RASY BYDŁA – WSPÓŁCZESNE SPOJRZENIA NA ICH POCHODZENIE I KRYTERIA KLASYFIKACJI: PRACA PRZEGL ˛ADOWA

Abstract

Domestic cattle descend from the aurochs, a species of wild animals, inhabiting forests of Europe and Asia in the past. The results of genetic studies allow concluding that the world cattle population originate from 80 female aurochs domesticated in today's southeastern Turkey. After 10,500 years the worldwide bovine population has exceeded 1.4 billion, with two subspecies: taurus cattle (Bos taurus) and zebu cattle (Bos indicus). The former was first scientifically described by Linnaeus, who in 1758 proposed its name, used until now. The processes of cattle domestication and improvement have led to more than 1000 distinct breeds. During the last two centuries several kinds of classification have been developed in order to identify cattle breeds. Several criteria have been used, such as basic cranial type, length of the horns, skull shape, degree of domestication, production purpose, type of ancestral aurochs, geographic distribution, place of breed origin, population size, growth performance, biochemical polymorphisms and molecular-genetic methods. At present the attention of cattle farmers around the world has focused on the most productive improved breeds at the expense of less productive local ones. Modern methods, such as artificial insemination and embryo transfer, have allowed unlimited spread of breeding material around the world. This way, it has become possible to use reproductive material of different cattle breeds on an unprecedented scale in many countries. At present, many of the latter have disappeared, or their population is on the verge of extinction.