Most food of animal origin consumed in developing countries is currently supplied by small-scale, often mixed crop-livestock family farms or by pastoral livestock keepers. The on-going major expansion of the demand for livestock products for food is expected to have significant technological and structural impacts on the livestock sector. The productivity of animal agriculture in developing countries will need to be substantially increased in order to satisfy increasing consumer demand, to more efficiently utilise scarce resources, and to generate income for a growing agricultural population.
Agricultural biotechnology has long been a source of innovation in production and processing, profoundly impacting the sector. Rapid advances in molecular biology and further developments in reproductive biology provide new powerful tools for further innovation. Increasingly, the advanced molecular biotechnology research and development (R&D) activities are conducted by large corporations and are designed to meet the requirements of developed country markets rather than the conditions of small-scale farmers in tropical regions of the world. Whilst the developing countries accommodate an increasing majority of the world's people, farmers and animals, there is a risk that biotechnology R&D may by-pass their requirements.
In this e-mail conference it is suggested to discuss biotechnologies that are either currently applied or are likely to come on stream for use in animal agriculture. The main theme of the conference is the question as to how relevant and appropriate these technologies are to meet the necessary enhancement of animal production and health in developing countries, and which factors determine their adoption or lack thereof.
The question needs to be addressed why exactly this potential is so under-utilised in developing countries. To what extent is the technology transfer, in adaptation and adoption, affected by, e.g.:
Public acceptance or rejection of biotechnology and ethical questions.
When submitting messages, participants are requested to try and ensure that their messages address some of the above elements.
2. Biotechnologies for Consideration
A. Reproductive biotechnologies:
The main objective of biotechnologies in reproduction is to increase reproductive efficiency and rates of animal genetic improvement thereby contributing to an increased output from the livestock sector. They also offer potential for greatly extending the multiplication and transport of genetic material and for conserving unique genetic resources in reasonably available forms for possible future use.
Artificial insemination (AI):
AI has already had a major impact on cattle, sheep, goat, pig, turkey and chicken improvement programmes of developed countries by accelerating breeding progress primarily through increased intensity of selection of males and through diffusion of breeding progress, initially with fresh, and later with frozen, semen, offering rapid world-wide transport of male genetic material. Globally, more than a 100 million AIs in cattle, 40 million in pigs, 3.3 million in sheep and 0.5 million in goats are performed annually. Only in very few developing countries is AI practised to a level that impacts substantially livestock production. What are the reasons that such a powerful technology has not been more widely adopted in developing countries ? What is required to make the technology the same success as in developed countries ?
Embryo transfer (ET):
ET in the mammalian species, enhanced by multiple ovulation and oestrus synchronisation (MOET), allows acceleration of genetic progress through increased selection intensity of females, and freezing of embryos enables low cost transport of genetic material across continents, and also conservation of diploid genomes. MOET may also be used to produce crossbred replacement females whilst only maintaining a small number of the straightbreds. In 1998, worldwide 440,000 ETs have been recorded in cattle, 17,000 in sheep, 1,200 in goats, and 2,500 in horses. About 80 % of the bulls used in AI in the developed world are derived from ET. Despite the potential benefits of ET, its application is largely limited to developed countries. What are the required technical and/or policy elements that will enable developing countries to make use of these technologies on a greater scale ?
ET is also one of the basic technologies for the application of more advanced reproductive biotechnologies such as ovum pick-up (OPU) and in vitro maturation and fertilisation (IVM/IVF), sexing of embryos, cloning, and of transgenics.
OPU and IVM/IVF:
OPU in mammals allows the repeated pick-up of immature ova directly from the ovary without any major impact on the donor female and the use of these ova in IVM/IVF programmes. Making much greater use of genetically valuable females at a very early age may substantially increase genetic progress. What potential uses of these technologies are feasible in developing countries ? What are the required technical and/or policy elements that will enable developing countries to make practical use of these technologies ?
