Репродуктивні якості свинок різних порід

Abstract

Intensive managing of the pig industry requires the use of specialized high productive breeds of pigs, at the same time demanding the creation of optimal conditions for feeding and retention to show their reproductive capacity, especially at the beginning of their sexual cycle. The purpose of the study was to investigate the correlation between the reproductive qualities of gilts of different breeds with their hormonal background during the sexual cycle. The experiment was performed on clinically healthy pigs, selected on the principle of analogues in two experimental groups of 5 heads in each: the Pietrain breed and Large White breed. The evaluation of the hormonal status of pigs was carried out based on the results of the determination of the concentration of testosterone and estradiol in blood serum during diestrus and 24 hours after the establishment of standing reflex (estrus). Artificial insemination (intracervical) of the pigs was carried out after 24 and 36 hours after the establishment of a standing reflex, depending on the manifestation of the signs of the oestrus. The evaluation of reproductive qualities of the pigs was carried out according to their fertility, multiplicity and mass of piglets at weaning at two months of age. The experimental data obtained during our study testifies that the breed factor significantly influenced the time of the onset of the first oestrus - in the Large White breed on the 145th, and the Pietrain breed - on the 166th day of development of the pigs. With an increasing in the number of sexual cycles, in general, there was a normalization during the second sexual cycle in the direction of reduction - in the Large White breed - to 24 days, and the Pietrain breed – to 27 days. It was established that the pigs of Large White breed are fertilized by 15% better than pigs of Pietrain breed. The revealed differences are due to the peculiarities of their hormonal background. Thus, the factor of the genotype had a significant effect on the reduction of the testosterone content in the period of the oestrus by 16.6% in the Large White breed, while in the Pietrain breed - increasing of level of this hormone by 37.5%. The concentration of estradiol in the excitation phase increases almost equally in animals of both breeds, against a background of a sharp decrease (in comparison with diestrus) of the level of progesterone in the pigs of a Large White breed in 4 times (p <0.01), Pietrain breed in 3.2 times (p <0.05). A more pronounced relationship between the level of hormones with individual reproductive qualities in the piglets of the Pietrain breed, relatively to the Large White, was noted. The existence of a significant correlations between the level of progesterone in the piglets of the first genotype with the number of piglets at birth (r = 0.79), weaning (r = 0.68) and weight of the nest at 60 days of age (r = 0.70) were established. In sows of Large White breed, a significant effect of blood serum testosterone concentration on live weight of piglets at birth (r = 0.79) was founded.