3.1 Developed Economies
3.2 Developing Economies
Since livestock function as an integral part (and often the dominant part) of farming systems, any impact on the genetic constitution of livestock populations must be considered in the context of these farming systems.
In developed countries (broadly speaking OECD, CIS and Eastern Europe) farming systems have certain common elements. The climate is mostly temperate. Agriculture is generally rainfed. Farming systems are fully market oriented, and often very specialised. The developed countries have nevertheless a higher than proportional share of the breed diversity in the world. This is probably due to the fact that the process of specialisation and intensification of agriculture itself produced an increased number of breed types before the rapid loss of breed diversity set in.
For cattle, sheep and horses, the developed world has approximately 30% of global numbers. It has about the same percentage of world cattle breeds, but closer to 40% of breeds of horses and sheep. For goats and asses these regions have only 6% of global numbers, but approximately 20% and 25% respectively of global breed diversity. Only in pigs, and perhaps in poultry, is the proportion of global numbers higher than the proportion of breeds. In pigs, the developed countries account for about 40% of numbers, but closer to 30% of breed diversity. Of course other important species like buffalo and camelidae are almost unrepresented in the developed countries.
A total of 1,227 breeds of the seven main species have so far been classified in these regions. This is probably close to a complete enumeration. For some 70% of these breeds population data are available, and of these more than one third are at risk according to the criteria of the FAO World Watch List6.
Dairy Production throughout the developed world is now dominated by a single breed, Holstein-Freisian, which accounts for over 60% of dairy cows in Europe and 90% in North America. Many other breeds (for example Fleckvieh, Normande) also exist in large populations. However, as genetic improvement and management systems push milk yield to ever higher levels, the dual purpose (meat & milk) objectives of these breeds fades out and they come under increasing pressure for crossing with or replacement by Holstein. At the other end of the scale, small breeds, which were formerly kept for milk production (Kerry for example) are now not involved in dairying systems.
Within large populations there are two concerns for the future: extreme specialisation and narrowing of the genetic base. A recent study of the structure of US Holsteins7, for example, shows a predicted increase in inbreeding of 0.725% per generation over the period 1990 to 2015. This corresponds to an effective population size of 66.
Beef cattle and sheep are, more than other ruminant species, mostly tied to grassland or forage production systems, often in less favoured areas. Intensification in these systems is less profitable, and therefore the process of economic adjustment has more often been in the form of a gradual increase in herd or flock size. This relative stability has protected genetic diversity to a certain degree. The principal danger from economic adjustment is that production systems in some areas might simply cease for economic reasons.
Horse and ass populations in developed countries declined drastically through the present century as their work function in agriculture and transport was mechanised. This trend has been substantially reversed in the past 20 years as leisure and sporting uses have expanded. This has particularly favoured local breeds.
In poultry, almost the totality of production comes from commercial hybrids. These are crosses between specially selected lines derived from relatively few breeds. Almost all genetic change (about 1% annual gain in egg production, 3% in growth rate) is the product of breeding company programmes. Inbreeding effects are limited to the parental lines used, and do not affect the commercial populations, which are largely hybrids.
For the main species and production systems in the developed world, the process of narrowing the genetic base is likely to continue. For all species, genetic diversity at the breed or strain level is not sustained by commercial production systems, and persists mainly in small local populations, often sustained by special conservation programmes.
The broad pattern is that breed diversity in each species falls into two groups. Relatively few, highly selected, breeds dominate production agriculture. There is cause for some concern about the narrowing of the genetic base even in these large breeds, particularly in the case of dairy cattle, where intense selection and widespread use of artificial insemination have a dramatic effectA13. The second group is the much larger number of breeds which no longer compete effectively in mainstream agriculture. Because of the enthusiasm of breeders and breeders groups, and the expansion of animal keeping for sporting, aesthetic or other reasons, the situation for these breeds has improved in recent years. Awareness of the value of animal diversity is general, and is reflected in official conservation programmes in many countries. The most notable of these is the incorporation of a special supplementary measure on the conservation of local breeds within the European Union Common Agricultural Programme (Regulation 2078/92).
