1, feeding management factors
Sows are overweight and thin, lack of exercise, light and malnutrition (protein deficiency or amino acid imbalance, lack of vitamins and minerals, etc. ).
During the lactation of the first fetus, the reserve sow appears hyperlactation, which prolongs the recovery process of the sow uterus.
Without the corresponding stimulation of the boar, the boar can chase and climb or move to the fence near the boar fence. Generally, about half of sows have oestrus symptoms about 10 days after seed transfer.
Age and parity, sow age does not reach estrus, premature aging, that is, estrus or estrus is not obvious.
According to the observation of first mating weight, the number of first mating litters with the weight of 65,438+0.20 kg ~ 65,438+0.30 kg is relatively high, with less estrus after weaning and small mismatch interval. At this time, PMSG or PG-600 is injected on the day of weaning, and generally more than 80% of pigs are in estrus within 7 ~ 8 days.
2. Effects of Zearalenone (F-2 toxin) on sows.
Zearalenone (F-2 toxin) is mainly produced by Fusarium graminearum and exists in corn, wheat, sorghum and rice, which mainly harms the reproductive system of pigs.
Clinical symptoms: The clinical symptoms of swine F-2 toxin poisoning vary with exposure dose and pig age. ① Zearalenone can cause vaginitis, increased secretion, vulvar swelling and wig lesions before estrus in reserve sows; Breast development is premature, and the breast is enlarged; Retention of corpus luteum, no estrus. ② Postweaning sows showed delayed estrus, increased estrus rate, abnormal estrus, repeated infertility or pseudopregnancy; Long-term feeding will cause ovarian atrophy, estrus stop or estrus cycle extension. Early embryo death or fetal malformation of pregnant sows leads to abortion, stillbirth and litter size reduction (litter size can be reduced by 0.8 ~ 1.5), and rectal, vaginal and uterine prolapse is serious. ③ The feed intake and milk yield of lactating sows decreased, and weaned piglets were light in weight, difficult to raise and low in disease resistance. After weaning, the estrus of sows is delayed, the mating rate is not ideal, and some sows are repeatedly infertile; The conception rate can be reduced by about 12%, and the service life of sows is short. The sow follicle degenerates, the elimination rate is high and the service life is shortened.
Solution: Add advanced mildew remover to sow feed for a long time, because only good mildew remover can effectively adsorb mycotoxins and will not affect vitamins in feed, so there will be no reproductive obstacles caused by vitamin deficiency. It is suggested to use Zhongwei Newman Star and add 1 kg per ton of feed.
3. Endocrine abnormalities in sows.
Such as ovarian cysts and persistent corpus luteum. The sick sow with follicular cyst is obese and the estrous cycle is disordered. Individual pigs have long-term supernormal, frequent, irregular and persistent estrus, reaching 7 days ~ 10 days (Xiong Mu mania). The vulva of these pigs is congested and swollen, and they often discharge a lot of transparent mucus secretions, but some of them are often infertile or pregnant, but most of them are less than 7 litters. The incidence is mostly weaned piglets, and follicular cysts rarely occur in reserve pigs. A single cyst on one side may not interfere with the estrous cycle, and some may get pregnant, but the ovulation number and embryo survival rate of sows will be affected to varying degrees. The clinical manifestations of sick sows with corpus luteum cyst are lack of sexual desire, intermittent or long-term estrus, which is easy to be mistaken for pregnancy.
Pituitary luteinizing hormone (LH) for follicular cyst: Although it is a traditional medicine, it is still a good medicine for treating follicular cyst in practice. LH 100 IU ~ 200 IU for intramuscular injection, divided into 2 ~ 3 times. LH can be replaced by human chorionic gonadotropin at a dose of 500 IU ~ 1000 IU per head, with intramuscular injection for 2 ~ 3 times. LH or HCG can promote luteinization of cyst follicles. Injection of sodium cloprostenol/0/4 days after injection can eliminate the luteal phase in the sensitive period and promote the start of a new estrus cycle.
Prostaglandin (PGF2α) and its analogues can be used for corpus luteum cyst: PGF2α has a strong dissolving effect on corpus luteum. At present, the common PGF2α analogues in China are sodium cloprostenol (PG-CI) and oxytocin. 0. 1mg ~ 0.2mg/ head, propafenone 1 head.
4, infectious diseases and parasitic diseases
Many infectious diseases, such as swine fever, negative blue ear, brucellosis, salmonella, parvovirus, mycoplasma, chlamydia, Japanese encephalitis, trichomonas vaginalis, etc., can cause abortion, mummies, incomplete discharge of fetal membranes, and lead to long-term estrus after weaning.
Solution: Give sows regular health care to prevent diseases. Seven days a month, each ton of feed can be added with1000g of Zhongwei Yinqiao powder,125g of Miaolisu, 500g of Vipujian and 500g of Zhongwei Juxingxing. For pigs with abnormal estrus, 3000 g of Yabo, 500 g of Lihuning 1000 g of Zhongwei Junengxing can be added to each ton of feed for 7 days to 10, and the effect is obvious.
Of course, there are also some congenital factors: reproductive tract malformation, the fetus of this sow, developmental disorders, abnormal uterine development. This sow is generally not sexually mature or can not normally estrus; Ovarian hypoplasia, sows suffer from chronic respiratory diseases, chronic digestive diseases, parasitic diseases and so on. It is prone to ovarian hypoplasia, which leads to the inability to secrete enough hormones and cause estrus; Androgyny looks like a sow from the outside, but in fact, this "sow" has the gonad-testis of a boar, and these situations should be eliminated in time.