Under optimum conditions, the native semen is characterized by a determined number of atypical cells and this means a normal phenomenon. The increased deviations from the researched index may serve as a sign of reproductive system functional activity maladjustment. The exposure of animals under the influence of environmental stressors influences on all body systems and this leads to the development of a state of stress, that manifests itself in loosing the capacity of forming the protective barrier and maintaining the balance of body’s internal state. Under the influence of stressors, functional changes in the activity of the reproductive system appear. Stressors influence on the spermatogenesis and also they can change the morphological structure of male sexual cells that can have a negative influence in the process of ovule fertilization. The purpose of the researches was to study the influence of the maintenance conditions on the quality of bull and rooster semen. As object of study there were used breeding bulls of speckled-black race and roosters, including the semen collected from these animals after being exposed to stressors. There were used microscopic methods for determining the morphology of the semen, the nociceptive stressing method, the method of colouring the gametes and the method of studying the gametes acrosomal system. It was realized the analysis and classification of the pathological forms of the gametes in the bull and rooster semen. In the early stages of the study, there was evaluated the amount of the pathological spermatozoids in the rooster semen, kept in comfortable conditions. The results proved that the pathological forms reach the level of 16.6±1.92 % in the semen. Among gamete pathologies there were observed: microspermatozoids, spermatozoids with aproximal straw, spermatozoids with twisted tail, macrospermatozoids, spermatozoids with broken heads and spermatozoids with ripped tails. The microspermatozoids and the spermatozoids with protoplasmic drop were detected in larger amount, respectively, 3.7±1.09; 3.3±0.65%. The macrospermatozoids were detected in a smaller amount (1.7±0.74). After rooster nociceptive stressing the percentage of gametopathologies has risen by 3.7 % and reached the level of 20.3±2.32%. In this case, the quantity of spermatozoids with twisted tail increased from 2.7±2.49% to 9.3±1.68%. The results of the experiments prove that the percent of atypical cells has grown to the maximum amount of 24.7±2.49% until the 45 day of the trials, but from day 61 to day 88 it was observed a totally azoospermia. A similar study on breeding bulls proved that the amount of gamete pathologies in the period before stressing was 13.2±1.2%, whereas the number of spermatozoids with normal morphological structure achieved the level of 86.8±1.2%. Already on day 17 after exposure to stressors it was observed an increase of gamete pathologies to 30.7±2.75%. The biggest changes were observed in the day 53 after the animals were stressed, so the amount of gamete pathologies reached the level of 86.7±2.01%. This quantity persists for a period longer than 55 days, after this period it lowers a little, but anyway it is maintained on a high level for a period of 140 days. Consequently, only the spermatozoids that totally preserve their morphological structure can manifest functional activity. This determines the path of significant vital processes. Because of this, determining the amount of pathological cells is very important in developing the processes of increasing the results of animals’ reproduction. Based on the study carried out, it can be concluded that: 1) The semen of roosters that were kept in comfortable conditions has a bigger percent (16.6%) of gamete pathologies, in comparison with the semen of bulls (13.3%), also kept in comfortable conditions. 2) At the breeding bulls exposed to nociceptive stressing, unlike roosters, the maximum amount of pathological spermatozoids was observed on the 53rd day after steaming stress and that was lasted for a period of 2 months, until that was minimized.