The results of research to identify the impact of various gene-and paratypic factors for the implementation of reproductive qualities of pigs of four gene pools of herds Ukrainian steppe white and spotted breeds. It was found that the investigated symptoms are determined by the breeding value of boars substantially. The impact of the genotype of the father in the total variability of prolificacy and weight of jacks at weaning piglets in the experimental herds is 0.5 ... 39%. Influence of belonging to a family and lines is insignificant – 0,3 ... 2,6 and 1,1 ... 3,9%. Among the paratypic factors, the most significant impact on the variability of selected traits has a "year of using sows" (1,3 ... 35,6%). The level of influence the factors "age of the productive use of sows" and "complex conditions", that are specific to each of the controlled farms, is respectively 1,4…10,6 and 4,0 ... 21,2%. The differences of genotype pigs of Ukrainian selection according to the traits of adaptive capacity - namely, ductility and stability are found. The results, which were obtained, are complementing the existing and introducing new elements into the theoretical and practical bases of breeding pigs