The objective of the study was to evaluate inbreeding and genetic diversity inSlovak Spotted cattle. Reference population contained genealogic information on36949 animals (129 sires and 36820 cows) that were used in the analyses. Pedigreecompleteness indexes in the first three generations were on the level of 100 %, inthe 5th generation it was 60 %. Since 1970, inbreeding trend was positive withsignificant increasing in 1990. Average relationship was 0.8 %, inbreeding rate0.36 % and ΔF = 0.094 %. In the reference population 43 % animals was inbred, 68% of sires and 33 % cows, with also 67 % purebred cows, as well. Total geneticdiversity loss in the reference population and population of cows was the same,closely under 1%, in purebred cows 1.19 % and sires even due to higher inbreedinglevel 1.78 %. Genetic diversity loss was more influenced by the genetic drift 0.80%in the reference population, 1.47% in sire group, than by effective number offounder unequal contributions. F statistic showed fines superiority ofheterozygosity by sire lines subpopulations, in the whole sire group (FIS = - 0.12)and their minimal differentiation (FST = 0,098). Obtained results showed thatinbreedization process started in this population. Monitoring and better geneticmanagement are important from the point of its further sustainable development.

ABSTRACT:The aim of the present paper was to simulate the scenarios for a maximum avoidance of inbreeding (MAI) mating strategy, and compare it with a random mating alternative, with the main focus on inbreeding and development of the genetic gain. The parameters of the simulation were based on the structure of the Slovak Pinzgau active population of 2868 animals (930 purebred cows). The selection under a total merit index (TMI) was simulated, covering the milk, survival, and live weight breeding value estimation results. The heritability of TMI (h 2 = 0.09) was estimated using a REML single trait animal model. Alternatives assumed a closed population structure, fixed number of mating per parent, and equal use of sires in insemination. Animals in generation 0 were set as founders without pedigree information. In separate simulation runs, the number of sires of sires was set at 2, 4, 5 or 10 mated with 40 dams of sires in all cases. The sex ratio of the offspring was assumed to be 50/50 male/female. Twenty consecutive generations were simulated for both random and maximum avoidance of inbreeding mating, which resulted in a total of 8 scenarios. Significant positive differences in genetic gain were observed in the MAI mating system with 2 (0.74**), 4 (0.24**), 5 (0.13**) or 10 (0.09**) sires in comparison to random mating design. When using MAI, significantly lower inbreeding was observed with 2 (5.44**), 4 (3.18**), 5 (2.43**) or 10 (1.16**) sires. Simulation results showed that the use of a maximum avoidance of inbreeding mating strategy would lead to significantly decreased rates of inbreeding while maintaining suitable levels of genetic gain in the Slovak Pinzgau population.