Analysis of the Causes of Mummified Fetuses, Stillbirths and Abortions in Pregnant Sows

  1. Causes of mummified fetuses, stillbirths and abortions:

  (1) Poor egg quality or failure to breed at the right time causes the eggs to age prematurely; although fertilization may still barely occur, the embryos cannot develop normally and eventually die and are resorbed by the sow.

  (2) The feed for pregnant sows is not nutritionally complete, lacking the necessary protein, minerals and vitamins, especially calcium and phosphorus, as well as vitamin A and vitamin D, thus causing embryonic death.

  (3) Pregnant sows that are too fat or suffer from long-term constipation will have the normal development of the fetuses affected, thus causing mummified fetuses, stillbirths or abortion.

  (4) If moldy, spoiled, toxic or strongly irritating feed is given, it will cause feed poisoning and lead to abortion.

  (5) Mechanical stimulation, such as uneven ground in the exercise yard, ice, or driving the animals too hastily, can cause the sow to slip and fall. Narrow pen doors, crowding at entry and exit, and fright can all cause ab

  (6) A high degree of inbreeding often leads to an increased number of stillbirths, and sometimes also produces deformed or monstrous fetuses.

  (7) Disorders of hormone secretion in sows, high fever from minor illness, and diseases such as Japanese encephalitis, influenza and brucellosis can all cause stillbirths and abortion.

Pictured: sow

  2. Methods to prevent mummified fetuses, stillbirths and abortions:

  (1) Feed pregnant sows with a proper combined diet, maintain breeding condition, and ensure that the fetuses can obtain all the nutrition necessary for growth and development. Special attention should be paid to providing sufficient protein, minerals and vitamins, and to ensuring the quality of the protein.

  (2) Prevent feed poisoning: moldy grains, undetoxified cottonseed cake, rapeseed cake, potato stems and leaves, castor leaves, feed containing pesticide residues, overly acidic silage, starch slurry and starch residue, and distillers' grains with a high alcohol content should all be avoided as much as possible for feeding pregnant sows. Moldy or spoiled concentrate or mixed feed from the feed mill must also not be fed.

  (3) Pay attention to the management of pregnant sows: prevent all avoidable mechanical injuries such as crowding, biting and fighting, slipping and falling, whipping, fright and chasing, and sharp turns.

  (4) Avoid unnecessary and unplanned inbreeding as much as possible.

  (5) Do a good job of disease prevention and control, especially the prevention of diseases such as Japanese encephalitis and influenza, and treat diseases promptly when they are found.

  3. Preventing miscarriage and artificial abortion: During the gestation period of a sow, if before the normal farrowing time she is found to eat less or stop eating, behave abnormally, appear listless, have a red and swollen vulva with mucus discharge, and strain constantly, she may be about to abort. Immediately inject 15-25 mg of progesterone and administer a sedative orally to prevent miscarriage. If the farrowing date has been reached and there are signs of farrowing, with the udder swollen and secreting milk, but no fetal movement and no fetus delivered, while the abdomen gradually contracts, then the dead fetuses may have become mummified fetuses retained in the uterus. For such sows, artificial abortion should be adopted as early as possible to promote the complete expulsion of the dead fetuses; otherwise it will affect future reproduction. The simplest method is to inject 3-6 mL of oxytocin. There are also sows that did not undergo artificial abortion, or after artificial abortion no dead fetuses were seen to be expelled, yet after some time they came into estrus and conceived again. This may be because the abortion products were expelled while the keeper was absent and were eaten by the sow. It may also be a false appearance caused by endocrine disorders in the sow.