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CHAPTER 7
CONSERVATION OF ANIMAL GENETIC RESOURCES IN BULGARIA

by

Tz. Hinkovski and A. Alexiev

Scientific and Productive Corporation
for Cattle and Sheep, Suhodolska 30
Sofia
and
The Buffalo Institute, Shumen, Bulgaria

Summary

The intensification of animal production in the last decades has "brought about decreasing number of the breeds used a basic means for production. In Bulgaria an attempt is being made, by direct subsidies to breeders, to conserve all breeds in danger of extinction.

  1. Conservation of the aboriginal breeds

The system used for their conservation is described.

  1. Conservation of some cultural breeds threatened with extinction.

This problem is relatively new for Bulgaria and is probably a specific one. During these last years a fundamental breed reorganization in the sphere of cattle breeding has been carried out. The dual-purpose cattle breeds are replaced by specialized milk breeds. A real danger arose that the existing breeds would disappear completely. It was decided that they must be conserved like a gene fund with a fixed size for each breed. In each one of these populations an intensive purebred selection will be carried out relying on their own bull production and on the importation of semen from the breeds which have taken part in the creation of these populations. A bank of frozen semen is used as a gene reserve.

7.1 Introduction

The intensification of the output of animal production in Bulgaria during the last decades has led to a decrease in the number of breeds used as the basis for production. Very often the preference for one breed over another is based on comparatively perfunctory knowledge of the complex qualities which characterize the advantages and disadvantages of the respective breeds. Breeds having a lower total productivity, or not suitable for keeping in the conditions of the industrial complexes, were quickly replaced by more productive and specialized breeds and by crossbreds. Together with the loss of genes caused by the extinction of breeds, we have some loss of genes as a result of the intensive selection that has been practised within breeds. This process, characteristic of all countries with developed animal breeding, is very clearly apparent in the countries having large socialistic farms in which the animals are under industrial conditions of expliotation.

Some improved breeds with a lower productivity have been replaced during the last two decades by more highly productive and more specialized breeds but the real danger was created by the complete extinction of many indigenous breeds of cattle, sheep, pigs, poultry and horses.

This loss of genetic material occurred as a result of the changed market demand and of the changed conditions in which the animals are maintained, and will continue. But in the very long term some of this material may be very useful and necessary for new conditions which may arise in the future. That is why the problem of conservation of the rare and endangered breeds is bothering many specialists. Different countries will use different methods for solving this problem.

In the present report the necessity for the conservation of genetic resources in animal breeding is not considered. This problem has been discussed during recent years at many congresses and meetings. We think that today we all have realized the danger from the loss of valuable genetic material and the specialists are fully convinced of the need to conserve for future generations all animal breeds which have been created and still have not been destroyed.

The words "valuable breeds" are avoided in this report because the importance and the value of a breed change over the years with the change of people's needs and with increase of knowledge in the sphere of biology and in particular of genetics.

The following basic problems have to be solved in order to develop a complete system for the conservation of a given breed threatened with extinction.

1. First of all there is the question of economic incentives for conservation. The reason for the decrease in the population or the extinction of a breed is clearly the lack of economic interest for its maintenance.

Different methods may be used - directly subsidy, increasing the price of a definite specific product from the breed, organizing of special reserves etc.

In Bulgaria this question is decided by a direct subsidy. Annually the National Agricultural-Industrial Union pays the owners of the special conservation breeds definite sums. The funds granted for an animal are equal to the net income from an animal of the most productive breeds in the country. The funds are granted to specially registered herds. Every year for this purpose several million levas are spent from the national budget. Independently, a range of investigations is being made on the use of different breeds in systematic crossbreeding systems. Thus there is provided a possibility for selling breeding animals and also for increasing the economic advantages from maintaining these breeds.

2. Which breeds are conserved in our country? All those threatened with extinction. It is not possible to divide these breeds into "valuable" and "less valuable" because the contemporary judgement may differ from that of future generations.

In general the breeds conserved in Bulgaria may be divided into two groups:

  1. Indigenous breeds created during the course of history and specific for the conditions in Bulgaria. These breeds as a rule have a very low productivity.
  2. Improved breeds, having a comparatively low productivity.

