Alimentary infertility in female cattle: Part ІІІ – the modulation of reproductive function with vitamins and plant derivatives (Overview)

Abstract

Vitamins are involved in the synthesis of several organic compounds serve as coenzymes. Therefore, they are necessary for different processes such as metabolic regulation, the course of many biochemical reactions, the processes of cellular respiration, the maintenance of acidbase and electrolyte balance, and the protection of cells from oxidative stress. Thus, they support various body functions, including reproductive ones. Consequently, using diets that are not balanced in the composition of micronutrients and, in particular, vitamins can lead to several pathological conditions that affect their reproductive function and the state of the offspring. A deficiency in vitamins often results in reduced enzyme activity. Thus, specific metabolic processes are inhibited, including those in the endocrine glands associated with animal reproduction (such as the pituitary gland, adrenal glands, and ovaries), leading to disruption in the synthesis of gonadotropic and sex hormones. Delayed puberty, disruption of sexual cycles and ovulation, low fertility, and perinatal losses (impaired development and survival of embryos, early death and abortions, osteodystrophy in pregnant women, impaired development and skeletal defects in the fetus, and weak or dead offspring) are registered. Premature births occur, the contractility of the uterus and expulsion of the fetal membranes decreases, and postpartum activity is disturbed. Additionally, the period of manifestation of the first estrus after calving is prolonged, and inflammatory processes such as placentitis, cervicitis, metritis may develop. Moreover, milk fever may occur along with an increase in the frequency of cystic and atrophic ovaries. With excessive or long-term consumption of phytoestrogens, violations of the sexual cycle (from anestrus to nymphomania) can occur. Changes in the structure (cysts or their compaction) and function of the ovaries (synthesis of hormones in the follicles and corpus luteum), hyperemia of the mucous membranes, edema of the reproductive organs and post libido metrorrhagia are observed. Other effects may include prolapse of the vagina, cystic hyperplasia of the endometrium and purulent inflammation of the uterus, the onset of heat during pregnancy, a decrease in the frequency of fertilization, an increase in the loss of embryos, and the death of the fetus, difficult births, a high percentage of stillbirths. Thus, vitamins and biologically active substances of plants significantly impact the reproductive function of animals, so regulating their supply to the body of cows and heifers is an essential factor in ensuring the proper level of herd reproduction.