Exogenous factors of nuclear DNA fragmentation in bulls sperm

Herd reproduction is the most important indicator of the economic efficiency of the industry. Assisted reproductive technology, especially artificial insemination, is widely used in dairy farming. When using this method, tens of thousands of cows and heifers are inseminated with the seed of a single bull, therefore, the used biomaterial must meet high requirements, since the use of low-quality sperm products can lead to multi-million losses. The reproductive performance of breeding bulls depends on numerous biotic and abiotic factors.
breeding bulls depends on numerous biotic and abiotic factors. The purpose of the study the influence of meteorological factors on the biological usefulness of sperm from bulls of different breeds. A multidimensional dispersion analysis of the effect of temperature and geomagnetic activity on the quality of spermatozoa was performed. The results of multidimensional dispersion analysis show that the combination of temperature factors with geomagnetic activity has a statistically significant effect on the content of spermatozoa with abnormal movement in the fresh seed and on the activity of spermatozoa (p<0,05). Geomagnetic activity (K-index ≥5,0) leads to an increase in the proportion of spermatozoa with pathological morphology. This trend was observed regardless of the season of the year. During the summer period, on days with increased geomagnetic activity, the content of spermatozoa with pathology increased by 66% compared to the period when there is no magnetic disturbance. Under the influence of geomagnetic activity, the proportion of spermatozoa with abnormal movement increased – such spermatozoa in the ejaculate contained an average of 10,2%, depending on the season and temperature, this indicator varied from 6 to 21,5%. High geomagnetic activity and temperature lead to an increase in the proportion of spermatozoa with a violation of the structure of nDNA.