5 - Animal Genetic Resource Conservation and Climate Change in Cambodia: Reducing Livestock to Decrease GHG Emission?

Summary

To meet the demand for staple food in the next 40 years, developing countries focus on the growth of agriculture. However, the United Nations Conference on Environment and Development (UNCED) intensified their campaigns to increase the awareness of policy makers and scientists on the need to consider the impact of agricultural production on the environment. The development of strategies to meet the increased demand for food should, therefore, be based on a sound understanding of the impacts of different types of production systems. The objectives of increasing food production while conserving the functional production system and the environment must be combined.

Conserving and increasing farm animal production may affect the current fragile environment at a considerable level. Technically, microbial degradation of feed in the rumen is characterised by the formation of short- chain fatty acids (SCFA), mainly acetate, propionate and butyrate; gasses, mainly CO₂ and CH₄; and microbial biomass (MB).

In proportion to the amount of feed degraded, less gas is produced if there is high feed conversion into microbial biomass (i.e., high efficiency of microbial production) than under proportionally high SCFA production (Leng 1993., Van Soest 1994). Methane is produced with acetate and butyrate, but not with propionate. Methane is an important GHG. Its atmospheric abundance is being related to anthropogenic sources including rice paddies, biomass burning, ruminants, land fills, coal mining, natural gas systems, and storage of livestock wastes (Hogan et al. 1991). Any reduction in CH₄ emission would be 20–60- fold more effective in reducing global warming than a similar reduction of CO₂ emission (Shine et al. 1990). Recent inventories have suggested that livestock manure significantly contributes to global CH₄ emissions. An increase in both the farm animal population and the use of liquid-based manure management systems was seen as the cause (Safley and Westerman 1992; Husted 1993).

PROBLEM

Animal genetic resources are important assets in the agricultural production system of rural areas. Appropriate uses of these resources in the production system are critical requirements for sustainability.