These are the breeds on the basis of which the animal production industry was organized in the past but which are now being replaced by the specialized and highly productive breeds.

7.2 Conservation of the indigenous breeds

7.2.1 Breeds conserved

In Bulgaria a large number of indigenous breeds are conserved. The history of their creation begins from the time of the Thracians. At present the country has 18 indigenous sheep breeds, three cattle breeds, one buffalo breed and four goat breed groups, as listed in Table 6.1. We shall give a short description of only a few of them.

Rhodopi cattle (Bos taurus braohyoeros) were kept in the Thodopi mountains even before the coming of the Thraoians to the Balkan peninsula. It is one of the smallest (in size) breeds in Europe. It uses very well the steep mountain pastures poor in vegetation. The liveweight of the cows reaches 250-300 kg and that of the bulls 400-500 kg. The average milk yield per lactation is about 1250 kg with 4.4% fat. Good results are obtained when it is crossed with the Jersey breed. These crosses have an average milk yield about 2000 kg with 4.7%.

Iskar cattle originated by crossing Bos taurus braohyceros and Bos taurus primigenius. This is a medium-sized animal which is kept along the rivers Iskar, Vit, Osam and Rositza. It is known for its strong and stable constitution, very good working capacity and hardi­ness. The average liveweight of the cows is about 400-450 kg with milk yield per lactation of 2600-2800 kg and 4.4-4.5% fat.

The Native Bulgarian buffalo penetrated into Bulgaria through Byzantium and has been reared for 12 centuries in this country. In the past it was used mainly for work. It is known for its great hardiness and very good ulilization of roughage. The selection for the formation of a milk-type animal began at the beginning of this century. Its milk yield varies from 700 to 1500 kg with fat content about 8%. A record milk yield is recorded of 4OO4 kg with 8.4$ fat in 354 days.

Karakachan sheep. This is the most coarse-wooled sheep in Bulgaria; it appears to be a variety of the Zackel. It is mainly a mountain sheep and is kept mostly in south Bulgaria. The animals are resistant to poor feeding conditions but are of low productivity. These sheep have an average liveweight of 30-33 kg, average fleece weight of 1-2 kg and average milk yield of 40-55 kg. By crossing with the Karakul valuable Astrakhan-type furs can be produced.

7.2.2 Breeding schemes

Creating the economic incentives does not completely solve the problem of the conserv­ation of a given breed. Rinds can be granted only to a limited number of the given breed. In this connection the most important stage is the working out of a system for selection in the breed with a limited number of animals. The main elements of the system worked out for conservation of the indigenous breeds in Bulgaria are as follows:

  1. Sheep

For each breed are formed four flocks with 500 ewes on farms located in regions typical for the breed. The whole system of feeding and maintaining of the animals is preserved but buildings are modernized to a certain extent. In some of the tourist regions these farms are related architecturally with the environment according to special plans. In Bulgaria there are in several regions, reserves with built-up areas, conserved as national museums.

In forming the herds animals typical of the breed were chosen. The question of the nature of selection to be used in the different breeds was a subject of sharp discussion. And especially whether any selection should be done at all in these flocks. The question was decided with a compromise. The purpose of conservation is to attempt to preserve the genetic variation and not to select animals of one type. In three of the herds a system of minimal selection is used and in of of them selection is carried out on the characters for which selection was made in the past.

This question is of great importance in sheep. It is well known that the results from freezing of ram semen are not yet satisfactory. This means that other methods must be sought for conserving of the genetic variation existing in a given breed.

For each flock on formation are chosen 20 typical, unrelated, breeding rams. The ewes and rams are divided into five conventional groups of four rams and 100 ewes each. The mating of the animals is carried out by a system of rotation as shown on the scheme in Figure 7.1. To begin with, for four years animals are mated within groups. After this period we proceed to the rotations shown. After a definite period an exchange of two of the groups between the different herds is foreseen after which the mating will be continued according to the scheme shown. Each of the breeding animals is used for only two seasons. Within the group two offspring from each ram are retained, two from each initial breeding ram are used, or eight rams in each group. Annually 20 ewes are replaced and the proportion between the four related groups is maintained. In the selection of the breeding animals from the three herds, the basic traits are: breed type, vitality and fertility.

