Rozdíl v genových a genotypových četnostech mléčného proteinu kapa-kaseinu u býků nabízených do inseminace a jejich skutečný podíl v populaci krav

Abstract

The aim of this study was an evaluation of allele and genotype frequencies of Milkprotein kappa casein (CSN3) in bulls offred by breeding companies (n = 287) and of a real proportion of these fathers (genotypes) in a population of Czech Fleckvieh cows (n = 27 970) born between 1994 and 2004. An ave­ra­ge frequencies of genotypes of the offered fathers and their real proportion in a population of cows was in 1994–2004: AA = 0.3902; 0.4572; AB = 0.4774; 0.3993; AE = 0.007; 0.0004; BB = 0.115; 0.1394 and BE = 0.0105; 0.0036. EE genotype was not found. An average frequency of allele was A = 0.6324; 0.6571; B = 0.3589; 0.3409 and E = 0.0087; 0.002.The set of observed cows (27 970 head) shows a significant predominance of using fathers with AA and AB genotypes of milkprotein kappa-casein. A frequencies of these two genotypes varied between 0.7885 and 0.9836 in the observed years. A difference between genotype frequencies of CSN3 (AA, AB and BB) in offered bulls and their real proportion in the population of cows was not significant only in years 1995, 1996, 1998, 2002 and 2003. In the rest of the years (1994, 1997, 1999, 2000, 2001, 2004) and also in average of all years the difference was significant or highly significant.In none of the observed years (1994–2004) were the absolute frequencies of genotypes of the cows‘ fathers in genetic equilibrium. Genotype frequencies of milkprotein kappa-casein of the offered bulls and their real proportion in the population of cows show, in most of the years, significant or highly significant differences. A variability of heterozygosity in 1994 – 2004 was very high, between 14.03 % and 85.68 %. Gene diversity varied between 34.9 %–49.59 %.PIC value varied between 0.2882–0.3767 in 1994–2004 and its average in all the observed years was 0.3516.When counting allele and genotype frequencies in a population with a different intensity of use of several bulls it is important not only to analyze a particular genotype of the father but also his share of influence in the population of cows.