The pig breeding is always accompanied by losses in all phases of reproduction and production cycle with an unfavourable effect on breed profitability. The losses level is going to be the phenomenon, which significantly influences competitive advantage between breeders and in international scale too. The important progress and homogenization of carcass quality has been achieved in recent years (in the Czech Republic and in Europe) but we have noticed high differences in reproduction results in the CzechRepublic and abroad. It means that management empiricism is not sufficient in many pig herds because they have not a new acceptable research knowledge and tools for their application in practical conditions. It gives reasons for insertion necessity of this problem in the research sphere. A high variability in ejaculate quality in boars selected for insemination, losses caused by piglet mortality and ineffective gilts introduction in breeding are the main problems in the countries with developed pig b