In the fourth herd a selection is made according to the characteristic traits of the breed, as was done in the period when the breed was used. In the herd five lines with definite standard are created.

Independent of these four herds associations of the breeders of sheep of a given breed are being formed. The aim is 50-100 small herds (5-10 ewes in each) - the private property of individual cooperative farmers. In the future it is expected that breeding animals from these herds will be used in the four state farms.

About 2000 ewes and 80 unrelated rams are obtained from each breed according to the suggested scheme. This makes it possible to reduce inbreeding to a minimum. With the private ownership of indigenous breeds that reduction will be still greater.

  1. Cattle

Prom each of the three indigenous breeds a few herds are formed, divided into four groups. In each group four groups of unrelated bulls are used. A bank of deep-frozen semen has also been formed. Prom all available bulls about 20,000 doses are stored.

The selection is carried out on the basic traits of selection according to a fixed standard for each breed. Great attention is paid to breed type, fat content and rate of growth at an early age. These are the basic characters on which selection was made in the past. A plan for progeny testing of all available bulls is worked out on the basis of which the final formation of the groups is made. The remaining typical representatives of these breeds are bought up for breeding. In the south of the country special reserves are being formed where the animals are maintained in pasture "complexes". The system of selection used at present is liable to be changed in the future.

  1. Buffaloes

During the last 20 years the Native Bulgarian buffalo has been crossed with the Murrah breed. The newly created buffalo population is reniarkable for its high milk yield and good growth rate. The average laotation milk yield of the adult buffalo cows is 1900-2000 kg with 7.7-7.8% fat. Many buffalo cows have given 2500-3200 kg and the highest yield was 4485 kg.

During recent years the Nili-Ravi breed has been used for crossing. These crossbreds have replaced the native buffalo both in the socialist section as well as in the private sector. This meant that quick measures had to be taken to conserve the native breed. A state herd of 200 buffalo cows has been formed and the formation of two more herds is expected.

During the last two years a method for deep freezing of buffalo semen was successfully developed in Bulgaria. A special station is established in which are concentrated the most valuable buffalo bulls from the newly-created Bulgarian population and the Murrah, Nili-Ravi, Jafarabadi and Surti breeds. Deep-frozen semen from these breeds is stored in the form of straws and pellets. Deep-frozen semen from all available native Bulgarian buffalo bulls is also stored as a gene reserve.

  1. Goats

There are a few aboriginal goat breed groups in the country. for the present the size of these populations is adequate. However replacement by the Saanan breed is occurring very quickly. Therefore conservation measures are necessary. for the present the conserv­ation of one of the aboriginal goat breeds is organized in a scheme which is similar to that for sheep.

7.3 Conservation of some endangered improved breeds

This prolem is relatively new for our country and probably a specific one. In recent years a fundamental breed reorganization has occurred in cattle. The new dual-purpose cattle breeds (Bulgarian Red and Bulgarian Simmental) are being replaced by specialized milk breeds (Holstein-Friesian and its crosses). The fact that there are large farms and selection work is centralized makes it possible for this reorganization to take plaoe very quickly.

A real danger arises that the existing breeds may become extinct. It was decided that they must be conserved like a gene fund with a fixed size for each breed.

In each of these populations an intensive purebred selection will be carried out. For that purpose in addition to breeding our own bulls, we shall rely on imports of the breeds which have taken part in the creation of these populations.

At present there are reserves of deep-frozen semen from a great number of bulls. This stored semen, including semen from all bulls tested during the last 2-3 years, is conserved as a gene reserve.

7.4 Conclusion

Some of the elements of a national programme for the conservation of animal genetic resources are presented here. The different schemes are not perfect. However a good beginning has been made. In the future this programme will change with increase in our knowledge in this field.

