Health in contemporary cattle breeding

English. 61, XXX). Autosomal aneuploidies were not found. Robertsonian translocations were occurred in 0.82 % of Czech Simmental sires and in 3.57 % of beef sires, whilst Holsteins were not affected. The estimate of genetic variance of stillbirth caused by sires was 1.90 %, and heritability - 0.078, but the sizeable influence of sire´s line was observed. Despite of the low genetic variance, it is recommended that sires with higher incidence of fertility damages should not be used for breeding. In the period of genomics, molecular biology and molecular cytogenetics, the opportunity arises to solve the problem of genetic health principally.

English. The paper deals with the genetic health of cattle. The studies done in the Czech cattle population are summarized. The strict measures taken for BLAD in the 90´s have been efficient, as the frequency of positive sires has decreased rapidly. The diverse approach to Complex Vertebral Malformation (CVM) resulted in different population dynamics. The use of proven heterozygous carriers of lethal alleles in breeding is not absolutely banned, so the rate of heterozygous sires decreases, but persists still considerably, and the occurrence of CVM females remains high. Recessive alleles of bovine citrullinaemia, DUMPS, glycogen storage disease V and II, and factor XI deficiency were not found. The occurrence of congenital defects was analysed. The XX/XY chimerism was found in 0.50 % of Holstein-Friesian sires and in 0.74 % of Czech Simmental sires. By testing for aneuploidy, 5 Charolais sires were found to be carriers of a redundant sex chromosome (61, XXY