What are the causes of sows repeatedly failing to conceive after mating? How are they treated?
What are the causes of sows repeatedly failing to conceive after mating? How are they treated?
What are the causes of sows repeatedly failing to conceive after mating?
The causes of sows repeatedly failing to conceive after mating are mainly the following aspects:
1. Reproductive tract diseases. Caused by ovarian diseases, abnormal ovulation, improper timing of mating, inflammation of the reproductive tract, or decline of reproductive function. Inflammation of the reproductive tract is one of the main factors affecting the conception rate of sows. According to reports, more than 50% of cases of sows repeatedly failing to conceive after mating are caused by uterine inflammation. For example, inadequate disinfection during artificial insemination, damage to the birth canal caused by improper assistance during farrowing, or poor sanitation in the farrowing house, etc., all increase the probability of infection. In pig production, attention is usually drawn only when there are obvious clinical symptoms, while hidden endometritis is often ignored, and blind mating without any treatment will obviously lead to a decline in the conception rate, or even repeated failure to conceive after mating.
2. Sows being too fat. Because sows have a strong appetite, gain weight quickly, and are fed without restriction, the sow becomes too fat; the eggs and other reproductive organs are surrounded by a lot of fat, the sow ovulates less or does not ovulate, and the sow repeatedly fails to conceive after mating or does not come into estrus.
3. Infectious diseases. Infectious diseases such as parvovirus disease, atypical swine fever, Japanese encephalitis, brucellosis, porcine reproductive and respiratory syndrome, and streptococcosis;parasitic diseasessuch as toxoplasmosis and leptospirosis; and metabolic diseases such as protein deficiency, vitamin deficiency, and selenium deficiency, etc., can all cause repeated failure to conceive after mating, abortion, or stillbirth.
4. Aspergillus toxins. In recent years, clinical findings have shown that an important cause of sows repeatedly failing to conceive after mating is Aspergillus toxins, mainly the Aspergillus toxins produced by moldy and deteriorated corn, including aflatoxin, fumonisin, fusarium toxin, and gibberella toxin.
5. Non-sow factors. For example, if the boar used for mating has a low sperm count or poor sperm quality, it can also lead to sow infertility.
How are sows that repeatedly fail to conceive after mating treated?Treatment？
1. For sows with a normal estrous cycle but repeated failure to conceive after mating, especially sows returning to estrus 21 days or 25 days after mating, the following measures are recommended: perform uterine cleansing 2 to 4 hours before estrus mating. Dissolve 1.5 grams of penicillin in 20 milliliters of normal saline and inject it into the reproductive tract to purify the uterus, referred to as uterine cleansing. From 24 to 36 hours after the sow comes into estrus, inject 10 to 20 micrograms of LRH-A3 intramuscularly per sow, and 1 to 2 hours after injection, carry out two-step interval mating and insemination, with an interval of 4 to 8 hours between the two times. This method can bring the sow conception rate to 95.23%. Sows that still fail to conceive after treatment with drug uterine cleansing and LRH-A3, as well as those with declining reproductive function that have lost breeding value, should be culled in a timely manner.
2. Antibiotic treatment of sow infertility caused by ovarian cysts: if the sow has irregular estrus or no estrus, or continues to be in estrus but repeatedly fails to conceive after mating, with swelling and enlargement of the labia and frequent discharge of mucus from the vulva, etc., luteinizing hormone can be used, injected intramuscularly at 50 to 100 units per sow, or chorionic gonadotropin injected intramuscularly at 500 to 1000 units per sow.
3. For multiparous sows in estrus, within 1 to 2 hours before timely insemination, use an insemination tube to directly inject 900,000 to 1,800,000 international units of erythromycin into the sow's uterus, and only then inseminate the sow, with medication used once per insemination. The sow pregnancy rate can reach more than 92%.
4. For sows with ovarian dysfunction but a strong physique, normal estrus, normal vaginal secretions, and overall good health. A modified Siwu Tang can be used: 10 grams of angelica, 10 grams of prepared rehmannia, 10 grams of red peony root, 8 grams of actinolite, 8 grams of psoralea, 5 grams of goji berry, and 15 grams of cyperus rotundus. Decoct in water 3 times, 1 dose per day, mix with feed and administer, and taking the medicine for 3 consecutive doses from 2 to 5 days before the next estrus mating can cure it.
What are the methods of mating sows?
There are 3 methods of mating sows, namely natural mating, manually assisted mating, and artificial insemination, etc.
1. Natural mating. Let the boar and sow mate directly. Normally the boar and sow are raised separately. When the sow comes into estrus, select a boar that meets the plan and drive them together to the mating pen, let them complete mating automatically, and then drive them back to their original pens. This method is relatively simple, but mating hygiene and mating results are not very good.
2. Manually assisted mating. This refers to the method in which, when the boar and sow mate, the reproductive organs of the boar and sow are disinfected, and necessary auxiliary measures are taken to help the boar complete mating smoothly. This mating method allows strict selection and mating, is conducive to breed improvement, expands the utilization rate of breeding boars, controls the number of matings by breeding boars, and extends the service life of breeding boars. When carrying out manually assisted mating, the selected breeding boar and the sow in estrus should be driven to the mating pen, and it should be done 2 hours before or after feeding the boar and sow. First wipe around the sow's vulva and around the boar's prepuce with a 0.1% potassium permanganate aqueous solution, then wipe once more with clean water. After the boar mounts the rear of the sow, pull the sow's tail to one side, hold the penis inside the boar's prepuce with the other hand, and guide the penis naturally into the sow's vagina, then observe the boar's thrusting to judge whether the boar has ejaculated and how long the ejaculation lasts. After the boar and sow finish mating, slap the sow's rump to make it contract suddenly and prevent backflow of semen. During manually assisted mating, the body type and weight of the boar and sow should be fairly similar, so as to facilitate smooth mating. After mating is completed, mating records should be made in a timely manner as the basis for correct feeding and management in the next stage. The breeder performing assisted mating should stand beside the sow near the rear end, moving position as the boar and sow advance and retreat, ensuring that they are not bumped or stepped on by the boar and sow, and can help the boar and sow complete mating smoothly.
3. Artificial insemination. It is the most widely used, most effective, and most economical mating method, and is one of the most effectivetechnicalmeasures for accelerating the development of the pig industry.