What are effective methods to promote estrus and ovulation in sows?
To enable sows to achieve multiple litters and high productivity, and to promote normal estrus and ovulation in sows that do not come into heat or that repeatedly fail to conceive after mating, the following artificial methods of inducing estrus can be used on the basis of strengthened feeding and management.
Boar-induced estrus
Use a boar in estrus to chase sows that have long failed to come into heat, or pen the boar and sows together in the same pen, so that the sows, through visual, olfactory and tactile stimulation, via nerve conduction, cause the pituitary gland to produce follicle-stimulating hormone, thereby inducing estrus and ovulation. Fresh boar semen, 50-200 ml, can also be injected into the sow's uterus to stimulate the genital mucosa and promote estrus and ovulation.
Foster-nursing of piglets or early weaning
If a relatively large number of sows farrow within a fairly concentrated period, then according to the specific situation, piglets born to sows with small litters or poor milk production can be foster-nursed by other sows, so that these sows no longer nurse piglets, which can bring them into estrus quickly. In addition, advancing the weaning time of piglets to 45 days or earlier and controlling the number of sucklings, so that the sow's udder becomes swollen from accumulated milk and the secretion of oxytocin is reduced, can bring sows rapidly into estrus and ovulation. The specific method is to train the piglets to start eating early; after the piglets begin eating, separate mother and young, gradually reduce the number of sucklings, and continue until weaning.
Changing pens and increasing exercise
Move sows that have long failed to come into heat to a new pen, and raise them together with sows that are still in estrus. Through mounting by sows in estrus, their estrus and ovulation are promoted. Strengthening exercise for sows, and practicing grazing and green-feed feeding, also help promote estrus.
Injection of pregnant mare serum
The serum of pregnant mares contains large amounts of placental gonadotropin, which can promote estrus and ovulation in sows and can also increase the conception rate. The method of use is subcutaneous injection, 5 ml each time, once daily, for two consecutive days.
Injection of chemically synthesized hormones
For sows that have long failed to come into heat, chemically synthesized hormones can be injected to promote their sexual desire and regulate reproductive function. For example, a single subcutaneous injection of 3 mg of diethylstilbestrol, or an intramuscular injection of 1-2 mg of 0.1% estradiol benzoate oil, or an intramuscular injection of 1000 IU of chorionic gonadotropin.
Chinese herbal medicine for inducing estrus
(1) Angelica sinensis 40 g, cinnamon 20 g, actinolite 40 g, Scrophularia ningpoensis 25 g, Eucommia ulmoides 25 g, fennel 25 g, prepared rehmannia 25 g, Ligusticum chuanxiong 20 g. Grind the medicines into powder and mix them into the feed for the pig to eat on its own.
(2) Angelica sinensis 75 g, Atractylodes macrocephala 50 g, Ligusticum chuanxiong 50 g, safflower 40 g, Epimedium 100 g, Massa Medicata Fermentata 100 g, decoct in water, with white liquor as the guiding agent, and take orally in three divided doses.
(3) Aged mugwort 250 g, Leonurus japonicus 500 g, Angelica sinensis 50 g, decoct in water and take.
(4) Chinese chives 100-150 g, brown sugar 150 g, mash them and mix with warm yellow rice wine and feed.
(5) Epimedium 50 g, water and yellow rice wine 150 ml each, decoct and take.
(6) Glutinous rice fried until it pops, feed 500 g per day, for several consecutive days.
(7) Saururus chinensis and the inner bark of camphor tree 50 g each, Lindera aggregata 250-500 g, add water, decoct and take.
(8) Grind white liquor yeast into fine powder, mix with liquor, then wrap it well with gauze, place it into the sow's vulva, tie an external string, and remove it after the vulva swells in 2-3 days.