Changes in the genealogical structure of the brown swiss cattle during breeding

The population of the Brown Swiss cattle is differentiated into 12 lines and related groups, 65.2% of which are animals of the genealogical groups Meridian 90827, Master 106902, Concentrate 106157 and Hill 76059. Animals belonging to the line Nevod 3313 have disappeared. Total number of Brown Swiss  animals in the lines of Amur 3033, Baro 18, Sector 4272-about 1.5%, in the line of R’yany 1318-0.03%. There is an accumulation of genetic material of the Brown Swiss breed of American selection and the displacement of genes that were possessed by animals of the local Brown Swiss cattle of domestic selection. For this reason, alleles B1G2QT1A`1P`, B1I`Q', I1E`3G`G``1 are eliminated from the breed, their frequency of occurrence in the herd is 0.005 or less. Marker EAB alleles B1G2QT1A`1P`  and B1I`Q' in the Baro 18 line were detected in 5.1% and 6.4% of animals, respectively, in the Amur 3033 line I1E`3G`G``1 is found in 15% of offspring. In 2018, 61 EAB locus alleles were identified in the lines, their number varies from 15 (line Laddi 125640) to 56 (line Meridian 90827). Studies have shown that the largest distribution (more than 60%) is characterized by EAB alleles of American selection, especially B1P2Y2G`Y`, B2G2KY2E`1F`2O`G``1, B2O3Y2A`2E`2G`P`Q`Y`, G3O1T1Y2E`3F`2G``2, I1Y2E`2G`I`G``1 (?q=0.479). The G2E`3F`2O` allele is extremely rare. EAB-alleles characteristic of domestic breeding were detected in 35% of animals. Among them, G1O` (0.067) and the recessive EAB b allele (0.106) are widely distributed. Alleles B1I1T1A`1P`, B1I`P`, B2P2T2P`B``, I`Q`, P2(E`3)I`  are eliminated from the breed (?q < 1%). Alleles of the Jersey cattle were found with a frequency of 0.046.The alleles G2O2E`2I`  (line Hill 76059 – 20.5%) and O2E`2G``1 (line Meridian 90827 – 4.3%) were widely distributed.