I. Bodó 1
1 Department of Animal Husbandry, University of Veterinary Science, PO Box 2, H-1400 Budapest 7, Hungary.
During recent decades the idea of conservation of animal genetic resources has become more and more established in animal breeding, both in theory and practice.
Conservation means the management of the human use of the livestock so, “that it may yield the greatest sustainable benefit to present generations while maintaining its potential to meet the needs and aspirations of future generations” (IUCN definition)2.
2 The definitions are adapted by IUCN, UNESCO, FAO, UNEP, WWF (see Appendix I, Bodó, Buvanendran and Hodges, 1984)
According to this definition, conservation touches the animal science and husbandry as a whole because without this attitude the future reserve supplies of livestock for mankind would be rapidly consumed and exhausted.
Preservation, which is the topic of this paper, has a narrower sense, referring to the FAO definition2: “The aspect of conservation by which a sample of animal genetic resources population is designated to an isolated process of maintenance, by providing an environment, free from the human interference which might bring about genetic change. The process may be in situ whereby the sample consists of live animals in a natural environment, or it may be ex situ, whereby the sample is placed, for example, in cryogenic storage.”
Thus, the purpose of preservation is to maintain animal populations without genetic change as far as possible. There are two basic methods for preserving genetic material: ex situ and in situ. The cryogenic storage of semen, embryos, ova and DNA belongs, first of all, to the ex situ methods, and keeping of living animals in small experimental yards or cages can also be allocated to this group of preservation. The in situ preservation, in its strictest sense, refers to the maintenance of living herds of domestic animals mostly under the original environmental conditions.
This paper will only discuss the methods and the problems we have to face when preserving the populations of living farm animals in situ.
2. Comparison of the efficacy of various preservation methods
It is very difficult to compare the effectiveness of the ex situ and in situ methods because of the diversity of conditions.
It is obvious that the unchanged state of genetic material can be best obtained by cryogenic storage. Over many centuries, apart from technical and human mistakes, only the background radiation can have some unknown effect (Polge, 1981). In short-term surveys one cannot verify damage, but in the long run it would be a great mistake to neglect this factor of uncertainty.
In contrast to the efficacy of cryogenic methods, it is nearly impossible to breed many generations of animal herds without changing gene structure. The most important reasons are as follows:
the number of animals is usually limited, with the possibility of genetic drift,
the normal sex ratio used in domestic animals requires selection every year,
the primitive domestic herds live mostly in harsh conditions and here selection by nature is also very effective, even against our wish.
Thus, cryogenic storage is advantageous first of all when deep frozen embryos are stored. If there is only deep frozen semen one can restore the breed in the future only by upgrading. The upgrading procedure over 5 generations results virtually in the original breed or strain, but even then there are still about 3% of foreign genes.
However, in some countries there are circumstances which prevent the introduction of cryogenic storage of genetic material. At present there are still some domestic animal species, the semen or embryos of which cannot yet be stored in deep frozen form without lethal damage or essential loss.
Another theoretical danger to restoring a cryogenically stored breed or population is that over a very long period, a considerable evolution or change of bacteria or other pathogens cannot be ruled out. Livestock can adapt to the small changes from one generation to the next, but this would be quite impossible for the cryogenically stored animals over a period of, say, many hundred years.
There are some advantages to in situ preservation compared to the ex situ storage. One of the most important aspects is the opportunity for permanent observation which is desirable for several reasons:
to improve characterisation of different breeds of domestic animals and then store
the data in data banks;
to detect and, if necessary, eliminate genetic defects;
to provide aesthetic pleasure for future human generations at the sight of living herds of unusual and pleasant-looking animals;
to reconstruct “original” populations from those contaminated by other breeds.
Many authors believe that the cryogenic methods are not as expensive as preservation by managing living herds (Brem et al, 1982; Beilharz, 1983; Bodó et al., 1984, etc). But comparison merely of the costs is not adequate because cryogenic storage involves only costs, but the breeding of living herds produces some product as well. It is only the net income or the deficit which can be included in such calculations (Smith, 1982). The level of financial productivity of the herds involved in preservation program can change year by year. It is a great danger that on the basis of one year's negative results somebody makes a decision to liquidate a herd which cannot later be restored.
3. Which populations of farm animals should be preserved
There are two reasons for which populations deserve to be preserved: (a) the endangered status and (b) genetic value.
Populations which are not endangered can survive without genetic drift provided numbers are large enough. The possible genetic loss in high-producing populations due to intensive selection is not discussed in this paper. The endangered status of animal breeds can be determined by the size of breeding stock which can be expressed by the number of breeding females and sex ratio, or by the effective population size. In the literature there are many estimates of the minimum size of populations required and on the classification of their status (e.g. Maijala, 1974; Alderson, 1981; Crawford, 1981; Campo and Orozco, 1982; Maijala, 1982; Beilharz, 1983; Pirchner, 1983; Bodó et al., 1984; Thornback, 1984; Perret, 1985; Dohy, 1988). Instead of citing the various numbers only, the common factors, which seem to be increasingly accepted, are summarised here.
Normal status implies that the population is not in danger of extinction, can reproduce without genetic loss and there are no visible changes in population size.
Vulnerable status means that some disadvantageous effects endanger the existence of the population and some precautionary measures must be taken into consideration to prevent the further decrease of the population.
Insecure status of a population means that the number of breeding animals is decreasing and in future years the problems will be increased.
Endangered status implies that a breed is in danger of extinction, because its effective population size is inadequate to prevent genetic loss in future generations. An increase of the degree of inbreeding is inevitable and threatens the vitality of animals and there is a real danger of loss either spontaneously (e.g. disease) or due to negligence by man (Bodó et al., 1984). In this case, the methods of preservation must be enacted to save the population in question.
Critical status is an extension of the endangered status and indicates that the population is close to extinction (Bodóet al., 1984). Then the first action must be to increase the population size. In this status, the genetic variability is often already reduced so that the population in question cannot be considered the same as the ancient breed (Bodó et al., 1984).
Table 1 gives some practical estimates (not experimentally proven) on the number of farm animals involved in the various statuses of vulnerability.
Table 1: Vulnerability of uniparous populations.
|Estimated effective average population size|
|Status||No. of breeding females||5:1||10:1||30:1 sex ratio||50:1||1000:1|
|Normal||>10 000||33 333||18 181||6 201||3 921||195|
|Insecure||5–10 000||5 000||2 727||930||588||30|
Beyond these figures one has to consider the trends in population size.
The multiplication of multiparous species is easier and quicker, it decreases the degree of the danger of extinction but from the genetic point of view the same effective population size is needed.
3.2 Genetic value
The genetic merit of a population from the preservation aspect can be divided as follows:
|complementarity (Bodó et al., 1984)||(g)|
(a) The endangered breeds are not usually high-performance populations. Their performance may be remarkable only under harsh conditions and therefore must not be compared with high-performance breeds in intensive production. There are also some products which have lower value in modern times (e.g. animal draught power in developed countries) but these traits should not be neglected either (Nagarcenkar, 1983).
(b) Adaptability to the local environment - a most valuable trait in indigenous breeds. Animals can be adaptive to local climatic conditions, to the nutrition available in that region, and to the management system under which they are kept. The habits and demands of local human populations can also be considered as an important factor of environment to which the farm animals should be adapted (e.g. Mpwapwa cattle in Tanzania; Katyega, 1987).
(c) Resistance against some pathological agents (infectious and parasitic diseases) is one of the most important merits of a breed or strain to be preserved (e.g. trypanosoma-tolerant cattle; Trail, 1983).
(d) Other traits, for example the screw horns of Racka sheep in Hungary (Bodó, 1985) or some ethological traits (e.g. the seaweed eating sheep; Alderson, 1981).
(e) In general, a population is not worth preserving unless it is pure (Bodó et al., 1984). The concept is, however, disputable and sometimes ill-defined. Essentially it implies that the population should be free from the influence of other populations. However, purity should not imply a homogenous breed - a great deal of variability exists within primitive populations.
(f) In preservation, mostly separate populations are involved (exception: gene pool). According to present knowledge, the heterosis effect depends on the genetic distance between the populations crossed. Therefore it is advantageous when a population to be preserved satisfies the criteria of being distinct. There is no value in preserving animals from a 'breed' which, though it may have a distinct name, has the same genetic structure as another breed (Hodges, 1985).
The basis for this distinction can be: origin, history, location, morphology, biochemical and immunogenetic markers. It is not merely the presence or absence of some characteristics, but sometimes the frequency of their occurrence which should be considered.
(g) In modern time the complementarity of breeds makes possible the excellent use of some animal populations in even very sophisticated cross-breeding systems. The favourable combination of genes cannot be accurately predicted, therefore only experiments can clarify the value of a population in this respect (e.g. the Hungarian Grey cattle breed has given the same results as Herefords in crossbreeding aimed at producing beef (Bodó and Réti, 1987).
Theoretically, all breeds, strains or lines should be preserved because we cannot know the future requirements for our farm animals (Lauvergne, 1981). Thus, the limitating factor is the cost of maintenance. Therefore if necessary a selection should be made between breeds or lines to be preserved on the basis of the criteria considered above.
4. The role of selection in preservation
Selection has a great role in the breeding of domestic animals, because it serves the improvement of livestock and its production. Various methods are recommended for the developing countries where the commonly used solutions of the developed countries cannot be applied. Thus, more and more, the open nucleus system is recommended instead of progeny testing schemes (Buvanendran, 1984; Hodges, 1988). This method can be harmonised within the conservation of genetic resources as well (see 8.1).
In the preserved herds and flocks, however, the situation is not the same. The purpose of preservation is the maintenance of the present stock without genetic change. Selection aims at improvement, i.e. the advantageous genetic change in the population. It is really a difficult question to decide whether selection and preservation can be harmonised or whether they are absolutely opposed.
D. Simon (1982) grouped the objectives of selection in conservation as follows:
to maintain the valuable genes against selection limits;
maintenance for future requirements;
use of livestock in less favourable production conditions.
Of these three the first concerns, predominantly, the high-producing populations and the second and third refer to the herds which can be involved in preservation programmes.
Because of the normal sex ratio used in the in situ herd keeping, the selection of the males is inevitable even in preservation. In addition, it would not be reasonable to cull breeding females too frequently because that would increase the rate of changing of generations. This is not favourable when we want to minimise genetic change.