FIGURE 7.1

  animal genetic resources
conservation and management

TABLE 7.1

INDIGENOUS BREEDS

CATTLE  
Rodopi
Iskar
Local Grey
 
BUFFALOES  
Native Bulgarian  
SHEEP  
Karakachan Teteven
Rodopi Central Svishtov
Karnobat Breznik
Copper-Red Shumen Daben
Strandja Koprivstenska
Sakarska Panagiurska
Balkan Central Kotel
West Balkan  Starozagorska
Replian Blackheaded Pleven

Conservation des ressources généticnies animales en Bulgarie
Résumé

Avec l'intensification de la production animale au cours de ces dernières décennies, le nombre dea races qui foment 1'assise mème de la production a diminué. Dans beaucoup de pays, un grand nombre des races éleviés dans le passé ont disparu ou sont en voie d'ex­tinction parce qu'elles ont célé' la place à d'autres races supirieures, en dépit du fait qu'elles étalent bien adaptéea au climat local. I1 faut done prendre des mesures efficaces pour conserver les races menacées.

Les auteurs décrivent les éléments d'un programme global de conservation des ressources génétiques animales en Bulgarie. Dans cette étude, ils n'examinent pas le problème du nombre croissant des races très productives et très spécialiées qui ont été créées ces derniers temps, comrae partie intégrante du patrimoine zoogénétique général exietant dans le pays. Us évitent d'utiliser l'expression "race de valeur", car l'importance et la valeur d'une race donnée varient dans le temps, avec 1'évolution des besoins et avec 1'amélioration des con-naissances en biologie et, en particulier, en génétique.

Les problemes fondamentaux à résoudre pour organiser un système complet de conserva­tion d'une race menacéd d'extinction sont les suivants:

  1. En premier lieu, il faut encourager les mesures de conservation par des stimulants économiques. En Bulgarie, une subvention directs est accordée à cet effet. La subvention accordée par animal est égale au revenu net par exemplaiB de la race la plus productive du pays. Les fonds sont accordéd à des troupeaux spécialement enregistrés.
  2. Quelles races sont conserées dans le pays? Toutes les races menacées d'extinction. Selon les auteurs, il est vain de vouloir diviser ces races en "races de valeur" et "races de moindre valeur" parce que les points de comparaison changent avec le temps.

En général, les races animales conservées en Bulgarie sont divisées en deux groupes:

  1. RaceB autochtones peu productives, particuliérement adaptées au milieu local.
  1. Races sélectionnées, ayant une moindre productivité et qui sont raaintenant remplacées par des races plus productives,

Telles sont les races à partir desquelles la production animale a été organisée et qui sont maintenant remplac6es par des races spécialiées plus productives.

I. Conservation des races autochtones

Un grand nombre de races autochtones sont conserveés en Bulgarie. Leur création remont* au temps des tribus thraces. Le pays compte actuellement 18 races autochtones d'ovins, 3 races de bovine, une race de buffle et 4 groupes de races caprines. Seul un petit nombre d'entre elles sont decrites dans oette communication.

Créer des motivations économiques ne résoud pas complétement le probléme de la conservation d'une race donnée. Il est logique de penser que des fonds ne pourront être accordés que pour un nombre déterminé de sujets de la raoe considéréd. Le plus important à cet égard c'est d'établir un systéme de sélection dans cette race, avec un nombre limité d'animaux.

Le système gènèral conyu par les auteurs pour conserver les races autochtones en Bulgarie est dècrit dans cette communication.

II. Conservation de quelques races sélectionnees menacees d'extinction

Il s'agit d'un problème relativement nouveau pour la Bulgarie et il lui est probablement particulier. L'élevage bovin a été réorganisé de fond en comble ces dernières années. Les raoes bovines utilisés à deux fins sont remplacles par des races laitières specialisées. Le danger que les races existantes disparaissent complètement est devnu trèe réel. II a été" décidé de les conserver pour qu'elles servant de réserve de gènes, avec un effectif déterminé pour chaque race.

Dans ohaoune de ces populations, on pratiquera une sélection intensive dans la race, en utilisant leurs propres taureaux et en important du sperme des races correspondantes qui ont contribué à la creation de ces populations.

Une banque de sperme est utiliséé comee réserve de gènes.

