Livestock (1993) / Chapter Skim
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Executive Summary
Executive Summary
Pages 1-20
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From page 1... ...
As with crop plants, the purpose of livestock genetic resource management is to maintain a reservoir of potentially useful genetic variation culled from the multitude of livestock breeds and varieties within species. Even though there is little danger that the major domestic animal species, such as Bos Taurus (cattle)
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Preserving society's capacity to improve and develop modern livestock requires that actions are taken to prevent the loss of potentially valuable genetic resources. Because future needs cannot be reliably predicted, a broad array of genetic diversity must be conserved.
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With such rapid advances in science and application, it is imperative that policymakers and researchers seize the opportunity now to put into place priorities for the improved preservation and management of livestock genetic resources. GENETIC DIVERSITY OF LIVESTOCK Genetic diversity within a livestock species is reflected in the range of types and breeds that exist and in the variation present within each.
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Given this prospect, consideration of the maintenance of genetic diversity must become part of livestock improvement programs. Origins of Traditional Breeds Hoofed animals, specifically cattle, goats, pigs, and sheep, first began to be domesticated about 11,000 years ago.
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As a result, indigenous breeds lose their genetic identity or disappear. Although the extent and usefulness of genetic variation among most traditional breeds have not yet been fully characterized, the differentiation clearly reflects a wealth of genetic diversity within the species diversity that permits further selection and improvement.
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The international transport of germplasm can be expected to increase. Concurrently, technology advances for storing and transporting semen and embryos have allowed the trend toward widespread use of germplasm from a small number of individuals, which could cause overall genetic diversity to decline.
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The genetic base of these specialized stocks may become more narrow because of intensification of selection and smaller effective population sizes (the number of reproducing individuals in a population)
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Annual losses in the value of meat production alone are estimated at $5 billion. Additional costs come from losses in milk yields, tractive power, waste products that provide natural fuel and fertilizer, and secondary products, such as hides (International Laboratory for Research on Animal Diseases, 1991~.
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From page 9... ...
The range of genetic diversity in livestock species must be saved as a foundation for future improvements and adjustments to changing production conditions. Because the ultimate effects of diminished genetic diversity are hard to estimate, given the unpredictability of future needs, the conservation of livestock genetic diversity can best be considered as a form of insurance.
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TECHNOLOGIES FOR CONSERVING AND USING GERMPLASM Recent technological developments may, in some instances, have a negative impact on genetic diversity by reducing the number of parents required to propagate a population. However, they also open important avenues for expanding the scope and assessing the potential value of conservation efforts.
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It should be possible to screen preserved stocks and, if desired, to extract and use a beneficial gene or genes that may be located in an otherwise undesirable background. For example, the International Livestock Center for Africa, in Ethiopia, and the International Laboratory for Research on Animal Diseases, in Kenya, are cooperatively conducting research to identify the genetic basis of tolerance to trypanosome infection.
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From page 12... ...
METHODS OF PRESERVING ANIMAL GERMPLASM Three basic approaches can be identified for preserving genetic diversity: maintaining living herds or flocks, cryopreserving gametes or embryos, and establishing genomic libraries. The vast majority of livestock genetic resources will continue to be maintained in living herds and flocks, many of which are privately owned.
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will in most situations be appropriate. The effective preservation and management of livestock genetic
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It has also recognized the need for collating information contained in central data bases, and has supported studies to determine how best to establish and organize such data bases. In 1989, the Commission on Plant Genetic Resources of the FAO voted to address conservation of animal genetic resources in addition to plants, thereby demonstrating its recognition of the importance of livestock genetic resources in global agricultural production.
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The data bank will be valuable to educational institutions, governments, commercial interests, and others who are concerned with the conservation of animal genetic resources. RECOMMENDATIONS Livestock genetic diversity is an essential component of livestock improvement programs, especially to meet the future needs of human society.
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An essential component of this process is establishing national and international data bases that maintain information in a readily accessible form. The Animal Genetic Data Bank at the Hanover School of Veterinary Medicine and FAO's world inventory of native livestock breeds and strains constitute a good beginning, but much greater effort is needed to collect information, particularly from developing countries.
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Responsible private efforts to preserve livestock germplasm should be encouraged and offered public support. Research and Technology Development Research on technologies that could benefit preservation and use of animal genetic resources should be continued and expanded.
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Conservation of genetic diversity is a global concern, and given the greater threat to uncharacterized, unimproved livestock populations in developing countries, support from conservation programs by developed nations is essential. Ultimately, livestock production and improvement programs of both developed and developing countries will benefit from international support and assistance and from enhanced international movement of germplasm resources.
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Expansion of its mandate would be needed to include livestock genetic resources, and philosophical conflicts between the needs of agriculture and the organization's environmental priorities are likely. Given the need to establish global leadership in guiding, coordinating, promoting, and instituting animal genetic resource conserva
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In conclusion, a broad base of genetic diversity in domestic animal species must be maintained to provide flexibility to improve livestock for today's production conditions and to meet unforeseen future procluction requirements. Technological advances in identifying and propagating superior types may allow for substantial losses in genetic diversity.
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