The most important rules of selection in preservation are as follows:
In order to maintain the unchanged genetic structure of the population it is very important to avoid the impact of famous and excellent males. Therefore the males should be changed relatively frequently and more males should be used than in normal conditions.
One breeder's taste affects the whole population, if there are many smallholders' stocks, the impact of each owner on his own stock cannot be excluded. This can even be advantageous because it can maintain the genetic variability. If the population size is too small (critical status) the spontaneous variety of breeders' tastes is not enough, it is necessary that somebody should take care of all the traits and changes of the population.
When the number of breeding animals is fixed and cannot be increased, a possible method is to replace every female with her daughter and male with his sons as far as possible. This solution is not as easy as it appears.
Not a useful method in preservation is the use of sire's dam system, i.e. to select only the best females in order to give sires. It is better when the dams of future sires are always changed.
When the population is big enough (vulnerable status or better), the selection for divergence can also be used. For instance, in one sub-population, large body size is the goal of selection and in another the small size, etc. This method is admissible only when it fits the traditional practice in the given population.
When blood group data and data on other polymorphisms are available it is important to maintain their variability. This is a method to prevent genetic drift but the effectiveness of this method should not be exaggerated, because only a part of the chromosomes are marked by blood group loci and beside these marker genes the other part of the chromosomes may not be the same (effect of crossing-over). In preservation, however, it is recommended to maintain the rare factors and to control the frequency when it is possible.
Compared to blood polymorphisms the qualitative or Mendalian traits also have importance. An example is the colour of the horn of Hungarian Grey Cattle. The breeding goal was, during past centuries, the white horn with black points. Some animals, however, with dark grey-greenish horns still exist. The frequency of these animals should be maintained within the population.
All these Mendelian traits can be used, but not one exclusively. Priorities must be excluded. It is important in this respect to note that the unicolour breeds have often been bred for only 100–200 years, but older populations with a wide variety of colours can be more valuable concerning their other traits.
Performance can also be an aspect of selection when it has some relationship to fitness, i.e. the biological value of animals. This is one of the most important aspects. The biological value is the expression of the adaptation to given (harsh) conditions and of the resistance against harmful agents which also live in the environment. The parameters expressing adaptation or resistance are performance records at the same time (first of all, fertility, reproduction, mortality and, in a broader sense, the growth rate within the given conditions as well). Heterozygous animals may have a certain superiority in performance and therefore even biological value cannot be an absolute criterion.
Longevity, which expresses and summarises the complex of traits, is itself a useful and valuable trait. It is not advantageous in modern selection systems, where the short generation interval is favourable, but in preservation models it can be used.
We can hope that, in practice, an equilibrium will be established between selection effect and genetic regression and that genetic change will be negligible, similar to the slow development of the breeds in the ancient centuries. An absolutely unchanged genetic structure is unattainable, therefore a combination of preservation of living herds with cryogenic methods is suggested.
5. Importance of variation within a breed involved in preservation
The normal philosophy of breeders is to adjust their animals' production to modern requirements and to make their stock as homogeneous as possible by the improvement of both genetics and environment. In recent decades domestic animal populations changed rapidly and the direction of the recent development has been towards international uniformity.
For example, the overall tendency is to increase the body size of beef cattle. In the United States such breeds as Charolais, Simmental and Hereford seem to be more and more uniform, differing only in colour. No breeders' association wants to run the risk of losing in the competition of breeds. Therefore the ancient size, conformation and type of the animals became rare.
Just after World War II, the heavy warm-blooded German Horse breeds like Hannoverian, Holstein, Oldenburg, etc, were excellent draught horses adapted to the needs of agriculture. When the demand for animal power dramatically decreased, the German breeders responded to the new challenge by using Thoroughbred and Trakehner stallions and now the German breeds are excellent sport horses. The characteristics of these breeds has changed basically, but the old names are preserved.
In the dairy world, the “Holsteinisation” can be observed everywhere (Cunningham, 1981) and even in Switzerland the influence of the dairy character of Holstein Friesian cattle on purebred Simmental can be seen.
When preserving any domestic animal population, we must not be content with the maintenance of the names or the reputation of some groups of breeders, but require the preservation of genes and valuable traits (i.e. the original type, size, conformation, performance, resistance and adaptability of animals (Bodó, 1987a,b)) for the future of mankind.
6. Purification, reconstruction, resuscitation of valuable populations to be preserved
The elimination of foreign genes or characteristics from a population “contaminated” by another breed is possible only by selection of living herds or flocks and therefore this problem belongs also the in situ preservation.
If an ancient breed has been influenced by another breed, preservation is possible in three ways:
by cryogenic methods - but this only postpones the problem of coping with the “contamination”;
by maintenance of the present gene structure in a gene pool. This is possible, but the value of such a population is not so high because of the influence from other, often highly producing, breeds (but it is a method of preserving genes);
by special selection, which can be called “purification” in this case.
To guarantee the preservation of such a population we should be convinced that it does not carry more than 20 per cent of foreign blood (Alderson, 1981). However, the precise determination of this percentage may be very difficult. If the population in question has valuable traits, purification can result in a good population which has merit enough to be preserved. When the foreign influence is too great, a new breed name should be given in order to be authentic.
Thus, the purification is essentially a selection procedure. However, the culling of animals, carriers of foreign genes, is very dangerous when the population size is small. Therefore, with the population in critical status the first step is to increase the population size. Selection is then carried out by culling the animals with markings or characters of another breed or breeds. During this selection an attempt should be made not to decrease the genetic variability in other traits and to maintain the value of the population in question. The selection of males should be emphasised.
An example of a breed where purification was attempted is the Cikta sheep breed in Hungary (Bodó et al., 1984). This is a native sheep of Germany introduced to Hungary by settlers in the 17th century. The breed became nearly extinct in Germany and the Hungarian population was contaminated with Merino. The reconstruction started about 20 years ago with 100 ewes and 5–7 rams. Now the comparison of German and Hungarian reconstructions is very interesting because the difference was so small that both can be considered to be authentic. Only if frozen embryos or semen are available is the resuscitation of an extinct breed or strain possible.
The resuscitation of such a breed or strain by crossing several populations is unacceptable, it can result in the creation of a new breed and not in the reconstruction of the extinct one. A well known example is the unsuccessful resuscitation of the ancient wild cattle.
7. Problem of inbreeding in preserved populations
For breeds or lines of numerically small size, inbreeding is always an important, inevitable though sometimes exaggerated phenomenon. It is so, because preserving of the valuable genetic material starts often at the last moment, when the number of animals is very small.
7.1 Damage caused by inbreeding
Inbreeding in small size flocks can diminish variation in the characteristics of qualitative inheritance, the most spectacular of which is the colour. In spite of the fact that selected domestic animal breeds are often unicoloured, it is important to prevent the further diminishing of colour variation.
More important are the defects caused by major genes. The frequency of harmful genes can increase and more and more genetic defects appear (lack of hair, lack of tail, atresia ani, shortened legs, etc). These are obvious signs of inbreeding. The elimination of carriers depends on the type of inheritance and even inbreeding itself can be considered as a good method for discovering the hidden genetic defects.
The situation is certainly more dangerous, but not so spectacular, if the signs of inbreeding appear in quantitative traits. These characteristics are: low fertility rate, parturition difficulties, increased mortality, decrease of mothering ability of dams, lack of growth, lack of fitness, etc. These problems appear slowly and it is not easy to discover them, because of the considerable influence of environment and human factor.
In an investigation in the Hungarian Grey cattle the correlation between Wright's coefficient and reproductive ability of the cows was only r=0.134, arising from a non-significant difference of 4–5 per cent of fertility between inbred and non-inbred cows (in favour of the non-inbred group) (Bodó et al, 1982).
7.2 The degree of inbreeding
The usual estimate of the degree of inbreeding is the use of Wright's coefficient, when pedigree data are available. However, the simple average of these figures cannot characterize the situation of the inbreeding of a population because it is possible that not all the inbred animals have the same common ancestor. Therefore, when using the coefficient of Wright for characterization of the inbreeding of a population, the number of common ancestors on which inbreeding is made, should also be given.
Without pedigree data, which is often the case in preservation, the frequency of blood polymorphisms can be used for information on the degree of inbreeding (Bodó et al., 1982).
7.3 Mating systems (inbreeding avoidance)
In preserved small populations one of the most important aims in mating is to avoid inbreeding.
Basically, there are two methods: (a) rotating mating system in a random unit, and (b) rotating of mating between smaller sub-populations of the whole population. A study of Yamada and Kimura (1984) has shown that both the probability of fixation of rare genes and the chances of extinction of the population are greater with the sub-population system, contrary to the view in an earlier paper (Yamada, 1981).
Beyond the theoretical problems, the best in practice is to use these two systems in combination. It is possible to establish a national rotation model and to keep some herds as inbred lines. Sometimes it runs automatically in certain small private farms. Though inbreeding will help to bring genetic defects to the surface, in small populations the danger caused by inbreeding is really the more important aspect.
Blood groups are in some cases also useful for preparing mating plans. If pedigree data are not available or uncertain, mating based on blood group alleles makes possible to create progeny heterozygous at least at the marker loci of 12–14 chromosomes (which may change by crossing-over).
There are some theoretically possible mating methods for maintaining the genetic equilibrium from generation to generation, e.g. the 1:1 sex ratio, but this is either impractical or too expensive. Another idea is to select the sires - according to an ethological argument - by allowing the males to fight (bulls, bucks, stallions, cocks, etc) in order to copy natural selection.
However, such solutions never existed in domestic animal breeding, where the equilibrium was produced by a primitive selection process and the effects of the environment.
In the case of preservation, it is better if necessary to mate sisters and brothers rather than parents and offspring, although the resulting inbreeding coefficient is the same, in order to equalise the genetic contribution from the two parent “lines”.
Thus, the recommendation for the mating system in preservation is to use the rotational system for the small populations in critical status and then to increase the number of animals and to create sub-populations which after some generations can be crossed within the population being preserved. For the division of a breed into sublines, a good example can be found in the history of the Lipizza horse breed in the Danube countries (Bodó and Pataki, 1984).
