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Heredity of polledness in cattle
HEGROVÁ, Kateřina
Most cattle breeds were originally naturally horned. The horns were used as a tool of defense and a manifestation of dominance in the herd. With increasing pressure to increase the efficiency of breeding and increase the safety of both animals and care-givers, horned cattle are being dehorned. However, this does not correspond with welfare requirements. In 2009, the complete genome of cattle was sequenced, which started a series of researches in the field of heredity. Genetic manifestations of horns or polledness are controlled by the autosomal locus polled, located on chromosome pair BTA1, characterized by two alleles, for the dominant P allele representing polledness, and for the recessive allele p for horns. In cattle we encounter 4 mutations of these alleles Celtic, Frisian, Mongolian and Guarany. Manifestations of polledness are also influenced by alleles for the presence of scurrs Sc and sc, or alleles for the manifestation of the so-called African horns Af and An. Thanks to the testing of individuals using microsatellite markers or the SNP method, it is possible to mark genetically polled individuals and thus help breeders to expand hornless breeds.
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