young pigs can be bred and fertilized at the age of 5-6 months. However, due to the underdevelopment of the genital organs, they are not yet ready for normal fruiting and growing strong, healthy piglets, well adapted for further use.
The desire of some pig farmers to quickly get piglets and recover the costs of buying and raising pigs leads to serious mistakes. The mating at an excessively early age leads to a delay in the development of the queens themselves, a decrease in multiple pregnancy, the birth of small, weak piglets with an increased susceptibility to diseases. Covering queens at 6-7 months of age results in 6-8 piglets at birth, 6-7 piglets at weaning.
Pigs born at 7-8 months of age have 8-8,5 piglets, 9-10 months old – 9-10, 11-12 months old – 10-11 piglets.
The age of the first coat of young animals also affects the development of the mammary glands. In 11-12-month-old pigs covered with a live weight of 120-130 kg, the glandular tissue of the mammary gland is formed into clearly visible lobules, in each of which the alveoli are fully developed, in some alveoli, the presence of a secret is visible. In pigs 9-10 months of age, a clear lobulation of the gland is expressed, there are alveoli, but there is no secret in them yet. In pigs covered at the age of 7-8 months, with a live weight of 70-85 kg, glandular tissue lobules have not yet formed, there are no alveoli, therefore their milk production is much lower, which negatively affects the safety and development of piglets.
High fertility and milk production, good maternal qualities and viable young, suitable for intensive fattening, give young pigs at the first coating at the age of 9-10 months with a live weight of 120-130 kg. In order to achieve such development, the average daily growth of gilts in rearing must be at least 500 g, which is possible only if they are fully fed. Too high increments when growing future queens are also undesirable – this leads to excessive salting of animals and a deterioration in the quality of the offspring.
Growth of rearing gilts should be lower than that of fattening gilts, and this is achieved by rationed feeding.
The effectiveness of insemination (mating) largely depends on the ability to determine the time of estrus in a sow, which in turn is due to the knowledge and ability to use this phenomenon. The complex of physiological processes that repeat in the body of a female in a certain sequence is called sexual cycle. It consists of several phases, or stages, according to which characteristic changes occur in the sexual behavior of the uterus and the functions of the reproductive apparatus.
Excitation stage characterized by changes in the external genital organs: they noticeably swell, turn red, the genital loop relaxes, anti-peristaltic movements are noticeable, and sometimes expiration. This is estrus, indicating the maturation of the follicles and the release of follicular hormone. As the follicles mature, estrus intensifies. Gradually, the uterus increases anxiety. Most of the time they move, squeal, show a hug reflex. Their appetite is reduced or completely absent.
The period of increased sexual activity turns into hunting – the uterus shows a reflex of immobility and allows the boar to cover.
Timely determination of the start of estrus in sows is one of the most important elements in the organization of intensive reproduction of the herd. The onset of estrus in pigs can be detected by checking with a probe boar or by pressing a fist on the lower back. The stage of sexual arousal lasts 3-5 days, and estrus lasts from 36 to 90, sometimes up to 120 hours. ovulation. The release of eggs from the follicle in overgrown queens occurs 18-24 hours after the start of the hunt, in replacement pigs – after 24-30 hours.
On average, the duration of ovulation is 10-15 hours, sometimes from 1-3 to 24-48 hours.
Deceleration stage occurs after the end of the hunt and is characterized by a weakening and cessation of signs of anxiety, restoration of appetite, and a negative reaction to the probe boar. During this period, pigs are characterized by a state of depression, “sleepy” behavior. They lie a lot, reluctantly get up, walk behind the herd.
At this stage, the swelling of the tissues of the external genital organs disappears, the vulva is wrinkled and retracted. The genital loop is tightly compressed, the vaginal mirror is inserted into the genital tract with difficulty. In place of the ovulated follicle, a corpus luteum develops in the ovary. The period of extinction of sexual arousal lasts 5-7 days.
Stage of balance characterized by the absence of estrus and hunting. The sow is calm, does not react to the boar. The duration of the dormant period is 9-10 days, sometimes up to 14 days.