The use of AI when and where it is possible, facilitates the avoidance of inbreeding. In most cases it is technically impossible to run an exclusive AI system, but the deep frozen semen of the males is suitable for creating new lines or to avoid the threat of degeneration.
Finally, the best arrangement to avoid inbreeding is the increase of the number of animals to be preserved.
7.3.1 Feral populations
An extreme solution of a mating system for in situ preservation is to create a feral population. Such flocks and herds are valuable because they represent often a more primitive stage of domestication and they are modified only by natural selection and drift, plus any involuntary, accidental human intervention. A substantial number of such feral populations exist across the world (Table 2). In 1976, a seminar was organised in New Zealand on the possible value of feral mammals. An unsuccessful attempt to create new feral stock of sheep is referred later (see 8.3). The comparison of situation, behaviour, performance, growth etc, of these populations with domesticated ones affords possibilities not only to animal science but also to the development of practical preservation methods.
Table 2: Number of feral populations of the world 1.
|Australia/ New Zealand||South America||North America||Asia||Europe||Total|
1 After Rudge (1986)
8. Special problems in preservation of major domestic species
Cattle are used for milk, meat and draught, singly or in combination. From the aspect of preservation, the management of beef cattle is the easiest. The costs per capita are lower, the technology is simpler and it needs less labour. In the Americas several thousand animals are kept in big farms and controlled by a few cowboys, in European large-scale farms the economic unit is 200–250 beef cattle, guarded by two men. On small farms the size of a family herd is 10–100 cows depending on the size of the farm and other activities of the farm. In general, in beef production the management is extensive and so the environment can affect the livestock through natural selection. If meat is the only product, industrial crossing and intensive fattening can be combined in the programme in order to decrease the unprofitability of preserving old, less productive breeds. In this case, the purity of breeding stock, using purebred bulls, is very important.
The technology of dairy production is more complicated and more expensive. If the cows of a primitive breed are milked the equipment and labour required is nearly as expensive as that for the high producing cows.
The breeds involved in preservation are mostly mixed, dual purpose breeds. True in situ preservation with milking is expensive. To keep such populations in beef herds without milking affords one solution. Theoretically, however, it is not perfect, because in such changed conditions other traits can develop in the herd, due to natural selection.
If these populations cannot remain in original dairy situations the best solution is for the greatest proportion of the bulls (or all) to be selected in milked nucleus populations, and to be used for the beef herd as well.
Nowadays, the draught power of cattle plays an important role in developing countries but has no value in the developed world. With an unpredictable future, draught properties must not be neglected. In the regions where animal power is no longer used, the training and testing of the bulls is desirable (Nagarcenkar, 1983), although perhaps difficult to achieve because of a shortage of labour.
Inbreeding can be used for the detection and elimination of genetic defects.
The cryogenic methods are well developed for cattle, therefore the use of deep frozen genetic material in living herds is relatively easy. Special facilities (working enclosures, etc) are necessary when using AI and so two men can manage 200–250 cows.
The use of vasectomised teasier bulls is advantageous for easier detection of the cows in heat and the permanent demonstration of the males for the public. Disadvantages include the same dangers of accident as for entire bulls and the possible transfer of infection. Experiences with Hungarian Grey cattle show that oxen can also help to detect females in heat.
This species serves primarily transport and agricultural work. In the developed world, the requirement for sports horses has increased and the influence of Thoroughbreds can be seen. In other places the ancient Mongolian and Arabian horse have wide impact. The strains and populations without this influence are highly valuable for preservation (heavy draught horses, some old strains and separate populations).
In the horse species, the adaptability and willingness for work is one of the most important objectives for preservation. Therefore it is reasonable that some work, trial or test should be included in the in situ preservation programme.
Some horse populations can also be more easily preserved by involving them in meat production. This may be the case with the “cold-blood” heavy draught horse breeds. However, without the use of draught power the degeneration of important psychological traits is a possibility. (A similar phenomenon exist in shepherd's dog breeds when they are used only as pets.) Maintaining horse populations in this way is possible only in limited regions.
Tourism provides a good opportunity for maintaining special horse breeds, even asses and breeding of mules. One has to mention the Przewalski horse which is considered as the living ancestor of the domestic horse species. The reconstruction of wild livestock out of the animals coming from zoos is a very interesting activity of several institutions and deserves support. That is also an aspect of in situ preservation.
The maintenance cost per sheep is not as high as that of cattle or the horse. For this reason, the in situ conservation is easier and cheaper, and may be suggested whenever possible.
The products of the sheep (wool, mutton, fur, milk and various cheeses) make for easier commercialisation. Sometimes the selling of the products from indigenous breeds can be combined with folk art. It is the best solution, when the manufacturing and marketing also belong to the sheep breeders, so the products can remain exclusive and profit remains at home (Pflaum, 1989).
In general, the rate of twinning is higher in sheep than in cattle. There are also some highly prolific primitive breeds. These can be used in modern crossbreeding systems, e.g. Romanov ewes served by Suffolk rams or, more complicated, Romanov × Merino ewes mated to a good terminal breed or line. Ewes of native sheep breeds appear to give very good results when mated to well-muscled lines. Such special lines can be improved to maximise their effect for the autochtonous breeds in question. Such a cross-breeding programme, when many farmers and experts are interested in a previously neglected breed, is always favourable to the preservation of the original population. However, the danger of crossing the whole breed without also maintaining a purebred population should be avoided.
Reconstruction of small size breeds is possible, and a programme for the detection of genetic defect can be run as well.
Often, the situation arises where private smallholders keep sheep belonging to a valuable breed in need of preservation, but the breeders do not want to breed the population any more. In this case the animals can be gathered in an experimental farm. A shepherd can keep a flock of 250 animals or more.
The wild ancestors and feral populations of sheep are also valuable. The creation of new feral population is also a possible idea for the sake of preservation, but the environmental conditions are very important, e.g. an unsuccessful trial was made by Hungarian Racka breeders. The males and females of the breed adapted well and quickly to the wild conditions even in winter, but the territory was not big enough and the defensive instinct of animals was not developed for defending the newborn lambs against predators and other damage.
In poultry breeding the genetic problems of preservation can be relatively easily solved in experimental farms in little groups or cages. The best, scientifically based example for the preservation of living animals is perhaps the maintenance of control stocks in the poultry industry. This solution, however, can lead to a contra-selection, or lack of selection, for the characteristics which are important in primitive environment.
Many breeds and the genetic variation of poultry in general depend on the activity of hobby breeders. It is the size, the plume colour and patterns which subdivide these breeds. However, there are a lot of other traits which are neglected in modern times, e.g. the natural hatch which is very important in native conditions. In courtyards of smallholders in the Middle Ages, the poultry stock was multi-coloured and without hatching it could not survive. For this reason, it is very important that a good brood hen should not be culled for small egg production. Beside chickens, other species like duck, goose, turkey, guinea-fowl, etc, should not be neglected.
In the field of poultry breeding, the large international firms control the direction of genetics and they have the financial power. The small producers can maintain genetic resources. The integration of their activities is very important perhaps with more financial support from the big firms in the future.
Where physical work has been replaced by machine power, the human population needs more protein and less lard. Therefore two breeds, the Large White and the Landrace, seem to dominate the world production and also the hybrid breeding programmes.
Maintenance of the valuable ancient populations is difficult because of low meat production and excess fat at the same time. Many native breeds show a small litter size. There are, however, some special populations, e.g. some Chinese pig breeds, which have an extremely high litter size.
The maintenance of a stock of primitive swine costs nearly the same as a high productive modern breed, and the profit is low. The solution of this problem would be to adopt a more primitive and cheap management of swine in European and American countries, where such old management systems are nearly forgotten. It involves yearly one litter in the most favourable season when housing is not necessary and grazing (oak forests, etc) is possible.
Crossbreeding, using males from good meat producer breeds and females from a prolific native breed, is also possible; however, the organization of such a programme is not easy.
The wild ancestor of domestic pig is a living common species which is not threatened by extinction. The crossing with the domestic pig is possible and it often happens. The piglets born from such crossing are not very valuable animals from the point of view of production, because of low growth rate, but can be considered as a special product.
9. Environment as an essential element of in situ preservation
If the population size is not too small, the impact of any artificial selection can be balanced by the “natural selection” through the environment. If the environmental effects are not counterbalanced by man, the population can retain its resistance and adaptation - its most important asset. Theoretically, the loss of some genes or biochemical factors is, of course, possible, but the genetic structure of the population can remain well entrenched in its environment.
There are also some arguable elements, the most important of which is nutrition. In most cases, there are no incentives to change the primitive feeding of animals because of the lack of financial resources. But in some situations - mostly in developed countries - intensive feeding is possible. If this affects only the final products (fattening), and it is not the basis for selection, then no effect is caused to the genetic equilibrium. When, however, the best parents are preferred on the basis of their intensively fattened progeny it should be considered as a modern breed improvement programme and not preservation any more. The maintenance of a local feeding system and of nutritive plants is obligatory because this is an important element of adaptation.
Traditional housing is sometimes also advantageous and economic. However, the local domestic animal populations adapted to the extreme conditions (e.g. nomadic or transhumance systems) are the most valuable for preservation. Sometimes it is not easy to safeguard the traditional conditions, because people do not want to live in such a situation. This human dilemma is very difficult to overcome.
Health control is also a not negligible aspect in preservation policy and raises a lot of questions. If we believe that these ancient breeds are resistant, prophylaxis should not be introduced. Theoretically, this is reasonable, but it is dangerous for several reasons:
some infectious diseases can destroy the whole stock in question, especially when the stock is small;
there is the danger of infecting the human population in some cases;
there is a permanent danger of infecting other modern high-producing populations and wild animal stocks by carriers of pathogenic agents.
The problem is not the same with different diseases, e.g. rinderpest is a dangerous disease which threatens the existence of cattle stock and there are good results in international prevention (JP-15). It seems not reasonable to develop populations resistant to this disease. However, some indigenous sheep breeds are becoming increasingly resistant to the infection of sheep pox (Szent-Iványi, 1984).
One could observe that the primitive Hungarian Grey cattle suffered less and the mortality was much lower during an infection of foot-and-mouth disease, compared to an improved breed (Simmental).
