What causes miscarriages in sows at each stage?
Miscarriages in sows at each stage -- what exactly causes them?
1. The sow shows no symptoms at all, but the litter size is small;
2. Return to estrus (early miscarriage).
Causes: stress, feeding management errors, nutritional causes (overfeeding), high temperature, etc.
2. Miscarriage occurring at any stage of pregnancy
1. The sow is emaciated, possibly with polyuria and excessive thirst; the aborted fetuses and placentas show no visible changes. Possible cause: nutritional cause -- insufficient feed intake.
2. The sow shows no obvious symptoms or no clinical symptoms, and miscarriage occurs at various stages of pregnancy.
Fetal autolysis or subcutaneous edema, visible abdominal effusion or hemorrhage, purulent placentitis. Possible cause: brucellosis.
Fetuses or placentas are nearly normal or somewhat autolyzed, edematous, purulent placentitis. Possible cause: uterine infection.
Fetal resorption, often with mummified fetuses, stillborn fetuses or weak piglets, and the decomposed placenta tightly wrapping the fetuses. Possible cause: parvovirus.
Fetuses show hydrocephalus, subcutaneous edema, pleural effusion, small hemorrhagic spots, and necrotic foci in the liver and spleen. Possible cause: Japanese encephalitis.
⟧ The sow has sneezing, coughing, anorexia, constipation, salivation, vomiting, neurological symptoms, etc.; delivers mummified fetuses, stillborn fetuses, fetal hepatic focal necrotic areas, or fetal resorption, necrotizing placentitis. Possible cause: pseudorabies.
4. The sow is extremely weak, lethargic, breathing with effort, coughing; fetal resorption or mummified fetuses, stillborn fetuses and weak piglets. Possible cause: swine influenza.
5. The sow is lethargic, anorexic, febrile, with conjunctivitis, vomiting, dyspnea, diarrhea, ataxia, convulsions; delivers mummified fetuses, stillborn fetuses, fetal edema, malformations, hemorrhage, and hypoplasia of the lungs and cerebellum. Possible cause: swine fever.
6. The sow is asymptomatic or shows elevated body temperature, miscarriage, stillborn fetuses, weak piglets, and occasionally mummified fetuses. Possible cause: swine toxoplasmosis.
3. Miscarriage occurring in the middle and late stages of pregnancy
1. The sow has mild symptoms, mild anorexia, fever, diarrhea, occasional miscarriage, diffuse placentitis, stillborn fetuses, weak piglets. Possible cause: swine leptospirosis.
2. The sow is anorexic or lethargic, miscarriage, stillborn fetuses, weak piglets, with no gross lesions. Possible cause: T2 toxin poisoning.
4. Miscarriage occurs at any time during pregnancy; when multiple sows miscarry, it mostly occurs at the same stage of pregnancy
1. The sow shows no symptoms at all, but it is relatively concentrated and seasonal, mostly occurring from September to November, and the fetuses and placentas often show no changes. Possible cause: seasonal miscarriage.
2. The sow has vesicles on the snout, mouth and coronary bands; the fetuses and placentas show no visible lesions. Possible cause: swine vesicular disease.
3. The sow is febrile, anorexic, lethargic, with patchy reddening of the skin, cyanosis; fetal necrotizing arteritis of the umbilical cord, edema. Possible cause: porcine reproductive and respiratory syndrome (blue ear disease).
4. The sow may be anorexic, febrile, depressed, rarely with corneal opacity, stillborn fetuses, mummified fetuses, miscarriage, fetal resorption. Possible cause: blue ear disease.
5. Systemic infection of the sow.
5. Miscarrying sows are from the same herd or the same age group
The sow shows no symptoms at all, with nutritional deficiency, management errors and other causes, stillborn fetuses or weak piglets, no cleft palate, small eyes, blindness, generalized edema. Possible cause: vitamin A deficiency.
6. Miscarriage as full-term stillbirth
1. Mummified fetuses, stillborn fetuses, low birth weight, malformations. Possible cause: anthelmintic poisoning.
2. The sow strains for more than 5 hours, especially with a large litter size or hot weather; the sow has pale mucous membranes, rapid breathing, and the fetuses and placentas often show no visible changes. Possible cause: fatigue, low hemoglobin level in the sow.
3. The sow is asymptomatic but it often occurs in cold seasons; the fetal tissues are bright red, and there is a large amount of serous bloody fluid in the thoracic cavity. Possible cause: carbon monoxide and carbon dioxide poisoning.
4. Farrowing in hot seasons, the sow pants, has congestion, trauma, etc., and the fetuses and placentas often show no changes. Possible cause: high ambient temperature, trauma.
7. Embryo implantation failure, reproductive disorders in the sow herd
The sow has vulvar swelling, edema, occasionally mammary swelling in first-parity sows, miscarriage, stillborn fetuses, weak piglets, and the fetuses show no visible lesions. Possible cause: zearalenone poisoning.
8. Preventive measures
1. After the sow conceives, give feed in sufficient quantity and of high quality according to the nutritional requirements of each stage of pregnancy; strictly prohibit feeding spoiled, frozen or toxic feed; feeding should be at fixed times and in fixed amounts to prevent overeating.
2. Give the sow plenty of drinking water and prevent excessive drinking.
3. During pregnancy, the sow must be protected from squeezing, collisions, falls, kicking, jumping, whipping and frightening, to reduce stress.
4. Keep the pen dry; keep it warm and protect against cold in winter, and cool it down and protect against heat in summer.
5. Select and mate reasonably, and prevent stealth mating, indiscriminate mating and inbreeding.
6. Carry out regular quarantine, preventive vaccination and deworming for sows to prevent diseases such as Japanese encephalitis and influenza.
7. Use health-care drugs for the long term or regularly to ensure normal farrowing in sows.
8. Use high-quality mold-removing products reasonably.
9. Sows with genetic defects and habitual miscarriage that cannot be cured must be resolutely culled.