1. Replacement Sows Not in Estrus
Concept: When sows of the same age have already been in estrus more than twice, but the replacement sow still does not show signs of estrus, it is considered that the replacement sow is not in estrus. Generally, if the sow has reached a weight of over 100 kilograms or is older than 8 months but still does not exhibit estrus, it can also be classified as not in estrus.
Treatment Method: Move the sow to another pen or location, increase contact with a boar, and feed more green fodder. First, give an intramuscular injection of 5 ml VADE, then intramuscularly inject 1000 units of pregnant mare serum per sow.
Prognosis: Usually, over 80% of replacement sows will enter estrus and can be bred within 2-4 days after medication. Those that still do not show estrus are recommended for culling.
2. Adult Sows Not in Estrus
Concept: Adult sows that do not show estrus 12 days after weaning are considered sows not in estrus. This condition is generally caused by persistent corpus luteum, endometritis, or uterine suppuration. In some cases, embryos in pregnant sows may die at an early stage; in others, the sow's uterus may contain thick, viscous brown fluid or have a dead fetus or mummy. Treatment Method: For sows with endometritis or uterine suppuration, the uterus should first be washed (using Gongyan Kang). Follow method one, and additionally administer 0.2 mg cloprostenol. Sows not in estrus due to persistent corpus luteum should be given 0.2 mg cloprostenol to dissolve the corpus luteum and induce estrus.
3. Infertility in Sows After Long Breeding Intervals
Improper feeding and management of replacement sows, such as using feed intended for fattening pigs, can cause a mismatch in the development of body size and reproductive organs, leading to unsuccessful fertilization during breeding.Excessive nutrition in sows can result in obesity, with fat pressing on the fallopian tubes and preventing normal sperm-egg interaction during fertilization.
4. Improving Sow Conception Rate and Litter Size
During each estrus, the number of mature follicles developing on a sow’s ovaries is far greater than the number of piglets born. The main three physiological factors causing this difference are: failure to ovulate; delayed ovulation leading to fertilization failure; and implantation difficulties causing early embryonic death. Ovulation Inducing Hormone 3 (LHRH-A3) can stimulate the pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH), thereby promoting full maturation of the oocytes, increasing ovulation; synchronizing ovulation so that fertilized eggs are timely handled; and enhancing the activity of the fallopian tubes and uterus, making fertilization and implantation easier.It is recommended to administer a 25 microgram intramuscular injection of Ovulation Inducing Hormone 3 (LHRH-A3) at the time of breeding or 2-3 hours before.
Experimental data show that the average litter size per birth can generally increase by 1.5 piglets. A single artificial insemination combined with an LHRH-A3 injection can achieve the same effect as one natural mating plus one artificial insemination, or three artificial inseminations.
Improvement method: Inject human chorionic gonadotropin (HCG) 1000-2000 units intramuscularly in the mid-estrus to enhance estrus expression in sows and promote full follicle maturation; then administer a 25 microgram intramuscular injection of LHRH-A3 at the time of breeding.
5. Medication for Multiple Fetuses
After a sow becomes pregnant, if there is insufficient progesterone secretion from the corpus luteum or a history of habitual miscarriage, intramuscular injection of progesterone is usually considered, 50 milliliters each time, for a week, or HCG injection can be administered to help maintain the pregnancy.
6. Labor Induction (Daytime Farrowing)
Generally, over 70% of pregnant sows farrow at night, which increases the difficulty of work scheduling and the mortality rate of piglets. Therefore, daytime farrowing techniques for pregnant sows have been widely applied in many pig farms, especially overseas.
On day 112 or 113 of gestation, depending on the season and local temperature, intramuscular injection of cloprostenol (PG) at a dose of 0.1-0.2 mg can be administered at an appropriate hour. The drug takes effect within 24±2 hours, achieving daytime farrowing.
Advantages of medication:
1. Allows most sows to begin farrowing during normal working hours, reducing the occurrence of stillbirths.
2. Enables adjustment and cross-fostering of piglets between litters, enhancing the efficiency of sow nursing.
3. Produces more uniform piglets, thereby improving economic benefits.
4. Provides appropriate assistance for sows experiencing dystocia.
5. Facilitates unified management of piglets.