Technologies for rapid and reliable sexing of embryos allow the generation of only the desired sex at specific points in a genetic improvement programme, markedly reducing the number of animals required and enabling increased genetic progress. Sexing of semen using flow-cytometric sorting has decisively progressed in recent years but still with limited sorting rates, even for IVF. Sexed semen could markedly increase genetic improvement rates and have major implications for end-product commercial production. What is the scope for the use of these technologies in developing countries ?
IVM/IVF are a source of large numbers of low cost embryos required for biotechnologies such as cloning and transgenesis. Three different types of clones are distinguished, as a result of: (1) limited splitting of an embryo (clones are genetically identical); (2) introducing an embryonic cell into an enucleated Zona (clones may differ in their cytoplasmic inheritance); (3) introducing the nucleus of a somatic cell (milk, blood, dermal cells), after having reversed the DNA quiescence, into an enucleated Zona (clones may differ in their cytoplasmic inheritance and there is likely to already exist substantial knowledge of the phenotype of the parent providing the somatic cell). Cloning will be used to multiply transgenic founder animals. Cloning technologies offer potential as research tools and in areas of very high potential return. The sampling of somatic tissue may assist collection and transfer of breed samples from remote areas for conservation purposes.
B. Molecular biotechnologies
Various molecular biotechnology applications are available in animal production and health, involving both on-farm production and off-farm product processing applications. In this e-mail conference we will consider on-farm use; only technologies based on DNA procedures are suggested for consideration.
B.1. DNA technologies and animal health
Animal diseases are a major and increasingly important factor reducing livestock productivity in developing countries. Use of DNA biotechnology in animal health may contribute significantly to improved animal disease control, thereby stimulating both food production and livestock trade.
Diagnostics and epidemiology:
Advanced biotechnology-based diagnostic tests make it possible to identify the disease-causing agent(s) and to monitor the impact of disease control programmes, to a degree of diagnostic precision (sub-species, strain, bio-type level) not previously possible. For example, DNA analysis of bovine viral diarrhoea virus (BVDV) has shown to be composed of two genotypes, BVDV1 and BVDV2. Only the latter was found to produce haemorrhagic and acute fatal disease, and diagnostic tests to distinguish between the two are under development. Enzyme-immunoassay (EIA) tests, which have the advantage of being relatively easily automated, have been developed for a wide range of parasites and microbes. Relevance and accessibility of these diagnostic tests to the livestock industry in developing countries are suggested for debate.
Molecular epidemiology is a fast growing discipline that enables characterisation of pathogen isolates (virus, bacteria, parasites) by nucleotide sequencing for the tracing of their origin. This is particularly important for epidemic diseases, where the possibility of pinpointing the source of infection can significantly contribute to improved disease control. Furthermore, the development of genetic probes, which allow the detection of pathogen DNA/RNA (rather than antibodies) in livestock, and the advances in accurate, pen-side diagnostic kits considerably enhance animal health programmes. The conference should establish the status and potential uses of these technologies in developing countries.
Although vaccines developed using traditional approaches have had a major impact on the control of foot-and-mouth disease, rinderpest and other epidemic and endemic viral, mycoplasmal and bacterial diseases affecting livestock, recombinant vaccines offer various advantages over conventional vaccines. These are safety (no risk of reversion to virulent form, reduced potential for contamination with other pathogens, etc.) and specificity, better stability and, importantly, such vaccines, coupled with the appropriate diagnostic test, allow the distinction between vaccinated and naturally infected animals. The latter characteristic is important in disease control programmes as it enables continued vaccination even when the shift from the control to the eradication stage is contemplated. Recombinant DNA technology also provides new opportunities for the development of vaccines against parasites (e.g. ticks, helminths, etc.) where conventional approaches have failed. What is the status and potential for the use of these technologies in developing countries ?
B.2. DNA technologies in animal nutrition and growth
Applications are being developed for improving the performance of animals through better nutrition. Enzymes can improve the nutrient availability from feedstuffs, lower feed costs and reduce output of waste into the environment. Prebiotics and probiotics or immune supplements can inhibit pathogenic gut microorganisms or make the animal more resistant to them. Administration of recombinant somatotropin (ST) results in accelerated growth and leaner carcasses in meat animals and increased milk production in dairy cows. Immunomodulation can be used for enhancing the activity of endogenous anabolic hormones.