In spite of the theoretical possibility of the improvement of genetic disease resistance to various infections in indigenous breeds, it is impossible to develop such programmes for the reasons listed. Therefore, general veterinary rules apply to preserved livestock. There is, however, an exception. When, in the case of an infection, a slaughter policy were the official and common health solution for the eradication of the disease in question, it must not be allowed in the case of a valuable, unique breed or strain. Then another solution should be found for the preservation of these irreplaceable animals. The details of such exceptional solutions are not the topic of this paper, but it should be decided on the basis of the scientific results, the official regulations, and the local conditions. For the sake of safety it is advisable to establish more than one herd or flock for preserved animals, analogous to the cryogenic storage of genetic material.
10. Organisational aspects of preservation
Without a person who takes the responsibility for the population involved in preservation, good results cannot be attained. The requirements from this person are:
to be honourable and accepted by the breeders and the administration;
to be familiar with the breed or population in question - both its history and the present situation;
to be in good and permanent contact with the breeders, and to control their activity;
to keep or make the herd books or any other records on the animals and lead the extension activity;
to be familiar with preservation policy and to give advice and teach the preservation policy to the breeders;
to be in good contact with other organizations like the Ministry, local governmental organisations, breeders' association, International Association, FAO, gene banks and data banks;
to take part in distribution of financial support if it exists;
to work alone or within the framework of an association or other organisation;
to be responsible for all the data which could be given to the data bank;
to be an enthusiastic person.
The responsible person can be one of the breeders, a researcher, a professor, an administrator or, for that matter, anybody capable of undertaking this work.
The basic problem of preservation is that the maintenance of the animals is not profitable, and therefore the population needs support in order to prevent the extinction. A preserved population is only for the benefit of humanity, so the community is responsible for compensation for loss of commercial profit (Crawford, 1981; Momm, 1987). Such support is the duty of the society because the activity serves its future and therefore it can be carried out by the government (e.g. France) or society directly (e.g. UK).
This support has to make the profit modestly equivalent to the other possible uses of land in the given region. It is not easy to determine the correct amount. The danger caused by over-support is as bad as the consequences of under-support. The problem is made even more difficult by the fact that the appropriate amount of support changes with local monetary and market situations, therefore sometimes the amount of support should be changed annually.
In return for this financial support the breeders of the preserved animals should maintain their stock and respect the rules of preservation, to make their records available and - if possible or necessary - to show the animals to the public.
Tourism is a very suitable possibility to supplement the small income of the breeders of primitive breeds. Special products are also very useful in this respect (e.g. Beaufort cheese of Tarentaise cattle; Pflaum, 1989). The form of the support payment is also very important and may be based on the following:
a certain sum of money per breeder
the number of animals involved in preservation
the number of preserved females
the number of progeny born
the number of progeny weaned
a sum per sire used
free use of sires or AI
the assured selling of the products for adequate prices
organising the processing of the products and assured market for them
for increasing the herd size
In general, it seems that one of the best solutions is when the basis for the payment is the number of weaned progeny because it encourages reproduction.
In order to adjust the support to the actual situation these problems can be decided only on the spot, and must be viewed yearly. On the other hand, the breeder must be sure that the financial support assures him a modest profit for a long time.
Publicity in the in situ preservation of domestic animals is as important as it is in the protection of monuments or wildlife. On one hand society must understand the value of preserved populations and, on the other, the breeders of preserved populations can learn the value of their animals from the interest of the public. Sometimes this interest is as important as the financial support.
The theory and the practice of preservation must be included in the subjects taught at the agricultural and veterinary high schools and universities alongside the other methods of selection and improvement of domestic livestock.
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Elizabeth L. Henson 1
1 Cotswold Farm Park, Guiting Power, Cheltenham, Gloucestershire, England
The importance and need for the conservation of domestic animal genetic resources in the form of breeds and isolated populations has been well documented and is familiar to everyone at this conference. The primary aims of such conservation measures are perceived to be:
the conservation of unique and endangered populations as a genetic resource for future livestock breeders and biotechnologists;
the conservation of historically important, culturally interesting and visually unusual and attractive populations for education, tourism and leisure; and
the conservation of non-selected populations for research, or as a control population for comparison with others.
Breeds or populations become rare or endangered because they cannot compete with modern commercial production breeds or hybrids under the current management systems and in the current economic conditions. They may have advantages in alternative management systems and are often landraces adapted to local environmental conditions. It is generally accepted that any unique and endangered population should be considered as a candidate for conservation even if an immediate use cannot be imagined for its known genetic components. The two principal methods available for the conservation of such populations are cryogenic stores of frozen embryos and semen and live animal programmes.
2. The principal methods of conservation
2.1 The cryogenic option
This paper's primary aim is to consider live animal conservation. However, there are a number of features of cryogenic storage which should be taken into account when looking at the options available.
Cryogenic storage involves the statistical sampling of a population to identify and select donor animals. These animals have semen, ova or embryos collected for long-term storage in liquid nitrogen. The obvious advantage is that all the material which is successfully collected and frozen is permanently saved and, barring any accidents with the storage system, will be available in exactly the same condition at any time in the future. The disadvantages of this technique may be divided into four sections: technical, informational, cultural and economic.
Technical limitations: Frozen gamete technology is not well developed in all species, e.g. pigs and horses, and is not available at all in some domestic species, e.g. elephants and members of the camel family. There are also physiological differences between breeds within species, in their response to embryo manipulation and the use of AI. This has already proved to be a problem for rare breed cattle embryo collection and freezing in the UK, suggesting considerable potential problems in more extensive management situations and in other species.
Cryogenic storage introduces a level of selection and genetic drift resulting from differences in: accessibility to herds because of their physical location and ownership; the behaviour of the animals and ease of management; and the response of the collected tissue to freezing and thawing techniques. All of these variables may change from population to population and between strains within populations. These variables may introduce a level of genetic drift and cannot necessarily be counteracted by appropriate statistical sampling.
Informational limitations: Frozen gametes and embryos will not be of genetic value unless the populations from which they came have been fully characterized and described under a range of environmental conditions, prior to the removal or replacement of the living stocks. Full characterization of rare populations is necessary in order to ensure that the frozen material is identifiable and thus accessible for use.
Cultural limitations: Many rare breeds have played an important role in the history and development of their indigenous areas. Conserving such populations only in frozen stores makes them inaccessible to people as a source of cultural and historical interest, for education or research. Photographs, descriptions, wool samples and even video, cannot achieve the experience of direct interaction with living examples of a population.
Economic limitations: The initial costs of frozen semen conservation programmes are relatively small in most species. However, semen alone can only allow for recreation of a population by gradual upgrading on an existing population of females. Embryo collection and freezing is far more expensive than semen collection. It requires that the females be taken out of normal breeding production for an extended period. It requires a much higher level of technical expertise than semen collection and success rates for collection and freezing appear to vary between females, far more than they do between males.
Although semen collection has been popular in a number of countries, the widespread use of embryo banks has not been taken up. Embryo banks were found to be prohibitively expensive as a means of breed conservation, in a feasibility study carried out by the Rare Breeds Survival Trust in Britain in the late 1970s.
Frozen collections are expensive to initiate but once they have been established, they have a small cost associated with equipment maintenance, liquid nitrogen supply and data bank information. Frozen stores have potential for income through the sale of surplus stock of semen and embryos.
2.2 Live animal conservation
The use of live animal conservation programmes may be essential in situations where cryogenic storage is not yet technically possible and may overcome some of the other problems associated with the cryogenic storage. Live animal programmes used in conjunction with working stores of frozen semen have been found to be most successful in a number of programmes in Europe and North America.
In order to best consider the effectiveness of live animal conservation programmes, we should look at the aims of these programmes and the inherent advantages and disadvantages of the systems. The major objectives, scientific conservation of genetic combinations, conservation of breeds for cultural and historical interest, conservation for research, and the use of rare breeds in economic settings. The practical programmes in operation obviously cross these major divisions.
2.2.1 Scientific conservation of genetic combinations
In order to maintain genetic variation within live populations over a long period of time, the effective population size (Ne) must be relatively large (see Figure 1).
In addition to the direct ratio of males and females in the population, the age structure and reproductive success of individuals influence the calculation of the effective population size (Ne). This results in a very large real number of animals needed to sustain a population with little or no genetic drift (Ne is nearly always substantially smaller than the actual population size, N). Extensive use of AI technology and frozen semen stores, where possible, in conjunction with large female populations may therefore be a beneficial strategy.
Figure 1: Loss of
genetic diversity (as measured by heterozygosity) due to random drift for various
effective population sizes (Nc).
Source: Foose, T. and Seal, U.S. (1981). A species survival plan for Siberian Tiger in North America. AAZPA, Wheeling, West Virginia.
In effect, the live animal conservation programmes which exist, seek to maximize Ne within their financial limits. These financial limits therefore greatly affect the programme's successful outcome.
Besides the genetic drift associated with small population sizes, the major scientific problem with live animal conservation programmes is selection. The initial drift in live animals' programmes is small since theoretically the entire population may be included in the programme. However, over time, genetic drift is enhanced by inevitable selection on the part of the livestock keepers. This may be a particular problem in populations which have characteristics perceived by the livestock keepers to be a ‘fault’. For example, keepers of multi-horned breeds of sheep in both the UK and North America are actively selecting against a congenital condition which affects the functioning of the upper eyelid. It has been shown that this condition is closely linked to the multi-horn characteristic and has been present in the multi-horn breeds for a considerable length of time. Similarly, there is an attempt to eradicate a chromosomal translocation believed to be associated with fertility problems in the British White Cattle of the UK and Australia.
There is also a tendency with live animal populations to select to ‘improve’ characteristics thus making the breed more economically viable. There is a case for such directional selection when it results in a population being slightly changed, but achieving numerical stability, because it has found a new role in the market.
There will also be drift in live populations even under conditions of minimal selection. This is due to better survival of those animals with adaptation to changed management, better feeding and veterinary care and other environmental factors. Once again, one could argue that such change is essential if breeds and populations are to have any real use in the future. Frozen populations which have not been allowed to adapt over time to constantly mutating animal diseases and a changing background of environmental conditions will be unlikely to thrive when revived after sustained periods of storage in liquid nitrogen. Thus some level of adaptive change may be both necessary and desirable. However, the use of frozen semen banks as a back-up to live animal conservation programmes could help to ensure that such changes are limited and not irreversible in order to prevent the total or dramatic loss of specific genetic variation.
