 (UNFCCC, 2005).

Globally livestock generates around 45 Crore tonnes of excreta annually and it was estimated that Raising livestock generates 14.5 per cent of global greenhouse gas emissions. Livestock activities contribute about 18% of total anthropogenic GHGs emission from 5 major sectors like energy, industry, waste and agriculture.

The most important greenhouse gases from animal agriculture are methane and nitrous oxide. Methane, mainly produced by enteric fermentation and manure storage, is a gas which has an effect on global warming 28 times higher than carbon dioxide. Nitrous oxide, arising from manure storage and the use of organic/inorganic fertilizers, is a molecule with a global warming potential 265 times higher than carbon dioxide. The carbon dioxide equivalent is a standard unit used to account for the global warming potential (IPCC, 2013).

Livestock excreta contain nutrients (N, P & K) as well as drug residues, heavy metals & pathogen which accumulates in water/soil leads environmental pollution. In India the total livestock population is 536.76 million (DHAD, 2019). Considering the total contribution from agriculture, livestock contributes around 58% of the total emission. However, there is a highly complex paradoxical interrelationship between livestock production and climate change. On one hand, increased livestock production generated increased greenhouse emissions; but, on the other hand, climate change tends to have detrimental effect on livestock production. The effects of climate change on livestock include changes in feed and fodder availability, scarcity in water availability, emerging new animal diseases and outbreaks, and detrimental impacts on animal welfare, production, reproduction, biodiversity etc. Climate-smart livestock farming is one of the promising avenues to reduce the greenhouse gas emissions from livestock farming which exacerbate global warming and at the same time to sustain the improved livestock production.

Status of green house gasses as per IPCC 2014:

• CO₂-76%
• CH₄-16%
• N₂O-6%

As per the GHG Platform India analyses (2015) at the national level, the total livestock emissions contribution was around 9.6% of total economy-wide emissions and 63 % to gross emissions of AFOLU sector. The total methane emissions of India, livestock emissions contributed more than 50 per cent; this is followed by rice cultivation (GHG Platform India, 2019).

The livestock sub-sector contribution in GHG :

• CO₂ – Deforestation for pasture & feed crop land & pasture degradation will lead to increase
• CH₄ – Enteric fermentation & manure represent 80% from agriculture sector emission
• N₂O – most potent among GHGs, livestock contribute two-third of all anthropogenic emission.
• NH₄ – Bedding material and urine of animals are major sources

Fig: 1 Global green house gas emission by economic sector IPCC, (2014)

Table: 1 Green house gas emission in India (Pathak et al., 2010)

• Among the ruminants, cattle contribute most towards the greenhouse effect through methane emission followed by buffaloes, sheep and goat. Per day enteric methane emission of cattle 150.7 gm/animal, buffalo 137gm/animal, sheep of 21.9 gm/animal, goat 13.7 gm/animal.
• Within the livestock sector, the two categories of emissions are enteric fermentation and manure management. Out of the two, enteric fermentation is the dominant contributor to GHG emissions, accounting for around 90 per cent of the emissions from this sector.
• In 2019 the total GHG emissions was 222.63 million tones CO₂ equivalent from livestock. Out of which 201.69 million tones of CO₂ equivalent were emitted due enteric fermentation.
• The negative impact of temperature rise on total milk production for India has been estimated about 1.6 million tons in 2020 and more than 15 million tons in 2050. (National Symposium, NBAGR, 2009). And it also has negative impact on growth rate and reproductive efficiency of animals.
• Methane is responsible for depletion small portion of protective ozone layer. So it is very important to control or mitigate the methane production.

Fig 2: Greenhouse gases incidence of enteric fermentation and manure storage by animal   type, expressed as Giga tonnes of carbon dioxide equivalents (FAO, 2017).

Table: 2 Green house gas emissions from Indian livestock Chhabra et al, (2013)

Impact of Climate Change on Livestock Production.

1. Feed and Fodder scarcity: Changes in temperature, water availability and a higher level of carbon dioxide affect forage quantity and quality in different ways. i.e. for every 2°C increase in temperature is expectedly to reduce the feed availability in arid and semiarid regions.
2. Livestock Diseases: The direct effects are due to a rise in temperature, which increases the morbidity and death rates. The indirect effects are multiplication of microbes, increased incidence of vector-borne and food-borne diseases, decreased host resistance and fodder and water scarcity (Thornton et al., 2009).
3. Animal Welfare: Heat stress certainly affects animal health and welfare. Due to increased frequency and intensity of heat waves and  change in  environmental conditions  affect livestock health by causing metabolic disruptions, oxidative stress and immune suppression which lead to infections and thus high morbidity and mortality.
4. Animal Production: The dairy sector is affected by heat stress which results in low milk production and low milk quality. The poultry sector is also affected by heat stress due to reduction in body weight gain, feed intake and carcass weight (Tankson et al., 2001).
5. Reproduction: heat stress primarily involves changes in ovarian function as well as embryonic development by reducing the competence of oocyte and in turn the resulting embryo. It has been observed that conception rates of dairy cows may drop up to 20–27% in summer. Such cows often show improper expression of oestrus signs owing to reduced oestradiol secretion from the dominant follicle which has developed in a low luteinizing hormone environment