Conservación de los recursos en la Bulgaria
Resumen

La intensificación de la producci6n animal en los últimas decenios ha dado lugar a una disminuci6n del número de razas utilizadas corao medio básico de produoci6n. En muchos países han desaparecido, o están en vías de extinción,,gran parte de las razas criadas en el pasado, las cuales, aunque se adaptaban bien a las condiciones climatológicaB locales, han cedido el paso a otras razas superiores. Por oonsiguiente, se requieren medidaa eficaces para conservar las rasas amenazadas.

En el informe, los autores senalan los elementos particulares de un programa general de conservación de los reoursos geneticos animales nacionales de Bulgaria. A este respecto no se eiaminan los problemas originados por el número oada vez mayor de razas altamente produotivas y especializadas, creadas intensivamente en estos últimos tiempos, como parte oonstituyente de los genes animales normalee ezistentes en el país. Los autores evitan el empleo de t<rminos tales como "razas valiosas"4 ya que el valor y la importanoia de una determinada raza oambia durante el ourso de los anos oonforme oambian las variaoiones de las neoesidades de la poblaoión y aumentan los oonooimientos en la esfera biológioa y sobre todo en el campo de la genética.

A continusoitin se senalan los problemas básioos que deben resolverse para el estable-oimiento de un sistema oompleto destinado a la oonservaci&i de una determinada raza amenazada de extincion.

  1. Ante todo, existe el problema de los incentivos económicos de la conservaci6n. En Bulgaria, esta cuestión se resuelve mediante una subvención directa. Los fondos ooncedidos para la explotación de un determinado animal equival«n a los ingresos netos obtenidos oon un animal de la raza mtm productiva del pafs. Los fondos se concede para los hates espeoialmente registrados.
  2. iQue razas se oonservan en el país? Todas las razaa amenazadas de extinci6n. Según los autores, no es posible dividir esas razas en "valiosas" y "menos valiosas", ya que las bases de comparaci6n oambian con el paso del tiempo.

En general, la conservación de las razas animales en Bulgaria se divide en dos grupos:

  1. razas aborfgenes poco productivas — espeofficas de las condiciones locales.
  1. razas de cultivo, de productividad inferior y que se sustituyen actualmente por razas mis productivas.

Estas son las razas en base a las cuales se ha organizado la producción animal y que se sustituyen aotualmente por razas especializadas de mayor produotividad.

I. Conaervacion de razas aborfgenes

En Bulgaria se conserva gran número de razas animales aborfgenes. La historia de su oreación comienza desde el tiempo de las tribus de Tracia. Actualmente, el pafs cuenta oon 18 razas aborf.genes de ganado cvino, tres de ganado vaouno, una raza de bufalos y cuatrc grupos de razas de ganado caprino. En el dooumento se da s61o una desoripoión de algunas de ellas.

La oreaci6n de incentivas económioos no resuelve completamente el problema de la oonser-vaoión de una determinada raza. Es lógioo pensar que se ooncedan fondos únicamente para un número fijo de una determinada rasa. A este respeoto, lo más importante es la elaboraoión de un sistema de selecoión de esta raza con un número limitado de animales.

En general, el sistena de conservación-nawiacifcn. de las rasas aborlgenos de "Bulgaria elaborado por loa autorea eata deaorito en el documento.

II. Conservacion de algunas rasas culturalea amenasadas de extincion

Eate problema ea relativamente nuevo en Bulgaria y ea probablemente de carácter eapeoífioo. Durante eatoa últimoa añosae ha operado una reorganizaci6n fundamental de rasas en la eafera sootecnioa. Las razaa de ganado vacuno de doble flnalldad ae sustituyen por rasas lecheraa especial!sadas. Surgió el peligro real de que laa rasaa exietentea desaparecieran por complete Se decldl6 que debfan conaervarae como un fondo de genea con un tamaño eatablecido para cada rasa.

En cada una de estan poblacionea se realizará una aelección intenalva dentro de la rasa medlante la propia producci6n de machos bovinos y la lmportaclón de dosls de semen de las rasas correapondientes que han tornado parte en la oreación de estas poblaciones.

Se utiliza un banco de dosis de semen como reserva de genes.

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