2.2.2 Conservation of breeds for cultural and historical interest
The majority of live animal conservation programmes has approached rare breed conservation with the principal aim of preserving rare breeds as part of the national cultural and historical heritage. These programmes have then been adapted to ensure the optimal strategy for the conservation of genetic variation within breeds.
The organizational structures involved in conservation programmes for cultural and historic use are very varied indeed and fall into three major groups: national or government funded projects, non-government projects and private organizations.
22.214.171.124 National or government funded projects
In a number of countries the establishment of national or state parks as conservation areas has been associated with the conservation of national or regional rare breeds. The most famous, and probably most effective of these is the Hungarian programme at Hortobagy National Park in Eastern Hungary. Here, herds of Hungarian Grey Steppe Cattle, Mangalica Pigs, Racka Sheep, Water Buffalo and poultry are carefully conserved in a large-scale government programme. This programme seeks to maintain the ancient grazing lands known as the Puszta, along with its wildlife, rich botanical diversity, cultural heritage and traditional livestock breeds. The programme has its own state funded budget through the National Park authority and has very close links with university personnel who control the breeding programmes and use the animals in extensive research.
In other areas of Europe and North America, the inclusion of rare breeds into national or regional parks has been rather less structured and more incidental. However, in most cases the commitment to the rare breeds involved has increased over time and the survival of the populations has been enhanced by the actions of the authorities involved.
In France, the ecologically important area of the Carmargue in the Rhone delta is maintained as a national park whose brief also includes the conservation of the ancient semi-feral populations of Carmargue ponies and cattle. These animals are maintained on a feral system with minimal management, recording or intervention in the breeding cycle.
Similar projects also exist in the state parks of Florida in the USA where the Florida Pineywoods or Cracker Cattle have been associated with the ecology of the area for a very long period and where their conservation has been incorporated as an integral part of the Park's aims in conjunction with research support from the state university. This idea has also been used in other European countries with feral or semi-feral populations. For example, the feral herds of Pajuna Cattle and Galician Ponies are maintained, respectively, in the National Park of Andalusia in Spain, and the Peneda Geres National Park in the extreme north-west of Portugal.
The conservation of Rove goats in France has taken the management of a rare breed in conjunction with a natural area a stage further and incorporated these rare goats into the management and conservation of the associated forests of the Parc Naturel Regional du Luberon in Provence. The plan is to use the goats in place of expensive mechanical machinery to keep the fire breaks free from scrub.
The Government of Greece has extended its preservation of cultural and historical artifacts and buildings to incorporate a project to ensure the survival of the ponies of Skyros Island. The ancestors of these small, but strong and hardy ponies were the war horses of the Greek Empire and appear in relief in the Elgin marbles. This small national project recognizes the cultural and historical importance of this breed and seeks to conserve the population as part of Greece's national heritage. Tourists are invited to visit the project and could potentially supply much of the funding needed for its maintenance.
126.96.36.199 Non-government projects
Some of the most successful conservation programmes for live populations have been carried out by national non-governmental organisations. In some cases, these are organizations dedicated to the conservation of rare breeds but in others, rare breed conservation has been a convenient and complementary adjunct to their work in environmental or historical conservation and education.
The Nature Conservancy Council in Britain, for example, is involved in the conservation of natural wildlife habitats. It has, however, used a number of rare breeds of sheep to graze coastal areas and other grassland meadows for which flora need to be grazed in order to maintain botanical equilibrium, and where there are rare butterflies and other insects which need grazed plants to complete their own life cycles. In particular, the small, light-weight primitive breeds, like the Soay sheep, have proved to be very useful in areas of fragile soil or high soil erosion and where sheep with low management requirements are an advantage.
Similarly, the Dutch State Forestry Service, which is responsible for conservation, has recently imported Scottish Highland cattle to graze their nature reserves established to conserve Dutch wildlife. These areas would have originally been grazed by Aurochs which are now extinct, and later by extensive and hardy semi-feral breeds which, due to the extreme specialization of Dutch agriculture, are also now extinct. Luckily, comparable breeds do still exist in Britain and the importation of hardy, Scottish Highland cattle into Holland has been successful. The cattle graze the herbage to the correct level, do not need winter housing or intensive management, and still produce a harvest of lean meat.
From a historical viewpoint, the National Trust in the UK, which is concerned with the preservation of historical monuments and buildings, has begun to use correct ‘period’ breeds in the fields around many of its properties to add authenticity, assist in the educational work, and help to ensure the survival of these breeds.
Finally, Utah State University has been involved in helping the Navajo Indians to rescue all that is left of their ancient breed of sheep. This population was light-boned with clean legs and face and was well adapted to the extremes of heat and cold on the Navajo reservation. The sheep survived with little or no management and produced a very characteristic fleece with a dense, fine undercoat with long, coarse hair growing through it. The fleece was used by the Indians to produce beautiful rugs, now considered to be very valuable in fashionable New York shops. They are of great cultural importance to the Navajo people and have a good financial potential to a community with an otherwise very low income. Sadly, however, the sheep which produced the fleeces needed for rug making have all but disappeared after many years of ‘upgrading’ to improve meat production. Utah State University has been active in helping to locate the last pockets of the breed, move rams between groups, multiply numbers and supply the weaving families with the wool they need. Ultimately, the plan is to replenish the flocks of the weaving families with true Navajo Churro sheep.
188.8.131.52 Private organizations
There are two categories of organization conserving rare breeds whose priority is conservation for cultural, historical and educational reasons. These are the living history farms and farm parks.
Living history farms: In many countries, the 19th century ideas of museums and libraries filled with static exhibits and information are being replaced. There is a growing interest in ‘living’ history, and interactive information technology. Our children learn computer keyboard skills almost before they learn to write. They expect interaction, individual attention and variety in their learning environment. Many children are remote from primary food production and many children from urban centres have little or no opportunity to interact with animals. The conservation of rare breeds in live animal situations can help in a number of these areas. In the USA, the interactive experience of ‘Living History’ with historical settings brought back to life with costumed interpreters who practice their skills in front of the public, has proved very popular and effective. This is now being extended to include ‘period’ livestock. In museums, like Colonial Williamsberg in Virginia and Plymouth Plantation in Massachusetts, the issues of livestock breeding, agricultural change and conservation can all be addressed using live animals as teaching tools.
As a general rule these centres act primarily to draw attention to the changing face of agriculture and to the loss of historical breeds. They do not generally have the resources or expertise to indulge in large-scale breeding programmes.
Farm parks: The concept of a Farm Park was initiated in the UK and is best characterized by the Cotswold Farm Park which was the first to open to the public in 1970. It is a privately owned collection of British rare breeds in active breeding units. Small groups of each breed are then exhibited to the public in an attractive setting, and visitors pay a fee to enter the exhibition area. The primary goal of the owners of the Park was originally to be a breeding centre. Public access was perceived as a means of funding the project and was promoted via the historical, cultural and aesthetic interest of the breeds. This concept has been very successful. The centre has never received outside financial support and yet has been able to maintain populations of over 300 rare breed ewes, 100 cattle, 30 pigs, 50 goats and 15 equines, entirely supported by the 100 000 visitors to the Park each season. However, it has had, in conjunction with the other farm parks which now exist, an even more important consequence for the whole rare breed conservation movement in Britain. Farm Parks have formed a focus for the press and television and are popular visitor centres for school groups, holiday makers and tourists. This media interest has enabled public awareness of the idea of rare breed conservation to reach a high level. This in turn was instrumental in the early success of the Rare Breeds Survival Trust (REST) in the mid-1970s and in the development of private ownership of rare breeds which has been the key to the overall success of the UK programme.
2.2.3 Conservation for research
The use of rare breeds in research has been sporadic and largely ineffective in ensuring the survival of many breeds. There are a umber of examples where university or research institutes have inadvertently slaughtered the last group of animals in a breed, once they have finished their research, including the last herd of Lincolnshire Curley Coat pigs in Britain, and the last large flock of Navajo Churro sheep in the USA. There are obvious exceptions to this trend. Universities have been able to identify immediate uses for some breeds, for example, the prolific Finnish Landrace sheep.
In terms of maintaining live populations of rare breeds, universities and research institutes have not been generally effective. There are exceptions, the University of Reading in the UK housed part of the London Zoo ‘Living Gene Bank’ for a number of years in the 1960s but was unable to continue due to funding restrictions. The bank was then transferred to the private collection which became the Cotswold Farm Park in 1970. Florida and Louisiana State Universities have both been involved in the research of the Gulf Coast Native sheep which are well adapted to the heat and humidity of the region and are resistant to the predominant gut parasites. Over the past 50 years, the sheep industry in the south-eastern states has all but disappeared due to economic and market changes. Today, almost all that remains of the Gulf Coast sheep population is held in the two university flocks.
Other organisations involved in research that have used rare breeds in some small pilot schemes are those concerned with human/animal interaction. Research in social psychology and medical research has revealed the importance of the interaction of people with animals. In particular, work with mentally disturbed patients has suggested social and behavioural benefits. In a number of cases rare breeds are being incorporated into state prisons and institutes for the mentally disturbed and mentally ill. Suffolk Borstal Prison Farm for young offenders in the UK, has made the interaction between individual boys and Suffolk Punch horses a major feature of their rehabilitation programme. Green Chimneys Farm School in New York has also included a rare breeds programme with their residential centre for maladjusted juveniles. Stocken Prison Farm in the UK has a herd of White Park cattle for which the inmates are responsible. All of these programmes help to establish stable relationships between inmates and the animals with which they work, a sense of achievement and pride, and enables the inmates to learn new skills while helping to conserve a breed.
Few commercial companies are able to consider rare breeds in research programmes. The possible use of rare breeds to biotechnology and genetic engineering companies, although theoretically valid, are still some way off technically and require good characterization of breeds.
However, many veterinary and medical research and production companies require the use of farm animal hosts. One US drug research company has entered into a contract with a US rare cattle breeder, to supply them with cattle blood for research. The owner is able to maintain the herd at the low level of veterinary input which the company requires and the company is able to provide the owner with financial support. Although only a pilot scheme, this is a possible source of funding for more substantial rare breed conservation programmes in the future.