Strategies to mitigate the GHG emission:

1. Nutritional Interventions
2. Managmental Intervention
3. Rumen manipulation
4. Nutritional Interventions:

• Addition of feed additives can reduce the methane emission like Tannins, saponins, essential oils, propionate enhancers, ionophores like monensin and salinomycin.
• Ionophores changes the bacterial population from gram-positive to gram negative organisms with a concomitant change in the fermentation from acetate to propionate. This leads to reduction in H₂  ions for CH₄
• High levels of concentrate feeds in diets increase the propionate production, which decreases H₂ availability for CH₄ production (oat, berseem)
• Grinding forage feed decrease the production of methane by increasing the rate of digestion and flow through the gastrointestinal tract.
• Legume forages decrease CH₄ production in ruminants, due to the presence of condensed tannins (CT), low fibre content, high DMI, and faster rate of passage from the rumen
• Provision of good quality roughage to animals and U.M.M.B that reduce CH4 and increase milk production
• Fat inclusion in the diets causes a decrease in CH4 production.
• Coconut oil, linseed oil, sunflower oil in the feed is effective in CH4 reduction.

2. Managmental interventions:

• Improving reproductive performance of cows leads to lesser replacement heifers, which helps reduce methane emissions.
• Increasing animal productivity and decreasing the number of lower productive animals helps in reduce methane emission.
• Selection of high genetic merit dairy cows helps in potential reduction in methane emissions
• Grazing pressure to be reduced as a means of stopping land degradation, rotational grazing should be practiced
• An integrated approach to production of trees and animals on the same piece of land helps carbon sequestration, improved feed and consequently reduced enteric methane.
• More frequent removal of slurry from the house floor and changing from a slurry-based housing system to a straw-bedded system helps in reduction of ammonia from animal house
• Decreasing the time cattle spend in buildings i.e. Extending the grazing period will reduce ammonia emissions
• Covering the slurry store or farmyard manure (FYM) heap will helps to reduce the ammonia emission
• Storing the dung in the form of a crust, will reduce ammonia emissions by about 50%.
• Slurry band spreading application methods (eg:  trailing hoses and trailing shoes) and shallow injection techniques have been shown to effectively reduce ammonia emissions following land application
• Reductions in ammonia emissions of up to 50% have been achieved by providing an additional 25% of bedding.

3. Rumen manipulation:

• Defaunation (removal of protozoa) has been suggested as a way to reduce CH4 production in the rumen because Up to 37% of rumen methanogenes found endosymbionts with protozoans.
• Saponin containing plants eliminate protozoa in the rumen without inhibiting bacterial activity.
• Immunization of animals against methanogens reduced CH4 production
• Bromoethanesulphonate, amichloral, chloroform, chloral hydrate these are chemical inhibitors of the methanogens.
• Bacteriocins are bacteriocidal compounds that are peptide or protein in nature, and are produced by bacteria. Using of these bacterions is helpful in reduction in the methane production.
• There is another group of rumen microorganisms, the acetogenic bacteria, which have the capacity to convert hydrogen and carbon dioxide into acetate, Increasing the populations of acetogens through exogenous inoculations into the rumen could be useful for competing against methanogens.

Conclusion: Climate change has negative impact on milk production, growth rate and reproductive efficiency of animals. Methane is responsible for depletion small portion of protective ozone layer. So it is very important to control or mitigate the methane production. Major contributor of CH4 are ruminants, emission of the GHG can be mitigated by Nutritional Interventions, Managmental Intervention and Rumen manipulation.

References:

• Abha Chhabra, K. R. Manjunath, Sushma Panigrahy and J. S. Parihar. 2013: Green house gas emission from Indian Livestock. Climate change 117 (1), 329-344, 2013.
• Department of animal husbandry report. 2019.
• Green house gas platform India, 2019
• Intergovernmental Panel on Climate Change. 2013. Summary for policymakers. In: Stocker, T.F., Qin, D., Plattner, G.K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V., Midgley, P.M., editors. Climate change 2013: The physical science basis.  Contribution of Working Group I  to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge (UK)/New York (NY):Cambridge University Press; p. 1535.
• 2017. Global Livestock Environmental Assessment Model (GLEAM). Rome (Italy):  Food and Agriculture Organization of the United Nations (FAO).
• Intergovernmental Panel on Climate Change 2007 and 2014: Intergovernmental Panel on Climate Change
• National Symposium, NBAGR, 2009
• Pathak , Bhatia, N, Jain and Agrwal. 2010: Greenhouse gas emission and mitigation in Indian agriculture-A review: ING bulletins on regional assessment of reactive nitrogen, bulletin 19, 1-34, 2010….
• Tankson, J.D., Vizzier-Thaxton, Y., Thaxton, J.P., May, J.D. and Cameron, J.A. 2001. “Stress and nutritional quality of broilers”. Poultry Science 80(9):1384-9.
• Thornton, P.K., Van de Steeg, J., Notenbaert, A. and Herrero, M. 2009. “The impacts of climate change on livestock and livestock systems in developing countries: A review of what we know and what we need to know”. Agricultural systems101 (3):113-27.
• UNFCCC, 2005: United Nations Framework Convention on Climate Change

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