Emerging Technologies to Benefit Farmers in Sub-Saharan Africa and South Asia (2009) / Chapter Skim
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6 Technologies for Improving Animal Health and Production
6 Technologies for Improving Animal Health and Production
Pages 177-210
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From page 177... ...
. Animal protein plays an important role in human nutrition in subSaharan Africa (SSA)
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From page 178... ...
System modeling may be one way to envision the effects of interventions, not only on improving animal productivity but also on increasing income, reducing poverty, and preventing environmental damage associated with livestock production (Box 6-1) (Charles Nicholson, Cornell University, presentation to committee, October 15, 2007)
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From page 179... ...
Peri-urban swine and poultry systems are already a major source of food for city dwellers, but because of the hefty initial capital requirements and environmental considerations they are unlikely to become pathways out of poverty. Improving Animal Nutrition Many of the animals raised by small farmers in SSA and SA suffer from poor nutrition.
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From page 180... ...
Livestock production is the primary food- and income-generating activity for the people in those areas. When market values were assigned to home-consumed goods in a study of the Gabra of northern Kenya, 76 percent of the total was from home-consumed milk and meat, and 21 percent was from goods purchased with revenue from livestock sales, so only 3 percent of household consumption was from non-livestock sources (McPeak, 2003)
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From page 181... ...
Dryland livestock production is heavily affected by low and variable rainfall and is thus vulnerable to the effects of climate change. In harsh environments, survival of animals and their owners depends on access to somewhat less marginal areas for part of the year.
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From page 182... ...
. Research to understand smut biology and to develop resistant strains of Napier grass is important for the rapidly growing dairy industry in the Kenyan highlands.
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bitmap image NOTE: 52 percent dry matter digestibility and 8 percent crude protein. SOURCE: Reprinted from Peter J
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Increasing the efficiency of the ruminal mi croorganisms that play important roles in fiber digestion and nitrogen metabolism will improve animal productivity. When Hungate (1966)
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From page 185... ...
. Existing and evolving Technologies For Improving Animal Germplasm Since the beginning of domestication of animals, substantial progress has been made in improving their characteristics as food and fiber producers by selectively mating individual animals that had advantageous traits (phenotypes)
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From page 186... ...
That kind of effort typically takes place in breeding centers, where resource populations of animals can be developed over a decade or two and individual phenotypes can be collected and recorded to make it possible to identify genetically superior animals (Meuwissen and Goddard, 2000, 2001)
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From page 187... ...
National programs to improve milk and meat production have been initiated and are being termed the "white" and "red" revolutions, respectively, in keeping with the name of the Green Revolution. Genetic improvement for production traits and disease resistance in buffalo does not benefit from the availability of the powerful genomic tools recently generated for domestic cattle in the United States, for two main reasons: the areas of the world where buffalo are economically important lack the financial resources for genomic research, and the application of genomic research to identify genetically meritorious individual animals can be applied only within families of animals.
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From page 188... ...
Most important, it would provide a tool to identify genetically superior animals without having to develop the enormous infrastructure currently used in the developed world. Genetic Engineering For the first 8 to 10 millennia since animal domestication began, selective breeding has been the method by which desirable phenotypes were enriched in a population.
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From page 189... ...
There are dozens of examples of successful application of genetic engineering to protect mice, and many are expected to be predictive of outcomes of transgenic livestock experiments. However, to date there is only one example of genetic engineering that has protected a livestock species from disease (Wall et al., 2005)
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From page 190... ...
If livestock could be protected against these insect vector-borne diseases, animal lives would be saved, and vast regions of western Africa that are now restricted by such diseases could be opened to livestock production. not been fully explored, possibly because of a number of potential hurdles (Silva et al., 2002)
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From page 191... ...
. Fundamental Research Needed for Genetic Engineering Before genetically engineered animals can be produced, it is necessary to have a precise understanding of the reproductive physiology of the breeds of interest and protocols for processing their gametes and embryos.