The developing countries account for nearly 2/3 of the worlds livestock. Intensity of production, as measured by average output of meat or milk per animal, is about a quarter of that in the developed countries. It should be recognised, of course, that in many environments these are not the principal economic outputs, and that a more meaningful measure would include such products as work, manure and hides.
Breed diversity is so far very incompletely documented. Approximately 1,500 breeds have been described at some level, while at least 1,000 more are totally undocumented.
Because of the very incomplete nature of the documentation, and because of the great variety in farming systems, the current status and future challenges are best discussed in terms of the broad systems in which these animals exist.
Grassland Systems Pastoral systems account for approximately 2/3 of the worlds utilised agricultural area, and are for the most part used for cattle and sheep production. Because stocking rates are low, they account for some 12% of the approximately 900 million cattle in developing countries, and 15% of the 1100 million sheep and goats. These systems are relatively of greatest importance in Latin America. Of particular importance from the point of view of biodiversity are the populations of Andean Camelidae, alpaca, llama, vicuña and guanaco (see box 1). In the humid and subhumid tropical grassland systems of Latin America, cattle predominate. The genetic resources have three origins: the original Criollo types, which are Bos Taurus cattle with 500 years of adaptation to tropical conditions; Bos Indicus breeds derived from importations from India in the last century; European and North American breeds, also imported in recent times. From the point of view of resource conservation, attention should focus on the documentation and protection of the remaining Criollo breedsA14.
Box 1 Genetic resources of the Andean CamelidaeA11
The camelidae evolved in the new world, and four species
survive in Latin America. These are the llama and alpaca (both domesticated) and
the vicuña and guanaco. They formed the mainstay of Andean agriculture in
the pre-Columban period. They have been largely replaced by cattle and sheep.
Today, there are approximately 3 million each of alpaca and llama, mainly in
Peru and Bolivia, and smaller numbers of the non-domesticated species. Most
alpaca and llama belong to small farmers in the more difficult Andean areas
above 3,000 metres. Data on fertility, mortality and growth all indicate low
productivity. Nevertheless, these populations have held their place in
competition with other species because of their adaptations to climate and
Mixed farming rainfed systems Over 60% of developing country cattle, 55% of sheep and goats, and about 70% of pigmeat production relate to these systems. They are therefore the dominant forms of livestock use in tropical countries. The largest challenge is likely to be in Asia, which accounts for 42% of developing country cattle, 46% of sheep and goats, almost 90% of pigmeat production, and practically all of the worlds buffaloes.
Among the major challenges are:
· The rapid genetic erosion of Chinas breed resources in pigs, which include over 100 separate breeds, many with distinct characteristicsA7.In some countries, for example India, government and non-government agencies have well-developed programmes of support and conservation for local genetic resources. In most others, such infrastructure is absent. There is therefore considerable need for research, documentation and education activities in this area.
· Guiding and managing the massive transformation of dairy cattle populations in countries like India, where cross-breeding of local breeds with introduced strains is proceeding on a massive scaleA2, A3.
· Conservation of the non-cattle bovid species (Yak, Gaur, Mithun, Banteng).
· Conservation plans for the regions unique buffalo resourcesA1, A9.
· Genetic planning appropriate to the expansion of use of small ruminants, rabbits and other species in mixed farming systemsA4, A5.
Mixed farming irrigated systems These systems have a surprisingly high livestock component. In Asia, where the systems are most prevalent, they account for more than half of the cattle, sheep, goat and buffalo populations. This reflects the close involvement of the animals in the farming system.
The genetic future of the livestock populations must be considered in the context of this close integration: the predominant work role, the feed base which is almost exclusively crop waste; and the relatively high value of dung for fuel.
Landless systems Pigmeat production in the developed world has moved almost entirely to industrial scale units which are divorced from their feed sources. Production in Asia is rapidly moving in the same direction. In 1994 it was estimated that some 30% of production came from such systems. Similar trends are underway in poultryA8. An inevitable consequence of this trend is a move away from local genetic sources to internationally competitive stock and husbandry systems. The growth of these systems therefore accentuates the need for conservation activities focused on livestock populations which still persist in traditional systems.