Factors determining sperm fertility

The purpose of the work is to to systematize scientific data on factors affecting sperm fertility. Sperm fertility is the ability of a sexually mature organism to reproduce offspring. It is determined by parameters such as sperm motility and the quantity of normal and pathological sperm forms in the ejaculate. The fertility of male producers is acquired in stages: spermatogenesis occurs at the beginning, then the spermatozoa mature in the epididymis. The epididymis plays a significant role in making sperm fertile. Maturation occurs due to a complex of substances produced by the epididymis, and the full maturation of spermatozoa occurs in the genital tract of the female. Thus, fructose, produced by the vesicular glands, affects the fertility of animals. Another substance found in seminal plasma is citric acid, which takes part in the acrosomal reaction. Fertility is influenced by such factors as: the age of the animal, breed, the health of the male's reproductive system, heat stress and others. For instance, as animals age, the number of pathological sperm forms increases in the ejaculate, and their motility decreases. The same happens in cases of inflammatory diseases of the male reproductive system. Changes in the qualitative characteristics of sperm were recorded among Simmental and red breeds, as well as Holstein-Frisian and Jersey breeds. Prolonged or severe heat stress can also have a negative impact on fertility, despite the presence of compensatory mechanisms. These mechanisms are maintained by the presence of sweat glands in the scrotum, which are innervated by sympathetic nerves, as well as a reflex arc between the scrotum and the respiratory center. When the scrotum's temperature rises, respiratory rate increases, facilitating cooling. Furthermore, sperm activity can vary depending on the season. In animals with seasonal reproductive activity, sperm fertility parameters are better during the breeding season.In summary, sperm fertility is a multifactorial process, the success of which is mainly due to the health of the male reproductive system and the presence of many compensatory and adaptive mechanisms.