Current agriculturalists have inherited a wealth of animal genetic variation in the form of a vast array of locally adapted and modified varieties, strains and breeds of livestock from our farming ancestors. The rate of loss of this resource through dilution and extinction is very high. Immediate action is needed to ensure that it is not squandered, but is passed on to our descendants for whom this resource may be essential to develop new livestock populations in response to changing environmental conditions and unpredictable human requirements.
Conservation may be by the ex situ preservation of cryogenically frozen genetic material (for which a separate FAO manual has been prepared) or the in situ conservation of live populations. The latter is particularly important for species or within geographical regions where cryogenic preservation techniques are not well developed or are not available. It also enables populations to continue to adapt, evolve and be selected for use in their natural environments.
Immediate action should be taken to conserve any population in imminent danger of extinction. All livestock populations should be identified and action taken to describe and characterise them so that their genetic potential, both in their native country and other regions can be known, and to locate those breeds for which conservation is needed.
Populations may be conserved as separate breeds or in breed pools or composites. No more than three or four breeds should be included in a breed composite or pool, and care should be taken to ensure that they are all well characterised prior to pooling. Only breeds with similar characteristics should be included in the same pool.
Minimum population sizes of an effective population (Ne) of 250 animals should form the basis of a conservation programme although populations may recover from much smaller founder groups. Very small populations should be increased in size as rapidly as possible. More effective conservation of breeds for use should involve the conservation and breeding of much larger population numbers involving several thousand animals.
Minimal conservation projects must be very carefully planned to minimize inbreeding and maximize the contribution of each individual to the next generation. In these programmes there can be no room for selection, other than against gross abnormalities. In larger scale conservation projects, selection should be within the adaptive environment and under sustainable management conditions. Selection should be for those characteristics for which the breed was traditionally valued.
In practice, in situ conservation programmes may be organised at a regional, national, or local level. They may take the form of planned breeding programmes on specified conservation farms. This requires land, personnel, capital to purchase stock and a well planned breeding programme for which long term funding must be found and justified. It is equally possible to establish successful in situ projects at a local level using the land, experience and skill of local farmers. These farmer based projects can be funded nationally or locally and can be co-ordinated through centrally planned programmes or through local co-operatives. Such projects can be very effective in conserving breeds in their natural environment in which they can continue to adapt and evolve within sustainable changes in local agricultural practice, and changes in climatic and environmental conditions. They can be funded through subsidies which should be based on the difference between the potential production of the conserved strain and that of the alternative replacement breed or its crosses.