Successful conservation is a complex task drawing upon the skills and commitment of many different individuals across Canada.
Conservation of rare breeds as live animals has been carried out largely through the efforts of dedicated individuals and non-government organizations. Their activities have conserved populations that might otherwise have become extinct. They have also played a role in education and in bringing to public attention the risk of losing traditional breeds and the associated biological diversity.
Husbandry practices for conservancy herds and flocks differ from those dedicated to continuous selection for farm animal production improvement. The Centre for Food and Animal Research, working with Joywind Farm Rare Breeds Conservancy, Inc., developed a manual presenting the philosophy, framework, strategy and the "how-to" of conservation breeding. As well, producer manuals and a computer monitoring system were created as tools for the further development of satellite on-farm breeding networks for conservation of animal genetic resources. In addition, data management systems for use by conservancy groups have been developed to track and assure parentage of rare breeds held on many farms, particularly where there is no national breed association and recording system.
It appears well beyond the capability of governments to take ownership or part ownership of animals or to set up a continuing program to provide funds for routine maintenance of animals except under some very specific circumstances and for a very short period of time. Live animal conservancy with concomitant ownership is preferably left in the hands of the private sector.
Another aspect of live animal conservation is that emergency response systems need to be developed so that rare farm animal breeds at immediate risk can be protected until evaluated and, if appropriate, a long term home found for them. This will assure that rare genetic resources are protected before their loss is imminent.
Data base establishment and access are areas of concern shared by everyone involved in conservation efforts. A data base for Canadian research animal genetic resources exists, an effort led by the Canadian Council on Animal Care (Shrestha, 1993). Information is being collected on the farm animal genetic resources across Canada with the first publication in 1994. These detailed inventories of breeds of farm animals in Canada can be a basis for establishing which populations are at risk. Information collected will be in a format suitable for transfer to international organizations as part of a world inventory of farm animal genetic resources.
Research and development efforts to date have concentrated on cryopreservation and excellent strides have been made in this field. However, the amount of research funding dedicated to cryopreservation in Canada is limited and further improvements will be slow.
Semen cryopreservation of several animal species has been important commercially for several decades. The dairy cattle industry has established an entire associated industry dedicated to genetic improvement using cryopreservation technology. Frozen semen is used together with herd testing and sire selection to improve Canadian dairy cattle productivity. The technology for freezing cattle semen is solidly based in science and functions well. This technology has also allowed the rapid growth in exports of dairy stock. The freezing of ram semen is feasible but the technology can be improved. Unfortunately, cryopreservation of swine semen has not been as great a success. Still, recent research has succeeded in defining new parameters for freezing and thawing swine semen and commercial breeders are expected to apply this new information. The technology for freezing poultry semen has not been adequately developed. This will be a key area for future research.
Embryo cryopreservation technology for cattle has been widely adopted by the commercial sector for national and international trade. Sheep embryos are not a major part of international trade for Canada and research on cryopreservation has not been a priority. Methodology for freezing swine embryos is not yet adequate and will require extensive research. Poultry embryos, included in the egg with its massive supply of nutrients, are considered impossible to freeze successfully in their normal state.
Unfertilized egg cells of all species have received little attention for cryopreservation. This, along with in vitro fertilization, could result in flexibility in recovering genetic material of selected parentage from frozen ova and semen. Large cells, including ova, tend to be difficult to cryopreserve successfully.
Embryology and cell culture research, underway at several Canadian universities, can also have important effects on the future conservation of genetic resources and their recovery. This has great potential for conservation and use of poultry genetic resources. Germinal and somatic cells can be grown and maintained in vitro in culture media. This technology is developing rapidly. Under certain circumstances, such as through nuclear transfer or injection of cells into developing embryos, cultured cells could serve as a potential source of genetic material that could be cryopreserved and recovered as living organisms.
DNA is easy to freeze and maintain indefinitely. At present there is no technology for recovering, as a living organism, the genetic information stored as the DNA of an individual. As genes are identified, it will likely be possible to remove specific genes from frozen DNA. Using procedures similar to those involved in transferring DNA between species to form transgenic animals, animals may be produced that have a specific gene from cryopreserved DNA of the same species.
Gene banks will be established using several sources of genetic resources, as appropriate cryopreservation and recovery techniques are developed. Animal health considerations make embryos the preferred form of conservation. Embryos can be collected on-farm and can undergo a process to wash the surface free of specific pathogenic organisms. The specific-pathogen-free embryos could then be frozen for long term storage. This is likely less costly and lower risk than moving rare animals to a central location for semen collection.
Despite this, semen remains, at present, the most common means of cryopreservation of genetic resources. The high cost of collecting semen from rare animals, under satisfactory health conditions, will be a factor in how quickly long term storage can occur. Under some circumstances, it may be appropriate to collect semen from rare breeds in situ to avoid risk of loss, even though the process would introduce future risks to use of the semen because of health concerns.
The Joywind Farms Rare Breeds Conservancy Inc. has begun to store cryopreserved genetic resources. The Centre d'insemination artificielle du Québec, as well, has established a gene bank for one specific dairy breed, the Canadienne, in cooperation with the Québec government and the breed association. In time, it is anticipated that many gene banks with coordinated inventories will be established in the public and private sector.
Current technology allows us to delve into the basic structure of life. The continued evolution of this knowledge will improve both conservation efforts and ways of using conserved animal genetic resources.
Accurate rapid methods for determining or proving parentage of pedigreed animals are important for the breeding industry and conservancy efforts. DNA fingerprinting has replaced traditional methods. As knowledge increases of specific alleles that relate to superior production traits, these could be screened as part of the same testing process. The methodology, developed mainly at universities, is being applied through private laboratories.
