Relevance of the topic. Given that the dog is one of the best laboratory models, in particular for studying comparative aspects of reproductive physiology in mammals and humans, a better understanding of the mechanisms involved in the establishment and maintenance of pregnancy may be useful for establishing the pathogenesis of some pathologies and will contribute to the development of better clinical protocols.
Despite the large number of publications on the regulation of sexual cycles and luteal function of the corpus luteum in animals and humans, the question of the influence of individual characteristics of the organism (age, fatness, temperament) on the dynamics of sex hormones in blood plasma during the sexual cycle of bitches has remained beyond the minds of researchers. In this regard, from a scientific point of view, it is important to investigate the individual characteristics of the neurohumoral regulation of the reproductive function of bitches, in order to take into account the established features in reproduction.
The sexual behavior of bitches during monoestrus is largely limited by the balance of hormones, characterized by typical behavioral acts, however, the degree of their manifestation is individual, which depends, in particular, on the temperament of the animals. Therefore, knowledge of the main reproductive aspects of the relationship between the dynamics of the content of sex hormones and the main features of the temperament of bitches is important for a better understanding of animal ethology and reproductive biotechnology.
Therefore, a relevant direction of scientific research is the study of the physiological features of the neurohumoral regulation of the reproductive function of bitches of the Bull Terrier breed, which will allow developing an individual approach to animal reproduction, which will contribute to increasing the productivity of bitches and the viability of the offspring.
Purpose and objectives of the study. The purpose of the study was: to find out the individual features of the neurohumoral regulation of the reproductive function of bitches of the Bull Terrier breed.
To achieve the goal, the following tasks were solved:
− to establish the influence of pregnancy on the dynamics of the level of sex hormones in the blood of bull terrier bitches;
− to investigate the dynamics of the content of sex hormones in the blood of bitches of different ages;
− to establish the dynamics of the content of sex hormones in the blood of bitches of different fatness;
− to establish the degree and nature of the influence of temperament traits on the dynamics of the content of sex hormones during the sexual cycle;
− to investigate the physiological features of the manifestation of prenatal stress in bull terrier bitches;
− to develop a comprehensive reproductive protocol and establish its effectiveness.
The object of the study is the neurohumoral regulation of the reproductive function of bull terrier bitches.
The subject of the study is bull terrier bitches, the dynamics of the content of sex hormones, temperament traits, behavior.
Scientific novelty of the results obtained. For the first time, a physiological assessment of the neurohumoral regulation of the reproductive function of bull terrier bitches was made. Based on the assessment of the dynamics of the content of sex hormones in the blood of bitches of different fatness, age and temperament, individual features of the reproductive function of bitches were established and the degree and nature of their influence on the level of sex hormones in the blood of bitches were determined.
For the first time, the degree of influence of pregnancy on the dynamics of the content of sex hormones in the blood plasma of bitches of the Bull Terrier breed during the sexual cycle was established. In particular, throughout the entire period, pregnancy affects the level of luteinizing and follicle-stimulating hormone in the blood plasma of bitches – Ҳ²ᵪ=0.19–0.48 (P≤0.05–0.001). Pregnancy affects the content of estradiol only on the 23rd–30th day after the LH surge – Ҳ²ᵪ=0.18 (P≤0.05).
For the first time, the degree of influence of the age of bitches on the dynamics of sex hormones in their blood was established. In particular, in older bitches (8–9 years old), age affects the level of follicle-stimulating hormone (on the 4th, 9th and 23–30th day after the LH surge – Ҳ²ᵪ=0.43–0.48; P≤0.05) and progesterone (on the 9th and 35–40th day after the LH surge – Ҳ²ᵪ=0.50-0.52; P≤0.05).
For the first time, the degree of influence of the fatness of bitches on the content of sex hormones in their blood has been established. Thus, excessive weight of bitches affects the level of progesterone on the 4th, 9th, 35–40th and 55–60th day after the LH surge (P≤0.05); follicle-stimulating hormone on the day of the LH surge and on the 2nd day of it (P≤0.05); luteinizing hormone on the 55th–60th day after the LH surge (P≤0.05).
