EN
Directional selection aimed at improving productive traits in pigs has caused limitations in adaptive mechanisms, affecting also, to some extent, the health of these animals. The article shows some health problems in swine, being a consequence of directional selection. It also refers to results obtained in studies within molecular genetics, cytogenetics and immunogenetics, showing an improvement in genotypes, and to some methods for prevention and control of several dysfunctions connected with some infectious diseases in pigs.