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Response: Technology and policy options

Society's response to utilization of domestic animal genetic resources ebbed and flowed over the past three decades. In most situations during the 1960s and 1970s, breed substitution through crossbreeding was the most common mechanism used to increase the genetic potential of livestock in developing countries for a specific character (e.g., milk production). During the mid to late 1980s, there was an increasing awareness that indigenous breeds were highly adapted to the rigorous environments in which they were expected to produce. With this realization came a series of initiatives to conserve animal genetic resources. In some countries, for example India, government and non-government agencies have well-developed programmes of support and conservation for local genetic resources. In many others, such infrastructure is absent. This underscores the need for research, documentation and education activities in this area.

The actors. To effectively conserve and utilize animal genetic resources requires a concerted effort by a number of actors (Table 5.6). These actors include individuals (breeders), breed associations, national governmental organizations, and international organizations.

• Livestock owners (breeders) bear the ultimate responsibility for managing the genetic future of livestock populations. Their actions are determined in large part by the expectations of economic returns.

• Breed associations are responsible for maintaining pedigree information, developing breed standards and collecting and analyzing animal performance information. In many cases, the development and functioning of these breed societies have been assisted from public funds.

• National governmental authorities have a central responsibility in the management of animal genetic resources. governments provide many services, including supervision of breed societies, regulation of imports and animal recording. The primary responsibility therefore, to ensure the conservation of the national animal genetic resources rests with governments. In many countries, local zoos are a public enterprise and therefore could play an important official role.

• Government institutions provide a forum for the development of international accords and conventions. They play a crucial role in planning at the international level for the compilation and management of genetic resource databases. They will also be instrumental in the transfer of technology in cryopreservation, DNA techniques and standardization of procedures.

Box 5.6 Breed population size - a critical balancing point.

There are two ways in which population reduction affects genetic diversity: First, certain genes combinations are lost from the population. Second with limited animal numbers in a breed there is an increased probability that parents of any new individual are relate to each other, which increases the inbreeding of the offspring and decreases genetic variability. The impact of small population size on genetic diversity within a population Is also affected by the following:

Generation turnover: Long generation intervals, as In horses, can delay the negative effects of small population size and inbreeding.

Current and prospective changes in population size: If effective population numbers have been declining and are likely to continue downward, then calculations based on current size will underestimate the risk.

Changes in herd structure: the smaller the herd number, the higher the risk to the breed from the termination of any one here.

The extent of crossbreeding: this can remedy the effects of inbreeding but it can also result In a reduction of genetic diversity.

Source: Cunningham, 1995.

As the various actors initiate conservation assessments and efforts, there is a need for a clearly charted course. The first step is a complete inventory of existing breeds and their status in terms of numbers and genetic diversity. To a large extent FAO's programme in domestic animal genetic resources is accomplishing this goal. An evaluation based upon genetic distancing is important for understanding how unique a breed is and for determining how different various breeds are from one another. Using techniques such as genetic distancing also reduces long term conservation costs, because only the most diverse and endangered breeds will be conserved. This type of assessment is only taking from at this point in time and should be encouraged.

Costs of conservation. The preferred path to conserving a breed is to use it in an economically viable fashion. In some countries it may be possible to provide modest subsidies in order to make conservation of key genetic resources possible. In other environments it may be possible to alter technological components of the farming system, which will enhance the performance of the conserved breed and thereby make it economically competitive. In addition to these approaches it must be remembered that zoos have played a critical role in preserving diverse animal genetic resources. They may continue to provide a suitable means for maintaining live animals and also frozen semen and embryos.

The amount of animal genetic resources which can be preserved via in situ or ex situ methods is determined by the costs of preservation and the expected current value of the preserved resources. The biggest problems are long time horizons and uncertainties about current and future values and uses. The financial resources are lacking to assess and preserve all breeds. However, by using DNA techniques, it is possible to assess the genetic differences between breeds and thereby determine which breeds are truly unique and scarce. Although taking such an approach may have a high initial cost, in the long run it requires fewer financial resources as well as allows greatest attention and efforts to be placed upon those breeds which are in critical need of preservation.

Costs associated with the development of databases, DNA analysis, and international protocols and accords fall into the category of protecting or enhancing public goods. However, the maintenance costs of databases could be shared with livestock owners, breed associations, national authorities and international agencies. On a per head basis the costs involved are modest. For example, long term costs for semen and embryos preservation are in the order of one US dollar per unit per year, depending on scale. One-time genotyping the DNA of a breed within a country for across breed comparison costs approximately US$ 1,000 to US$ 3,000 (US$ 5 to US$ 10/head) and does not have to be repeated. To recover these costs fairly modest incremental benefits are required. For example, (Cunningham, 1995) at a discount rate of 7.5 percent, an incremental benefit of 80 times the annual cost could repay a 25 year investment in the conservation of a breed. Thus, a return of US$ 800,000 would be required to recover the costs of a breed conservation programme covering 10,000 animals over 25 years. If we assume that such benefits would impact on ten million animals the incremental yields per animal required to repay the investment would be less than US$ 0.10. This is an estimate of the initial returns to conservation. As the genotype continues to be productive there would be additional returns, which would continue to lower the cost of conservation.