In poultry nutrition, possibilities include the use of feed enzymes, probiotics, single cell protein, and antibiotic feed additives. The production of tailor-made plant products for use as feeds and free from antinutritional factors through recombinant DNA technology is also a possibility.
Plant biotechnology may produce forages with improved nutritional value or incorporate vaccines or antibodies into feeds that may protect the animals against diseases.
Rumen biotechnology has the potential to improve the nutritive value of ruminant feedstuffs that are fibrous, low in nitrogen and of limited nutritional value for other animal species. Biotechnology can alter the amount and availability of carbohydrate and protein in plants as well as the rate and extent of fermentation and metabolism of these nutrients in the rumen. The potential applications of biotechnology to rumen microorganisms are many but technical difficulties limit its progress. Current limitations include: isolation and taxonomic identification of strains for inoculation and DNA recombination; isolation and characterisation of candidate enzymes; level of production, localisation and efficiency of secretion of the recombinant enzyme; stability of the introduced gene; fitness, survival and functional contribution of introduced new strains.
Methods for improving rumen digestion in ruminants include the use of probiotics, supplementation with chelated minerals, and the transfer of rumen microorganisms from other species.
B.3. DNA technologies in animal genetics and breeding
Most animal characteristics of interest to food and agriculture are determined by the combined interaction of many genes with the environment. The genetic improvement of locally adapted breeds will be important to realising sustainable production systems.
The DNA technologies provide a major opportunity to advance sustainable animal production systems of higher productivity, through their application in:
i). Characterising and better understanding animal genetic variation;
ii). Manipulating the variation within and between breeds to realise more rapid and better-targeted gains in breeding value; and in
iii). Conserving genetic material.
i) Characterising genetic variation:
The use of microsatellites in genetic distancing of breeds is gaining momentum. While most breeds are located in the developing world, this work is confined to developed countries. How is it possible to more effectively involve the developing country breeds ? Are the current protocols adequate or what further standardisation is required ?
ii) Increasing the speed of genetic improvement of locally adapted breeds:
There are many links in the chain to realising rapid genetic progress in the desired goals, with the objective being to rapidly transmit from selected breeding parents to offspring those alleles which contribute to enhanced expression of the traits of interest. In developing countries, generation intervals are generally longer for all animal species of interest than in developing countries. How can DNA technologies be used to reliably realise intense and accurate selection and short generation intervals and to enable genetic improvement of these many locally adapted breeds to contribute to the required livestock development ?
There is rapid progress in the preparation of sufficiently dense microsatellite linkage maps to assist in the search for genetic traits of economic importance. Can these linkage maps be used to develop strategies of marker-assisted selection (MAS) and marker assisted introgression (MAI) to meet developing country breeding goals ? How should this be approached ? Given the limited financial resources, how might work for the developing country breeding programmes strategically utilise the rapidly accumulating functional genomic information of humans, mice and drosophila ?
Transgenic animals have one or more copies of one or various foreign gene(s) incorporated in their genome or, alternatively, selected genes have been 'knocked out'. The fact that it is possible to introduce or to delete genes offers considerable opportunities in the areas of increasing productivity, product quality and perhaps even adaptive fitness. In initial experiments, genes responsible for growth have been inserted. The technology is currently very costly and inefficient and applications in the near future seem to be limited to the production of transgenic animals as bio-reactors. What is the potential significance of these advanced technologies for developing countries and what are the technical, societal, political and ethical determinants of their application ?
iii) Conserving genetic diversity:
Global surveys indicate that some 30% of all remaining livestock breeds are at risk of loss, with little conservation effort currently invested. The majority of domestic animal breeds are in developing countries. Whilst animals cannot be re-formed from DNA alone, the conservation of genomic DNA may be useful. Under what circumstances should DNA genomic material be conserved and how should this be done by developing countries ? What other information should be retained and what policy issues need to be taken into account ?
Top of page