Biotic and Abiotic Factors of Sperm nDNA Fragmentation in Farm Animals

Infertility and subfertility are among the global challenges of our time. Fertility in livestock farming is not only biologically important, it is also economically important. The aim of this study was to study the effect of these factors on sperm chromatin nucleus and to assess the impact of the fragmentation index degree on bull reproductive performance. The influence of abiotic factors such as ambient temperature, the level of geomagnetic activity and the biotic factor-infectious diseases of male reproductive organs - was studied. At high ambient temperatures (28-30°C), the proportion of sperm with damaged DNA increased by 70% compared to temperatures below 15°C. A Multivariate Analysis Of Variance (MANOVA) confirmed the influence of the geomagnetic activity factor on the degree of nuclear DNA fragmentation in bull sperm cells (level p<0.05). During the summer period, on days with increased geomagnetic activity, the Nuclear DNA fragmentation index in the samples studied was 20.5%. In some of the samples studied, this index exceeded 38% and the coefficient of variation for this index reached 44%. The proportion of sperm cells with abnormal movement also increased during geomagnetic activity. The content of such sperm cells reached 9.1% in bull semen ejaculates obtained during the winter period. More than 12% of sperm had non-progressive movement in summer semen obtained with a K-index ≥5.0, which was 83.8% higher than with a K-index ≤1.0. High geomagnetic activity and temperature and infection of the reproductive organs lead to pathological changes in spermatozoa, an increase in the proportion of spermatozoa with damaged nuclear DNA and a decrease in fertility.