Table 5.6 Relative importance of different actions for different participants in animal genetic resource conservation.

ACTIONS

Breeder/ Farmer

Breeders organization

National authority

International agencies

In situ conservation

***

***

**

*

Ex situ conservation

*

**

***

*

DNA characterization


*

***

*

Databases

*

**

**

***

Box 5.7 Tools for conservation.

1. In situ conservation: Manipulations of animals with a viable population size. To be accomplished by enhancing the economic value of the animals in the rimming system. (For example, selection within populations).

2. Ex situ conservation: Maintain animals by freezing semen and embryos. However, this technology is not adequately developed for at species. Although Sour and animal facility costs are saved the approach requires the continual use of frozen nitrogen and a secure facility.

3. DNA technology: Currently this technology has the ability to provide important information concerning the evolutionary history of a breed or species.

4. Thorough documentation of aft breeds and landraces currently in existence will provide a basis for evaluating breed differences.

5. Development of international accords to provide a framework for global animal genetic resources.


Bread improvement goals. Past attempts at improving livestock productivity in developing countries have focused largely on importation of exotic breeds. This approach was taken, instead of within breed selection, because crossbreeding appeared to be a faster means of achieving increased production. The imported breeds were then crossed with existing genetic stocks and, as a result, in many instances replaced indigenous breeds.

Selection of imported breeds was based upon a partial analysis, which indicated that they could produce higher quantities of milk, meat or wool. However, the analysis lacked a full appreciation for genetic-environmental interactions and lifetime productivity. This practice of selecting for individual production characteristics (growth rates, meat production and/or milk production) versus lifetime productivity and/or biological efficiency, has carried over to selective breeding of indigenous populations. The result is a partial analysis of how indigenous breed types perform. Because the entire process of animal production has not been evaluated these actions have also contributed to the displacement and loss of biodiversity. Furthermore, over the long term most exotic breeds have not been able to maintain high levels of productivity. The result is not only a loss in biodiversity but also a loss in economic returns.

Compounding the problems of partial analysis has been a disregard for genetic traits for fitness associated with the adaptation complex. Animals in a specific environment have developed resistance or adaptation to a full range of environmental challenges; e.g., ticks, internal parasites and temperature (Hammond and Leitch, in press). These characteristics have not been fully accounted for in planning and executing breeding and selection schemes in developed or developing countries.

Figure 5.3 demonstrates how different genotypes respond to different types of environments. By removing environmental stresses the genotype of highly selected breeds can more fully express itself. By viewing breeds in the context of composite productivity, it becomes much more apparent how indigenous breeds (or those breeds which have been selected for a different set of characteristics) can have the potential for higher levels of productivity.

An alternative approach to breeding animals for perceived economic returns and conserving genetic resources is to match genotypes to environments (Box 5.8). Instead of importing a genotype and attempting to modify the environment through increased input levels, indigenous breeds should be used and, where appropriate, pre-evaluated with exotic breeds. The basis for comparing performance should be lifetime productivity (number of offspring per female), economic returns for the herd or flock (vs. individual performance) and biological efficiency (output/input). In essence, such a strategy implies that there can be no general recommendations about breeds without accounting for the specific environment in which they are expected to perform. Furthermore, such an approach would weigh the costs of altering environmental conditions to maintain modern breed productivity levels with minimal costs of environmental change and improving the productivity levels of indigenous breeds. Studies to characterize this re-ranking of genetic types in differing environments are not easy to design or conduct. However, simulation models have been developed which allow a screening of breed types in different environments (Blackburn, 1995).

Policy. To stem the dangerous erosion of domestic animal genetic resources, the following policy options are recommended:

• support implementation of the Biodiversity Convention, which includes development of national and regional infrastructures;

• assess roles of indigenous and non-indigenous breeds in meeting future domestic and export needs for food and other animal products;

• facilitate regional cooperation among countries to achieve economies of scale;

• support international exchange and utilization of animal genetic resources;

• foster public-private sector linkages which enable economically viable gene conservation (e.g., AI companies and zoos);

• eliminate subsidies on, and foreign aid which subsidizes, artificial insemination and breed importation schemes; and

• eliminate all subsidies, which inappropriately favour modern production technologies over traditional ones (subsidized concentrate feed and drugs, credit etc.) as they distort breed choices.