2.2.4 Rare breeds in an economic setting
The major area for concern when considering live animal conservation programmes is that of cost. Economic aspects of conservation have been addressed most fully by private companies, independent organizations, and in projects involving large numbers of farmers with small flocks or herds.
184.108.40.206 Private organizations
Private organizations involved in rare breed conservation fall into four major categories. First are the livestock breeding companies which need genetic variation as their primary resource. These are mostly poultry and pig improvement companies. Second are organizations whose primary aim is rare breed conservation and which use tourism and education to help fund their work. These are the Farm Parks and have been described above. Third are conservation or historical organizations involved in tourism and education which have included rare breeds in their programmes to help in the interpretation of their historical site, and assist with rare breed conservation efforts as an offshoot. These are the living history farms described above. The fourth are companies whose work is quite separate from rare breed conservation, but which have found a role or use for rare breeds.
Breeding companies: In the most developed of the livestock industries, and particularly in the poultry industry, there are a few breeding companies who hold the bulk of the genetic material which make up the production stocks. Three primary breeders currently provide most of the world's turkey poults and one has over half the world's market. There are only nine world class primary breeders of chicken broilers and nine primary breeders of egg layers supplying most of the industrial sector throughout the world. It may be further speculated that many of the grandparent lines of these companies have identical or similar origin. The result is a high level of genetic uniformity in the industrial stocks world wide.
The industrial poultry companies are dependent upon new genetic variation in order that their improvement programmes continue. Intensive selection is already resulting in a situation where they have homozygous birds with maximum genetic production for the genes at their disposal. The companies are very competitive and do not exchange ideas or genetic stocks, although many have ‘gene banks’. However, they aim to plan their breeding programmes ten years in advance and hope to be self-sufficient in genetic material for that period. Meanwhile, they are continuing to actively seek additional genetic resources outside the company, although as their influence on the industry increases this will be more and more difficult to find.
With the increasing availability of genetic engineering options these companies may wish to consider single gene transfers from landrace stocks where these still survive.
Several commercial swine companies are multinational, supplying an increasing proportion of breeding stock to the industry. They are currently seeking genetic material from around the world and do not appear to hold very large genetic reserves.
Finally, the artificial insemination companies in the cattle industry have the potential to hold very valuable collections simply by saving a sample of each bull collected for AI use. The British Milk Marketing Board (MMB) instituted this system many years ago and does hold a gene bank of AI samples from across all the breeds, including those rare breeds collected by the Rare Breeds Survival Trust Although a relatively simple and cheap method of establishing and maintaining a gene bank, it has not been taken up by many other countries where AI companies are private businesses in competition with one another and where such projects are considered to be untenable and expensive luxuries. This has been particularly the case in the USA where over 50 companies compete for the AI market and where no single company or group of companies has taken responsibility for a gene bank. The semen from bulls for which there is not a current market is simply destroyed.
Non-breeding companies: Promotion of the issues connected with conservation of rare breeds has been brought to the public's notice. This in turn has prompted some companies who use farm animals to consider using rare breeds rather than commercial or cross bred animals. For example, the animal feed company Rumenco has developed a herd of English Longhorn cattle for the farm around their headquarters. They look attractive and give the company an image of caring about conservation and the environment Similarly, companies like Volvo and the National Westminster Bank, have associated themselves with rare breed conservation through sponsorship. Perhaps the most spectacular promotional use of rare breeds is the Budweiser Company's use of Clydesdale horses in the USA. Begun in 1933 at the end of prohibition, this advertising campaign using Clydesdale horses became very popular and successful. However, unlike many other campaigns it became an integral part of the company's image. Budweiser are now leading breeders of Clydesdales and have been very instrumental in the survival of the breed both in the USA, Canada and Britain. This alliance has therefore been successful for both the company involved and the breed with which it chose to associate.
English China Clays have found an essential role for a rare breed in their industry. The company managed to develop grasses that would colonize china clay spoil heaps but the grass species were slow growing and did not develop a strong enough root system to prevent rapid erosion. A suitable grazing animal was needed to strengthen the root structure while not destroying the fragile surface. Primitive Soay sheep were found to be ideal. They are ‘light’ in weight and small enough to not damage the surface soil structure, and had the correct grazing habits to help to establish the grasses and encourage the development of the stable green cover needed for the rehabilitation of the unsightly industrial spoil heaps.
Private conservation organizations: Probably the best known of the non-government funded organizations in the field of rare breed conservation is the Rare Breeds Survival Trust (RBST) in the UK, whose primary activity is as a grassroots network organization for individual breeder members. The RBST seeks and receives financial support from the public, foundations, corporations and companies specifically for the work of rare breed conservation but receives no government funding.
The RBST has become directly involved with ownership and management of some animals including the principal flock of North Ronaldsay (Orkney) sheep. This is a small, naturally short-tailed breed which had adapted over some hundred years to exist on a diet of the seaweed laminaria. In 1970, the entire population was situated outside the sea wall on the beach of the Island of North Ronaldsay in the North Sea. In 1973, a representative of the working party which was later to become the Rare Breeds Survival Trust, purchased the small island of Linga Holm and moved a group of 150 sheep and established a second sanctuary for the breed with the same environmental conditions and food supply as on the parent island. Today, the RBST flock is gathered once a year, the fleeces are shorn and the lambs harvested. There have been a number of research projects carried out on various aspects of the breed's behaviour and physiology. It is hoped that by maintaining this second site, the breed will survive even if a disease outbreak or oil spill threatens one or other of the flocks. There are now a number of trials using North Ronaldsay ewes on other isolated islands, where they are rearing, on a seaweed diet, cross bred lambs with reasonable carcasses.
The RBST also has a large semen bank held in conjunction with the Milk Marketing Board. This incorporates both a long-term store and a working store which enable individual breeders to be involved in cattle breed conservation without needing to own a bull. They encourage the characterization of and research into breeds through universities and organizations like the Meat and Livestock Commission (MLC).
In addition, the RBST is involved in paying grants and subsidies to farmers to assist them in keeping rare breeds and acts as a network organization to coordinate the activities of individual farmers.
Private individuals: The most powerful and stable form of live animal conservation programmes currently in operation, are those which involve large numbers of small privately owned units. This system has two advantages. First, it maintains a very high effective population size (Ne) due to there being a large number of relatively small units each with at least one male. Secondly, it requires a very large number of decisions for significant changes to occur. Thus, selection pressures are likely to be ineffective because they are not generally uniform between units and the programme would fail completely only if individuals were to withdraw their support.
Individual farmers involved in conservation in Britain and the USA fall into three main groups. The first are the traditional farmers who still have ‘old’ breeds because they have not for one reason or another moved on to the new ‘improved’ production strains. The second are modern commercial farmers looking for specialist markets or production systems. Some are interested in developing specialist markets for named meat, cheese or wool products, others in comparing rare breeds with their commercial stock. These are the groups with whom limited breed characterization work has been done. The final group, which constitutes a major part of the UK programme, are the ‘hobby’ fanners who make their living outside agriculture but who have small farms with small flocks or herds to primarily help with conservation and to supply their own meat, milk or wool.
As individual units none of these would be significant. However, in conjunction with one another they can be very effective. The traditional means of combining breeders of the same breed together has been through breed associations and in some cases these are still active.
Breed associations are groups of individual farmers who maintain and produce the same pure breed. They act as a pedigree registration and certification service to their members and as a commercially based breed promotion and marketing service. In normal circumstances, they seek to ‘improve’ their stock by encouraging selective breeding. The combination of breed improvement and breed promotion do therefore appear to be in direct opposition to the concept of the conservation of genetic variation. However, provided every breed has an active association and efforts are made to keep breeds separate they do act in combination to conserve variation.
Breed associations for minor breeds are able to keep breeders in touch with each other; keep and make available pedigree information essential to prevent serious inbreeding; and help to promote the breed. Active associations are very important in ensuring that a breed can survive, but they are dependent upon member contributions, and in the case of small associations are normally member run. It therefore often happens that a very rare breed that really needs a breed association cannot sustain one. In this situation, network organizations, like the RBST in Britain and the American Minor Breeds Conservancy (AMBC) in the USA, can be very effective in providing assistance with basic secretarial, communication and registration services until members are able to sustain their own breed organizations.
In extreme cases where the survival of a breed has been seriously threatened by financial pressure on farmers from more commercially successful alternative breeds, the use of subsidies has been very effective.
In Canada, the regional government of the Province of Quebec has instituted a system of paying a dollar subsidy to farmers rearing purebred Canadienne cattle. Similarly, the RBST pays a headage grant for every purebred Shetland calf born on the Shetland Islands, calculated from the difference between the market value of a purebred calf and a crossbred calf. They also pay a subsidy to the owners of rare breed boars which are siring litters, and give financial help to selected stallion owners in strategic geographical areas, provided their stallions are offered at stud. In addition, there are bull rearing grants and incentives to enable bulls to be collected for AI use.
This system of subsidy has been a direct and effective method. In financial terms, it has also been cost effective. The difference between the production level under good management of the rare breed and that of the replacement is large enough to induce a farmer to change over breeds, but it is not normally large in comparison to the costs of establishing an independent conservation programme.
3. Prospects for the future
The aim of this paper was to review the current programmes of live animal conservation of rare breeds in Europe and North America with respect to their possible application in other parts of the world, and in particular for those areas where there is dramatic agricultural change and therefore potential genetic loss. Not all the experiences and ideas transfer freely from one region to another but many may be applicable in different situations.
Globally, the most endangered breeds and populations are primarily endemic populations which are regionally adapted, but which are under threat due to replacement or ‘upgrading’ by imported ‘exotic’ breeds. The imported stocks or their hybrids produce food for human consumption under improved management and feeding regimes. This often requires imported technology and veterinary medicines which in turn may require foreign currency or aid.
Cryogenic stores may be the only long-term chance of survival of the endangered populations in some areas. However, there may be technical problems associated with populations in rapid decline because their physiology may not yet be adequately understood. Removal of indigenous populations by replacement or dilution also prevents their use as a sensible control, and makes their practical use less likely. On the other hand, available options for live animal conservation may not be easily transferred.