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From page 192... ...
to the water buffalo. It is clear from the current scientific literature that the general characteristics of domestic cattle's reproductive physiology are similar to those of the water buffalo, but specific differences require additional breed-focused research to optimize control of reproduction and in vitro viability of gametes and embryos (Saikhun et al., 2004; Boonkusol et al., 2007; Drost, 2007)
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From page 193... ...
Spermatogonial Stem Cell Transplantation The use of an emerging technology called spermatogonial stem cell (SSC) transplantation may be able to overcome the infrastructure and technical skill deficiencies that will inhibit subsistence farmers from taking
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From page 194... ...
; Bos taurus fluorescently labeled cells were found in the testes of recipients up to 6 months after transfer. It is envisioned that once this technology has been refined and adapted to local breeds, SSCs harvested from males with superior genetic merit will be distributed to males of average genetic merit but good libido.
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From page 195... ...
It will be necessary to confirm that SSC transplantation can be implemented in the breeds and species of interest in SSA and SA and, if so, that it can be optimized for each species. Improving Animal health Improving the health of animals can have a substantial impact on the livelihood of farmers, especially subsistence farmers that rely on animals for labor, food, and additional income.
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From page 196... ...
Chapter 2 describes the long list of disease problems in SSA and SA. Estimates of losses due to disease in the regions are not well quantified, although one estimate of the annual economic loss due to animal diseases in SSA is around US$40 billion, or 25 percent of the total value of livestock production.
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From page 197... ...
. The use of genetic engineering methods has dramatically improved vaccine production compared with conventional methods of developing live attenuated and inactivated pathogens.
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From page 198... ...
Plant-Based Expression System for Vaccine Development Genetic engineering also has made it possible to use plants as factories for pharmaceutical protein production. Unlike bacterial cells, plants are capable of some post-translational modification and other assembly steps that are needed for biological activity in complex multi-component proteins, such as antibodies.
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DNA Vaccines DNA vaccination stimulates the immune response by introducing into the host naked DNA that codes for antigens of a pathogen. The protein synthesis machinery of the host cell expresses the antigen and stimulates a
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Most of the experimental DNA vaccines have not shown as great protective immunity as conventional vaccines, but new technologies, such as the coating of colloidal gold with DNA, that are in development could improve effectiveness. If future research can deliver a DNA vaccine that offers protective immunization, this approach would add flexibility to the custom designing of vaccines for regional needs.
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From page 201... ...
, are needed for disease detection and vaccination campaigns. Other similar rapid pen-side tests for the recognition of infectious diseases have been developed and are in use, such as the field diagnosis of human and avian influenza outbreaks.
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From page 202... ...
For example, although it is not difficult to find conventional vaccines for many major animal diseases, it is not clear that vaccines based on pathogen serotypes in the industrialized world would necessarily provide protection to animals in SSA and SA, because a given causative agent might have different immunogenic characteristics in different regions. Moreover, most vaccines have not been tested on the indigenous animals to be protected, and knowledge of the diversity of the major histocompatibilty complex in a region must be accounted for.
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From page 203... ...
The use of preimmunization, or the deliberate infection of animals with viable pathogenic organisms followed by a treatment with chemotherapeutic agents, for several homoparastic diseases such as Anaplasma marginale, Babesia bovis, Ehrlichia ruminantium, and Theileria annulata in SSA and SA are not safe technologies because they do not propagate the infectious organisms to naïve populations. In this respect, live attenuated vaccines provide better immunity than subunit or killed vaccines.
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1996. Reconstitution of spermatogenesis from frozen spermatogonial stem cells.
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2007. Advanced reproductive technology in the water buffalo.
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1992. Current status and potential of embryo transfer and reproductive technol ogy in dairy cattle.
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1991. Generation of transgenic dairy cattle using in vitro embryo production.
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2007. Efficient generation of transgenic rats through the male germline using lentiviral transduction and transplantation of spermatogonial stem cells.
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Pp. 357-372 in Applications of Gene based Technologies for Improving Animal Production and Health in Developing Coun tries, H
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2004. Influence of genetic merit on reproductive performance of dairy cattle on commercial farms.
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