Figure 5.3: Relative breed performance of selected and indigenous genotypes across environments.

Research needs. Using the above example as a basis for determining conservation and better animal breeding practices the following research initiatives are required:

• to shift research focus from individual traits to lifetime and herd productivity using deterministic simulation models and live animal experimentation where feasible;

• to determine, using DNA analysis of genetic variation (genetic distancing), the number of breeds which should be conserved as a priority;

• to develop appropriate selection goals based upon the environmental capacity for animal production;

• to improve understanding of genetic components of adaptation (e.g., tick resistance, utilization of body stores); and

• to develop methodologies to determine the economic value of animal genetic resources.

Improving competitiveness of indigenous breeds.

Box 5.8 Improving competitiveness of indigenous breeds.

AN IMPORTANT tactic for conserving indigenous genetic resources is to make those breeds more beneficial. Combining existing breed attributes with traits that increase the economic value of the breed is such a mechanism. The N'Dama cattle of southern Senegal have traditionally been the most important element in the farming system in the Casamance. In this area, the trypanosomiasis challenge is high, and other breeds cannot survive in that environment. Although the N'Dama is able to withstand the trypanosome challenge their productivity is low: two year calving intervals, low growth rates and milk production averaging about 700 kg per cow. A research programme has been initiated to improve the performance of the N'Dama using feed products which are readily available (groundnut hay, cotton seed meal). By improving the N'Dama's nutrition, performance has been doubled.

Source: Philipsson and Wilson, 1995.

Livestock and greenhouse gases


Environmental challenges
State
Driving forces
Response: Technology and policy options


Environmental challenges

"Global warming" or global climate change have recently become a major concern. There is increasing evidence that global temperatures are rising (0.3C to 0.6C over the last century). This is caused by so-called "greenhouse-gases" trapping radiant heat reflected from the Earth's surface before it is released into space. Global warming has a double effect on agriculture. Agriculture, including livestock, contributes to global warming and, in turn, it is directly affected by the resulting changing climatic patterns. This specific livestock-environment interaction offers, however, considerable scope for mitigating adverse effects on the environment with improved technology, and the development of" win-win" scenarios. The challenge is to identify these win-win scenarios and to develop corresponding sets of action.

State

The greenhouse gases include carbon dioxide (CO2), methane (CH4), ozone (O3), nitrous oxide (N2O) and other trace gases (Bouwman, 1995). Their potential to global warming is greatly different, as shown in Table 5.7, which shows that methane is about 20 times more aggressive and nitrous oxide even 300 times more damaging that carbon dioxide.

Carbon dioxide emissions. Burning biomass is the main agricultural source of CO2 emission. Destruction of global forests produces about 1 to 2 billion tons of CO2 per year. Burning of savanna vegetation, sometimes initiated by traditional herders to get high quality new grass shoots during the dry season, but also practiced by hunters and croppers to clear the land or chase the game, is another important contribution to CO2 emissions.. Although exact estimates are lacking, one estimate (Menault, 1993) puts the annual emission of the savannas at 18 percent of the global agricultural emissions of CO2. Of this, the African continent would produce 43 percent whereas Asia and South America combined produce 39 percent. However, this release of CO2 is usually reabsorbed the next season by the new growth. In addition, increased atmospheric CO2 levels (from 250 to 350 ppm over the last 150 years), mainly as a result of the industrial and automotive revolution, present a specific environmental challenge in that they favour especially the so-called C3 herbs and trees over grasses (Mayeux, 1993). These contribute to bush encroachment and reduce biodiversity in the grassland areas. The increased CO2 level will probably contribute to changes in the structure of the livestock industry. Eckert et al., (1995) estimate that the shift from C4 to C3 plants would result, in the USA, in a shift of livestock production to the north because rangelands in the southern states would become less productive. Mixed species grazing can, however, slow down or possibly halt this shift in vegetation.

Methane emissions. The global average methane concentration is about 1.7 ppmv and is increasing at about 0.8 percent per year (World Bank, 1992). It is a result of human activities such as animal production and manure management, rice cultivation, production and distribution of oil and gas (pipelines) and coal mining and landfills. As shown, livestock and manure management contribute about 16 percent of total annual production of 550 million tons. Increasing methane emissions affect human and ecological health and, because methane has a high capacity to absorb infrared radiation, it is an aggressive greenhouse gas.