3.1 Live animal conservation programmes
3.1.1 National programmes
Rare breeds may be incorporated into wildlife and nature reserves. However, this is less likely to be successful outside Europe. Within Europe, the indigenous wild grazing animals, the Aurochs, Bison, Prezwalski Horse, Mouflon and Wild Goats have long ago been driven to extinction, other than in tiny pockets or in zoos. It is therefore reasonable, in Europe, to use rare breeds of domestic and in particular feral populations, as the large grazing animals in wildlife reserves. In most of the rest of the world there are still wild species of grazing animals which have survived although in some areas these wildlife species may also be rare. In these areas wild animals will and should be used to fill the grazing niche on wildlife reserves.
3.1.2 Non-government organizations
There is a real case for the involvement of universities in rare breed conservation in all countries, but particularly in areas where there is large-scale upgrading or replacement of breeds under way. In these areas, universities and research institutes should be involved in maintaining purebred populations of indigenous breeds as a control population and for research. Universities involved in medical or veterinary research could also be encouraged to use rare breeds where livestock are needed. For example, the cattle supplying blood for human vaccines could be rare breeds in conservation herds.
3.1.3 Private companies
In poorer nations, the use of public concern to affect the actions of companies will be less effective than in richer ones, because consumers have less financial power. What consumer pressure there is will come from the richer consumer nations and is likely to be directed towards wildlife and ecological conservation if it is directed at conservation at all.
There is also a slim chance that companies involved in mining or heavy industry could be encouraged to use rare breeds in land reclamation programmes or publicity campaigns but realistically they are more likely to use endangered wild species.
Breeding companies based in the richer industrialized countries of the world are most likely to become involved in rare breed conservation. They are likely to take cryogenic samples for use in biotechnology at home. They may then return this genetic material to its original source country in patented new varieties, but they are unlikely to make it freely available, which is the intention of most pure conservation efforts.
The idea of Farm Parks in nations where most people still have close links to the land, seems unlikely to succeed. However, in countries with a tourist industry this is a real possibility. Linked to the idea of a truly living history, it would be possible to incorporate traditional skills, breeds and plant crop varieties in an exhibition alongside a parallel demonstration of the modern techniques, varieties and breeds. It would help visitors to understand the culture of the country they were visiting and support the indigenous agriculture and its breeds. It could also act as a valuable information, training and teaching resource for local people who could see the advantages and disadvantages of the old and new alongside one another.
3.1.4 Individual farmers
The use of individual private flocks and herds coordinated by organizations committed to rare breed conservation offers the most powerful and cost effective means of rare breed conservation. it makes use of the skills and knowledge of farmers familiar with breeds, and keeps those breeds interacting and developing in the same environment to which they are adapted. Financial assistance and incentives can be paid to farmers in a number of ways through cultural, historical or agricultural organizations.
Subsidies can also be paid based on a number of different systems, per capita, male only or production.
Payments made on a per capita system have tended to encourage farmers to overstock their land. It has also been paid regardless of the quality of husbandry and tends to encourage ‘bad’ farmers to keep rare breeds and live off the subsidy while ‘good’ farmers move over to the new breeds and farming systems.
The system used in Britain which pays a subsidy for purebred males of specific blood lines kept at stud, has helped where the level of production of the rare breed is not very much lower than commercial breeds. In this situation, a relatively small financial grant to help with the cost of keeping a male makes up the financial difference between the rare and the commercial replacement breed.
Production linked subsidies, however, seem to be the most controlled and most effective system. In this case, the subsidy is linked to the real production potential of the animals. The amount of the subsidy is determined by evaluating the production under normal management of the rare breed, and comparing it to the potential production of the replacement breed in the same management system. The farmer is then paid a subsidy equivalent to the difference. In using this system it is essential that the farmer continues to farm his animals well in order to make the maximum use of them. This ensures that good farmers will still be attracted to the scheme.
Programmes have been designed to use local farmers in vegetable plant conservation in different parts of the world, and the ideas could be used equally well for farmers involved in livestock programmes. The units do not need to be very large and through production-linked subsidies the income of farmers involved in these programmes should hold the same cultural and social value and the same sense of pride and responsibility as breed replacement and improvement programmes. They should be used as control herds to monitor the advantages of the imported stocks. As control herds, they should have parallel opportunities to improve husbandry where this can be sustained in the long-term economy of the country.
Such conservation projects could be coordinated through independent organizations where this is appropriate, or through universities or state agricultural agencies. It could be internationally, regionally or state funded through internal agencies or aid agencies. Ideally, however, each aid project designed to replace or upgrade indigenous stocks with exotics should have a budget component to establish a control programme to conserve the indigenous strain in the same conditions.
In conclusion, the methods of conserving rare breeds in live animal programmes are very widespread and diverse. Not all of these methods transfer easily to all regions of the world, due largely to competition for resources from the indigenous and endangered wildlife species. However, there is a real opportunity for live animal conservation programmes associated with university research, biomedical and veterinary research and production, and through a system of farmer subsidies in parallel with the introduction of replacement breeds by the aid agencies.
The time when living populations of rare indigenous breeds are no longer needed for genetic conservation has not yet arrived, if indeed it ever does. In the meantime, breeds are best maintained in their own environment, tended by those who know and understand them best. The need to preserve genetic variation in domestic livestock has been recognized for years and it is now even more urgent in a rapidly changing world. Farmers must be fired with enthusiasm to preserve the breeds evolved and shaped by their ancestors but that fire needs monetary fuel. It must be quickly and wisely applied before the fire is extinguished by the need for immediate survival rather than long-term conservation.
Arthur da Silva Mariante 1
1 National Research Centre for Genetic Resources and Biotechnology, CENARGEN/EMBRAPA, Caixa Postal 10.2372 - Brasilia - DF - BRAZIL.
Many Latin American countries are concerned with the conservation of livestock populations belonging to the “local” breeds (genetic groups originated with animals introduced by the settlers). These populations have been submitted to a long process of natural selection, having thus acquired adaptative and/or productive traits for the diverse ecological conditions found in the continent. Most of these populations are in an advanced state of genetic dilution and/ or in danger of extinction, as is the case for some breeds of cattle of the Criollo type.
The establishment of programmes for preservation of livestock breeds in danger of extinction are a must in order to avoid the imminent disappearance of many of them. Some Latin American countries have already created their programmes, such as the Brazilian National Programme for Animal Genetic Resources; the Criollo Project developed by CIAT and British Tropical Agricultural Mission in Bolivia; the Criollo Yacumeño Programme, also in Bolivia; the Argentine Criollo cattle project in Argentina, the Colombian Programme, the Calabozo Project in Venezuela, among others.
Unfortunately, it is not easy to get information about what is being done on this subject in each one of the Latin American countries. This paper is not a complete report about programmes of preservation of animal genetic resources, but presents some of the most important of them.
2.1 Programme of preservation of Criollo cattle of INTA
The criollo cattle, for more than three centuries the only cattle responsible for the production of milk, beef, and draft in all Latin America, were replaced firstly by the European breeds and, more recently, by zebu and its crosses. In Argentina, the situation was not different, and the numbers of criollo cattle were quickly being reduced when, in the 1960s the Instituto Nacional de Tecnologia Agropecuaria (INTA) in Leales, Tucuman, decided to start an evaluation programme.
At the beginning of the evaluation programme, the criollo were used as a control population, compared to other breeds and to crossbreds. Surprisingly, the results showed that the criollo were the most productive breed.
In a second phase, the reproductive efficiency of the criollo cattle were evaluated in different environmental conditions, from the ones found in Leales: La Rioja, Santiago del Estero and Jujuy, with positive results in all situations (Holgado, 1989).
Many other studies are being done with the objective of evaluating the Argentine criollo cattle: consumption, forage utilization, meat quality, resistance to external parasites and diseases, blood typing, and crossbreeding programmes with European and zebu breeds.
At present, the population is about 150 000 head of criollo cattle, even though it is difficult to estimate precisely the numbers, as well as its degree of racial purity.
In Argentina there are 27 known herds, with 18 being privately owned, 5 belonging to INTA, and the other 4 to government institutions of different provinces. The oldest and biggest herd belongs to INTA Leales, and has a total of 160 females over two years of age, and 17 bulls. This herd meets the needs of different research projects which aim at evaluating the criollo cattle.
The recent creation of the Criollo Breeders Association will positively influence the conservation, diffusion and improvement of this important genetic material, that may act as a source of genetic variability to confront present and future challenges for animal improvement.
Bolivia has two different programmes for conservation of criollo cattle: one in the region of Santa Cruz de la Sierra, which includes criollo bulls from different Latin American countries, and the other in the Beni region (Criollo Yacumeño).
3.1 CIAT/BM Criollo Project
A programme utilizing criollo cattle from Bolivia and from other Latin American countries was established by the Centro de Investigation Agricola Tropical (CIAT) in conjunction with the British Agricultural Tropical Mission (BM). The objective of this programme is to utilize criollo cattle for dual purpose production in the lowlands of Bolivia.
According to Wilkins et al. (1979) the productivity of cattle with more than 75% blood of the European dairy breeds in Bolivia, was lower because of higher calf mortality and lower fertility. This result led to the need to maintain a population of tropical dairy cattle to produce bulls for systematic crossbreeding programmes with European dairy breeds, and thus, this project was set up, with the following stages (Wilkins and Rojas, 1989):
Diagnosis of problems in the livestock industry;
Investigation of the potential role of the genotype;
Economic evaluation of the proposed breeding programme;
Involvement of the livestock industry; and
Although the original purpose of the project was to provide criollo bulls for use in crossbreeding, the results have shown that the breed has a commercial role in its pure form.
The results found by Wilkins and Rojas (1989), show that if concentrate foods are available to supplement the improved pastures, crossbred cattle can be recommended for milk production. However, if concentrates are not available, the advantages of the crossbreds over the selected tropical dairy cattle are considerably reduced.
Some production parameters of criollo cattle compared to Brown Swiss and F1 criollo/ Brown Swiss are shown in Table 1. The criollo herd is still in a multiplication phase, and in May 1989, there were 174 females over two years of age. The herd will reach full size in 1992/93, after which it will be possible to select intensively the females.
