The concept of breed is one of the most controversial within the natural sciences. Farmers play an essential role in identifying and defining a breed; a livestock breed is one that is recognized as such by a group of farmers. According to scientist Jay Laurence Lush, for example, "no-one is authorized to assign a scientific value to this term. It is the farmers' word, which we must accept as the correct definition." That said, it is possible to define a breed as a group of domestic animals from the same species with defined and identifiable exterior traits (passed on to descendants through heredity), which can be distinguished and separated from others of the same species on the basis of visible characteristics (size; color of coat or plumage; shape of the head, limbs, horns, tail, etc.).
A breed can be defined as native when its characteristics are linked to a specific area of varying size where it has developed or naturally adapted over time (for cattle, it takes at least six generations to fix the characteristics of a breed).
Some examples of breeds are Mirandaise cattle, a beef breed originally from Gers, a department in the Midi-Pyrénées region of France; the Saluzzo white hen from Piedmont, Italy; and the Villsau sheep from Norway's northwest coast, one of the oldest sheep breeds still surviving in Northern Europe.
Native breeds adapt better to the climactic, geographic and socioeconomic conditions of a place, and in extreme environments they require less attention and less food.
For a breed to be officially defined as such, it must be registered. The registration of a breed occurs only following a request by a group of farmers.
Breeds originate in specific places, but in some cases-and this usually happens because some of their characteristics are particularly useful-they can spread to other parts of the world. A breed might be at risk of extinction in its native area but common in other parts of the world, like the Toggenburg goat, originally from the Swiss canton of St. Gallen but now found in many other Alpine regions.
In the Ark of Taste, it is always important to link the breed to a food product, such as meat, milk, a cheese or a cured meat.
The Worldwatch List of Domestic Animal Diversity, published for the first time in 2000 by the United Nations Food and Agriculture Organization (FAO) and Environmental Programme (UNEP), is a reference point for domestic breeds at risk of extinction around the world. According to the report, every week the world loses two animal breeds raised by humans, we have already lost a thousand breeds over the past century and a third of those still existing (over 2,000) risk disappearing in the next 20 years. Once a breed is extinct, it is gone forever.
One of the greatest dangers to domestic animal diversity is the export of animals from the global north to the global south, which often leads not only to hybrids but also the complete replacement of local breeds, which are considered to be less productive than those from industrialized countries.