Methane emission by livestock is a direct result of the capacity of ruminants to utilize large amounts of fibrous grasses, which cannot be used as human food. Ruminant livestock, such as cattle, sheep and goats have a large anaerobic digestion vessel "the rumen", which contains a large microbial fauna. which ferment and digest roughages. This digestion results in relatively large methane emissions per unit of feed energy consumed. Pigs and poultry cannot digest these fibrous feeds and have therefore relatively low emissions. Thus, ruminant animals, when fed low quality feed, have higher methane emissions per unit of product than better fed animals, although the latter - as has been shown before - often leave other heavy environmental loads in soil and water pollution.

Table 5.7: Global warming potential (GWP) and other properties of CO2, CH4, and N2O.

Gas

Concentration*

Annual increase*

Lifetime (years)

Relative absorption capacity

GWP

CO2

355 ppmv

1.8 ppmv

120

1

1

CH4

1.72 ppmv

10-13 ppbv

12-17

58

24.5 q *

N2O

310 ppbv

0.8 ppbv

120

206

320

* ppmv = parts per million by volume; ppbv = parts per billion by volume
Per unit mass change from present concentrations, relative to CO2.
Global Warming Potential following addition of 1 kg of each gas, relative to CO2 for a 100 year time horizon
* Including the direct effect of CH4 and indirect effects due to the production of tropospheric ozone and stratospheric water vapour.

Source: Bouwman, 1995.

Methane production is determined by two animal production parameters. First, ruminant animals with low levels of productivity use a large fraction of their feed intake for maintenance and, consequently, the emissions are spread over a relatively small output, resulting in a high level of emission per unit of product. More productive animals emit less methane per unit of product. Second, feed quality has an important impact on the level of methane emissions. Very low quality feeds, such as straw and poor forages of sub-humid savannas, have low levels of digestibility, and therefore higher emissions per unit of feed intake.

Low productivity and poor feed quality are characteristic for most of the land-based production systems in arid regions, and to an even greater degree in the humid tropics and sub-tropics, where emissions per unit of product are therefore comparatively high. Grazing and mixed systems in the tropics and subtropics are thus the main contributors to high methane emission levels. Generally, temperate and highland zones have the best quality grazing and other forage resources for ruminants, and therefore lower emission levels. In irrigated areas, fodder is usually of better quality resulting in lower emissions. Annually, livestock produce a total of 86.6 million tons methane of which more than 80 percent (74.5 million tons) comes from digestive fermentation.

Figure 5.4: Sources of methane emission.

Stored liquid manure, produces the remaining 13.1 million tons. Liquid manure management facilities are most commonly used where there is a large concentration of animals at a single facility, such as large dairy or pig farms. Manure that is handled in dry form, spread on fields, dried for fuel, or deposited by grazing animals produces much less methane. Thus, intensive mixed farming and industrial production systems are the main contributors to methane emissions from manure. Because of their large ruminant populations, USA and OECD countries, and the rainfed mixed farming systems and the grazing systems, have the highest methane emissions.

Figure 5.5: Methane production by system.

Nitrous oxide emissions. Nitrous oxide is another greenhouse gas contributing to global warming. Total N2O emissions have been estimated by Bouwman (1995) at 13.6 TG N2O per year, which exceeds the stratospheric loss of 10.5 TG N2O per year by an atmospheric increase of 3.1 TG N2O per year. Animal manure contributes about 1.0 TG N2O per year to total emissions. Indirectly, livestock is associated with N2O emissions from grasslands and, through their concentrate feed requirements, with emissions from arable land and N-fertilizer use.

Figure 5.6: Methane production by species.

Driving forces

Carbon dioxide. In discussing carbon dioxide a clear distinction should be made between temporary and permanent emissions. Many CO2 emissions related to livestock production are part of a normal ecological cycle, with CO2 being released at the end of a growing season, but immediately recaptured again in the next growing season. The emissions from savanna burning fall into this category. Most temperate grasslands therefore have also a neutral balance. Livestock-induced deforestation in grazing systems, driven by road construction, land speculation and inappropriate incentives (Chapter 2), and fossil fuel use in the industrial system, driven by increased demand (Chapter 4) are thus the main sources of permanent carbon release.

Methane. Methane emissions from livestock have been stagnant, despite a growing livestock population. The reasons for this stagnation are twofold. First, increases in productivity lowers emission levels per animal and per unit of product. Advances in feed resources and nutrition, and breed development are contributing factors. Second, monogastric production is growing at a much faster pace than ruminant production. About 80 percent of the total growth of the livestock sector is attributable to pigs and poultry, which emit comparatively small amounts of methane. The growth in meat production is therefore not accompanied by a proportional rise in methane emissions. While methane emission from digestion processes in the rumen is stable, methane emission from manure management is likely to grow fast as production units grow in size and productivity in many countries. This implies that there will be an increased reliance on confined animal production systems and on liquid-based manure management systems which have higher emissions per head and per unit of product.


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