Table 1: Production parameters of females of Criollo, Brown Swiss and F1 Criollo/Brown Swiss females at CIAT - Bolivia.
|at first calving||364||362||361|
|Age first calving (days)||897||1085||929|
|First lact. yield (kg)||968||1687||1668|
|Lactation length (days)||272||301||291|
|First calv. interval (days)||415||533||403|
|Calf mortality (%)||5||18||10|
Source: Wilkins and Rojas (1989).
3.2 The Criollo Yacumeño
The Criollo Yacumeño Project is conducted at the Espiritu Ranch, located in the Beni region, close to the Yacuna river. The Beni is a flood plain with a humid tropical climate in the Amazon Basin.
In 1961, Bernardo Bauer, the owner of the Espiritu Ranch and the researcher Dieter Plasse designed a breeding programme in which they intended to crisscross criollo and zebu cattle. In order to start this programme, they needed good quality criollo bulls and, for this reason, they selected an elite herd from an original herd of 6000 cows. In 1964, they had a 364 cow-herd, and decided to name them Criollo Yacumeño. Today the herd has about 850 females and the goal is to reach 1000 cows (Bauer et al., 1989). The main objective of this programme was to create a criollo breed that, in the environmental conditions of the Beni, could present good reproduction and production traits, to be used in crossbreeding programmes with zebu cattle, that would produce crossbreds with higher yields than the paternal breeds. The following steps were necessary to establish this programme:
Identification of each animal;
Reproduction and production records of each animal;
Evaluation of performance tests;
Selection of the superior individuals, according to the less production tests; and
Culling of the animals that did not present the phenotypical characteristics established for the breed, such as coat colour and hair type.
Results of 20 years show a pregnancy rate of 82%, calving rate of 78% and weaning rate of 74% with a weaning weight of 160 kg. The productivity of the Criollo Yacumeño is slightly inferior to the productivity of zebu cattle, however, there is a trend to level out. The crossbreds present better production rates than the Criollo Yacumeño and zebu cattle.
According to Bauer et al. (1989), it is necessary to prove economically that the Criollo Yacumeño present similar or better productivity than zebu cattle in tropical climate environments similar to the Beni region. Only then, will it be possible to promote the creation of new criollo herds. Until now, only an insignificant number of bulls are sold for crossbreeding programmes. Breeders have to organize their ranches better in order to be able to do so.
De Alba (1987) stated that the Criollo Yacumeño is “the most promising source of improved germplasm for all lowland beef production in the tropics”.
4.1 National Research Programme for Animal Genetic Resources
Aware of the importance of the conservation of animal genetic resources, the Brazilian Agricultural Research Corporation (EMBRAPA) through the National Research Centre for Genetic Resources and Biotechnology (CENARGEN) started a programme in 1981 including cattle, and later buffaloes, pigs, sheep, horses and donkeys. The conservation of goats is being conducted by EMBRAPA-CNPC (National Research Centre for Goats), located in Sobral, state of Ceará. Table 2 shows a summary of the identification of genetic groups in danger of extinction in Brazil.
The programme established by EMBRAPA-CENARGEN includes the following steps:
Identification of the populations in an advanced state of genetic dilution, involving census and geographic distribution;
Characterization of germplasm: blood typing analysis and cytogenetic characterization;
Productive potential evaluation through phenotypic and genetic parameters.
The conservation is being done either in situ (breeding nuclei) or ex situ (cryopreservation of semen and embryos).
As can be seen in Table II, the Brazilian National Programme for Animal Genetic Resources includes projects with 6 species co-ordinated by CENARGEN, besides projects with goats and woolless sheep, co-ordinated by CNPC.
After the first three forementioned steps of the programme had been established, for research projects all over the country, it was decided to start an ex situ programme, in order to avoid genetic dilution and irreplaceable gene losses of the valuable ”local” breeds. A semen and embryo bank was then established, which until now stores frozen semen and embryos of cattle.
Techniques in cryopreservation, thawing and embryo transfer to recipient cows are wholly successful. Micro-manipulation of embryos has permitted the production of identical twins from a single embryo. Hemi-embryos (embryo halves) can be frozen and stored for a long time, thus allowing evaluation of zootechnical traits of an individual or its progeny, while maintaining a copy in the gene bank. Genotype by environment interactions can be evaluated over time, by allowing identical twins to develop in different years.
More recently, CENARGEN started a cryopreservation programme with horses and goats. The technology utilized with cattle has been adapted to horses successfully, and in 1988, a foal originated from a hemi-embryo was produced, as well as foals from frozen embryos. The cryopreservation of goats however, has just started, and there are no results available yet.
Many research results of the species and/or breeds included in this programme are discussed in another article by the same author in this publication.
5.1 Colombian Programme
Colombia is one of the Latin American countries that present one of the biggest varieties of criollo breeds. Romosinuano, San Martinero, Blanco Orejinegro and Costeño con Cuernos are the most important of them. The Costeño con cuernos, however, is almost extinct. These cattle were kept by the Ministry of Agriculture at Valledupar and were later transferred to Monteria, where more qualified personnel could take charge of them. The other three have already formed Breed Organizations and are maintained in government owned Experimental Stations:
Romosinuano - there is a preserved herd at Monteria, Sinu, but the programme was not very successful in improving performance or expanding numbers. One herd is kept at an Experimental station of the OAS in Turrialba, Costa Rica. This herd has 150 cows and is being used to promote the formation of several satellite herds of private breeders and the Costa Rican Ministry of Agriculture.
San Martinero - the Colombian government maintains preserved herds at Iraca, La Libertad and Carimágua, in the Llanos.
Blanco Orejinegro - a nucleus of this breed is maintained by the Instituto Colombiano Agropecuario at the El Nus Experimental Station in Antioquia.
Even though Colombia has all these breeds, it seems that a co-ordination programme with the same objectives for all criollo breeds is missing in order to better preserve and evaluate this genetic material.
Table 2: Identification of genetic groups in danger of extinction - Brazil.
|Size||Miscigenation degree||Geographic distribution||Situation||Nuclei|
|Crioula Lanada||In course||300–400||Low||SC/RS||Stable||Offic/Priv.|
|Nordestino||In course||>10000||Low||MA/PI/RN/CE/ PE/PA/AL/BA/MG||Decreas.||Offic/Priv.|
Source: Mariante et al. (1988)
1 Survey in course, present estimate value for population size.
6.1 Venezuelan Programme - The Calabozo Project
Even though this project is specifically a crossbreeding programme, it can also be considered as conservation because it includes the Criollo as purebreds as well as crossbreds. According to Plasse (1989), because of the danger that the Criollo might be eradicated, several experimental stations and producers have investigated their potential for crossbreeding.
The Calabozo Project started in 1965, in Calabozo Experimental Station, located in the Guarico State, Central Llanos of Venezuela. The breed combinations that included Criollo cattle were the following:
Purebred Criollo Limonero
Brahman x Criollo Limonero
Santa Gertrudis × Criollo Limonero
Criollo Limonero × Criollo Llanero
Brahman x Criollo Llanero
The foundation Criollo cows had different origins: the Criollo Limonero had been utilized in the Milking criollo project in Maracay and later culled for reasons that did not interfer in their meat production, while the Criollo Llanero were bought in many regions of the Venezuelan Llanos (Plasse, 1981)
A twenty year rotational crossbreeding programme has been completed, but the data have not yet been analyzed. It has been noticed in this project, as well as in many other projects carried out in Tropical Latin America, that where moderate quality savanna exists and adequate management and sanitary programmes can be organized, 50% of zebu genes and 50% of Bos taurus (Criollo and/or European) will probably constitute the optimum proportion to guarantee maximum productivity in the population. Experimental upgrading of Criollos to zebus has confirmed what has happened historically in all tropical cattle populations in Latin America: after the generation of F1 cows and ¾ calves, the tremendous crossbred advantage was gradually lost and the available data indicate that the present grade zebu population may not be any more productive than the original Criollos (Plasse, 1989). These conclusions show once more the importance of the conservation of criollo cattle.
The fast growing science of Biotechnology may lead to newer techniques of gene preservation. DNA recombinant techniques, embryo manipulation, cloning of desirable genes from the same or other breed populations may one day become commonplace. We do believe that all doubts that may persist about the importance of the conservation of animal genetic resources will disappear when we think about the future use of just one especial technique: the formation of transgenic animals. The Gene Banks will play an important role when the desirable genes, responsible for characteristics such as adaptation, heat tolerance and resistance to parasites, will be utilized in the formation of such animals. And then, only the countries which have started serious conservation programmes will be able to form the transgenic animals that will meet their specific needs. It will be too late for some countries to start. The time is now, before most of the “local” breeds disappear due to systematic crossbreeding programmes with exotic breeds.
Bauer, B, Zamora, R. and Galdo, E. (1989). Criollo Yacumeño. In: Conservación y Mejoramiento del Ganado Bovino Criollo. Santa Cruz de la Sierra.
de Alba, J. (1987). Criollo cattle of Latin America. FAO Anim. Prod. and Health Paper. No. 66.19–41.
Holgado, L. (1989). El Bovino Criollo en la Republica Argentina. In: Conservación y Mejoramiento del Ganado Criollo. Santa Cruz de la Sierra.
Mariante, A. da S., Trovo, J. B. de F. and Primo, A. T. (1988). Conservaçao de germoplasma animal no Brasil. In: Encontro sobre Recursos Genéticos. FCAV. Jaboticabal, pp. 148–161.
Plasse, D. (1981). El uso del ganado criollo en programas de cruzamiento para la produccion de carne en America Latina. In: Recursos Geneticos Animates en America Latina. FAO, Roma. pp. 77 – 107
Plasse, D. (1989). Results from crossbreeding Bos Taurus and Bos indicus in Tropical Latin America. In: Utilization of Animal Genetic Resources in Latin America, International Symposium, Ribeirao Preto. pp. 163–181.
Wilkins, J. V., Pereyra, G., Ali, A. and Ayala, S. (1979). Milk production in the tropical lowlands of Bolivia. Wld. Anim. Rev. (FAO). 32: 25–32.
Wilkins, J. V. and Roja, F. (1989). Criollo cattle utilization for dairy production in Bolivia. In: Utilization of Animal Genetic Resources in Latin America international Symposium, Ribeirao Preto, 1989. Anais. Ribeirao Preto, pp. 221–230.