The materials of the study were the results of insemination effectiveness of dairy cattle with the semen from 12 specialized bulls breeds: Belgian Blue, Charolais, Limousine, Simentaler. Inseminations where conducted on Mazowieckie, Warmińsko-Mazurskie and Podlaskie Voivodships of Poland. Data gathered in database involved the breed, genotype of the bull’s father and, the inseminator. The influence of three factors on insemination effectiveness was analyzed. Within the Project “The optimisation of beef production in Poland in accordance with a fork-to-farm strategy” 1678 dairy cattles were inseminated out of which 442 were inseminated effectively. Insemination was performed by 24 inseminators. No significant dependence of bull’s breed, bull’s father genotype or inseminator on effectiveness of conducted inseminations was observed. However the influence of the inseminator’s sex on effectiveness of inseminations where observed. Basing on conduced analysis, it was found that there is a need for further detailed studies on other factors which might affect the effectiveness of artificial insemination. The factors that may have an impact on reproductive rate are: individual inseminator’s characteristics (education, experience, inseminator’s behavioral traits, including scrupulousness and reliability), as well as inseminated of cross calves (age, the last successful insemination, etc.).

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