Climate change and livestock : Impacts and mitigation
- Part 3 -

P Mayengbam / TC Tolenkhomba *

Livestock diseases

Temperature rise due to global warming is likely to cause an increase in animal diseases that are spread by insects and vectors (Tubiello et al., 2008; Thornton et al., 2010). The direct effects are related to the increase of temperature, which increases the potential for morbidity and death. Elevated temperature and humidity will favour spread and growth of insects/vectors.

Incidences of both protozoan and viral diseases affecting livestock will spread in susceptible population. Incidences of protozoan diseases like trypanosomiasis and babesiosis are likely to increase in high producing crossbred cattle and may be higher than the present. Climatic conditions favourable for the growth of causative organism during most of part of the year due to temperature rise will facilitate spread of diseases in other seasons and also increase area of their spread.

Efficiency of Production System

At the end of twentieth century the world witnessed a shift in the “centre of gravity” of livestock production, from North to South, from temperate regions to sub-tropical environments. In 1998, India emerged as the world’s largest milk producing country surpassing the United States. Earlier China overtook the United States and the entire European Union in terms of meat production.

These changes are only indicative of the fact that livestock production system efficiency in tropical and subtropical regions is comparable. The Indian livestock production system contributes not only in terms of milk but also for animal power and majority of farms in India are dependent on animal power.

The resource poor farmers under stressful climatic conditions and different agro-ecological regions have tremendous adaptive capacity to changing conditions, but the current climate changes are occurring at the pace not seen historically, therefore, the adaptation ill be less than the pace of changes occurring (Upadhyay et al., 2013).

In general, faster the climate changes, the greater the impact on people, ecosystems and efficiency. People, animals and the natural environment have become particularly vulnerable to the impacts of climate change.

Mitigation measures

There is potential to reduce livestock sector GHG emissions through the implementation of different technologies and practices. However, they are not widely used (Gerber et al., 2013). Some of the technical options for mitigating the impact of livestock on climate change are carbon sequestration, improving diets to reduce enteric fermentation, improving manure management, and more efficient use of fertilizers (Steinfeld et al., 2006; Thornton and Gerber, 2010; UNFCCC, 2008). Mitigation measures need public policy support to e effective (Dickie et al., 2014).

Enteric fermentation

Carbon sequestration can be achieved through decreasing deforestation rates, reversing of deforestation by replanting (Carvalho et al., 2004), targeting for higher-yielding crops with better climate change adapted varieties, and improvement of land and water management (Steinfeld et al., 2006).

Soil organic carbon can be restored in cultivated soils through conservation tillage, erosion reduction, soil acidity management, double-cropping, crop rotations, higher crop residues, mulching and more (Paustian et al., 1997; Steinfeld et al., 2006).

Improving pasture management can also lead to carbon sequestration by incorporating trees, improving pant species, legume interceding, introducing earthworms, and fertilization (Conant et al., 2001). In addition, grass productivity and soil carbon sequestration could be improved by increasing grazing pressure in grasslands that have a lower amount of grazing animals than the livestock carrying capacity (Holland et al., 1992). Improving grazing land management could sequester around 0.15 gigatons CO2-eq yr1 globally (Henderson et al., 2015).

Practices for mitigating enteric fermentation are increasing dietary fat content (Beauchemin et al., 2008; Martin et al., 2010), providing higher quality forage (Hristov et al., 2013), increasing protein content (ICF International, 2013), providing supplements (e.g. bovine somatotropin, feed antibiotics) (Boadi et al., 2004), and the use of anti-methanogens (vaccines to suppress methane emissions; EPS, 2013).

However, there is high uncertainty in the efficacy of these practices because various studies have demonstrated that the initial reductions of enteric fermentation achieved are only temporary (ICF International, 2013).

Manure management

Most methane emissions from nature management are related to storage and anaerobic treatment. Although manure deposited on pasture can produce nitrous oxide emissions, the mitigation measures are often difficult to apply because of the manure dispersion on pasture (Dickie et al., 2014). Therefore, most mitigation practices involve shortening storage duration, improving timing and application of manure, used of anaerobic digesters, covering the storage, using a solids separator, and changing the animal diets (ICF International, 2013).

Adjusting animal diets can also be used as a mitigation measure, by changing the volume and composition of manure. GHG emissions can be reduced by balancing dietary proteins and feed supplements. If protein intake is reduced, the nitrogen excreted by animals can also be reduced. Supplements such as tannins are also known to have the potential to reduce emissions. Tannins are able to displace the nitrogen excretion from urine to faces to produce an overall reduction in emissions (dickie et al., 2014; Hess et al., 2006).

Fertilizer management

Fertilizer application on animal feed crops increases nitrous oxide emissions (Bouwman, 1996). Therefore, mitigation measures such as increasing nitrogen use efficiency, plant breeding and genetic modifications (Dickie et al., 2014), using organic fertilizers (Denef et al., 2011), regular soil testing, using technologically advanced fertilizers, and combining legumes with grasses in pasture areas may decrease GHG emissions in feed production (Dickie et al., 2014).

Shifting human dietary trends

Most studies are focused on reducing GHG emissions on the supply-side of the livestock production system. However, less research has focused on the demand section related to consumption of livestock products. A reduction in meat consumption may significantly reduce GHG emissions because beef accounts for a large portion of GHG emissions from the livestock sector and it is the least resource efficient animal protein producer (Stehfest et al., 2009) and thus the mitigation potential is high for the beef component of the livestock sector.

Conclusion

Rise in temperature due to climate changes is likely to impact livestock production and livestock health. Increase in physiological reactions and energy expenditure at high temperatures will elevate heat loads of animals resulting into decline in productivity (milk, meat, wool and draught power). Higher temperature and prolong period of stress will affect diseases and pest challenges.

Incidences of diseases (parasitic and protozoan) is likely to increase. Inadequate resources and infrastructure will put stress on livestock and livestock production system with further substantial increase. India is likely to face a major water crisis that will severely impact livestock and livestock production system.

In order to achieve the mitigation measures to address climate change and livestock production, these measures should be scaled up through policy. For example, understanding farmers’ perceptions and including them in policy development can improve food security and environmental conservation by promoting widespread practice adoption.

In addition, a comprehensive view of costs, time, and effort required from the producer needs to be included to the policy framework to maintain sustainable production systems.


Concluded ....