Measuring genetic distance between populations is now a reality using modern technology. DNA fingerprinting is a valuable technique for finding the degree of relationship between populations. Other technologies include the micro-satellite technique, which is probably more accurate than DNA fingerprinting although it takes more time and resources. These techniques are useful tools in determining relative priorities for conservation efforts. For example, with this information, efforts can be concentrated on populations more distantly related. Private laboratories now have the capacity to apply the technologies developed at universities and government laboratories.
Identification of genetic markers provides information on the presence or absence of specific genes in an individual. Variations in specific genes, detected directly at the DNA or gene product level, are associated with differences in animal traits. Breeds with distinct traits will be important sources of DNA for gene mapping and the identification of markers for specific genes. Once markers are available, various populations can be screened for the gene for the specific trait. Research in these areas is slow and costly. Strains of animals, selected for specific traits, are required to relate the resultant DNA patterns to the traits of interest. This provides further incentive for preservation of unique genetic stocks in Canada.
Gene mapping has received major attention in several countries, notably the United States. The major objective of animal gene mapping is to develop a map of evenly-spaced, highly polymorphic markers using standard reference populations. The availability of such a gene map will allow the identification of genomic regions that contain quantitative trait loci that have a major influence on economically important quantitative traits.
Most of such traits are influenced by multiple genes. The present knowledge of such loci and of the architecture of quantitative traits is only rudimentary. Identification of DNA markers associated with specific loci will allow their use in marker-assisted selection and will eventually lead to map-based identification of the various loci. Once identified, they can provide further opportunities for understanding their function and for their genetic engineering. The animal breeding industry is supportive of the concept of marker-assisted selection. It is seen as a further opportunity for Canadian agriculture to maintain its competitive position.
Transgenic animals are a reality and may become extremely important in the future. researchers are optimistic that transgenic animals, resistant to specific diseases and able to transfer this resistance through reproduction to their offspring, can be produced. The potential benefits through savings in handling and injecting animals with vaccines or antibacterial agents could be important to producers. As well, disease resistance contributes to the well-being of animals and results in less risk of food residues of concern to consumers. The techniques used to develop transgenic animals have potential as a means to recover specific traits from cryopreserved DNA, once the locations of specific genes are identified. DNA in storage could thus serve as a source of a specific trait that may be required in the future.
Several other technologies, which are interrelated but independent, are essential in animal conservation and use of animal genetic resources:
New reproduction technologies enable the rapid increase in numbers of rare animals through multiple ovulation and embryo transfer to same species donors. Identical animals containing, for example, a rare gene, could be cloned and increased in number. As sexing becomes reliable, selection for male or female offspring will also become possible. Agriculture and Agri-Food Canada, several universities and private companies are conducting research relevant to this area. While such cloning can be applied to greatly narrow the genetic base, it can also be use to provide multiple, genetically identical, rare animals to avoid inadvertent loss of genetic resources through disease or accident.
Canada ha a strong industry capability in new reproductive technologies with local veterinary practitioners performing super ovulation, embryo collection and transfer in cattle. Embryo cloning through micro-surgical splitting of embryos is a relatively crude procedure and results in a damaged zona pellucida that may have implications in international markets for disease control. The more advanced technique of embryo cloning through oocyte enucleation is limited to a few laboratories in Canada. The procedure is costly and the complex steps need scientific investigation to assure a higher level of success and reproducibility of results. These powerful technologies are the tools for the recovery of cryopreserved genetic resources as living animals.
The cattle industry is using embryo transfer techniques along with multiple ovulation to determine how much faster genetic progress can be made compared to conventional sire proof and artificial insemination techniques. A pilot dairy cattle study using multiple ovulation embryo transfer is now under way with support from the breeding industry (led by the Canadian Association of Animal Breeders) and the Natural Sciences and Engineering Research Council. While providing opportunities for rapid genetic improvement of animals, it is important that technology be applied carefully to avoid further narrowing of the genetic base.
Research on reproductive physiology in Canadian universities and Agriculture and Agri-Food Canada is providing a sold base for the future use of conserved farm animal genetic resources. The knowledge of ovulation, fertilization, embryo transfer and implantation and all of the related biochemistry and physiology, in general, represents an essential core of information and techniques that will aid in the future use of conserved animal genetic resources.
New methods for developing veterinary biologics for disease prevention, such as the development of specific vaccines, are critical for a sound animal industry involved in nation and international trade in genetic resources.
New veterinary biologics, using only part of the genome of the disease organism, have been developed that are safer and more specific. The avoidance of risk of infection by using only part of the pathogen genome as the antigen is a distinct advantage. Many such targeted biologics can be expected to improve animal health which, in turn, is critical to the conservation effort. Movement of live animals and cryopreserved animal genetic resources can have serious negative aspects if disease is transferred concurrently. The private sector, universities and Agriculture and Agri-Food Canada's Animal Health Laboratories are conducting research on veterinary biologics.
Advanced diagnostic kits that provide accurate, rapid detection of diseases are important to maintain Canada's outstanding animal health status. Biotechnology is helping create diagnostic tests that are more specific, reproducible and rapid. These new techniques offer opportunities for control of disease and disease-causing organisms that should continue to keep Canada in the forefront of healthy animal populations and a safe food supply, and give Canadian farm animal genetic resources access to most parts of the globe. Precise tests will help prevent inadvertent transfer of disease-causing organisms through conservation and use of genetic resources.
As Canadians look to augmenting existing sources of animal genetic resources from other countries, precise and accurate test are critical to assure safety of the animal population in Canada. Agriculture and Agri-Food Canada's Diseases Research Institute is a world leader in research on animal disease as it relates to international movement of animal genetic materials.
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