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Seasonal Infertility

Abortion means the premature expulsion of dead or non-viable foetuses. Embryo loss occurs when there is death of embryos followed by absorption, or expulsion. Healthy embryos grow into foetuses.

There is often alarm when an abortion is seen but it should be remembered that there can be loss of embryos at any time during early pregnancy, which often go unseen.

Embryo loss or abortion can be considered in three main groups:

  1. During the period from fertilisation to implantation
  2. During the period of implantation at around 14 days post-service to 35 days.
  3. During the period of maturation, which results in premature farrowings. It can be seen therefore that losses can take place at any stage from approximately 14 days after mating, when implantation has taken place, through to 110 days of pregnancy.

Records help to identify reproductive problems. These should include information on:

    - Age (or parity) profile of the herd.
    - Failure to come on heat.
    - Culling rates.
    - Bleeding and discharges from the vulva.
    - Repeats, sows not in pig.
    - Lameness.
    - Litter sizes.
    - Mastitis, lack of milk, swollen udders.
    - Deaths and their likely causes.
    - Poor conformation.
    - Prolapse of the vagina or rectum.
    - Savaging.

Symptoms

Piglets, Weaners & Growers
  • N/A
Sows
  • The delivery of a premature litter with or without mummified pigs.
  • Mucus, blood, pus discharges from the vulva.
  • Sow may be ill or normal.
  • Symptoms of a specific disease.
  • Sows not in pig.
  • Usually less than 2% of sows affected, however acute PRRS may cause rates to rise to 20% or more.

Causes / Contributing factors

Infectious Causes (common ones). Consider the following:
  • Aujeszky's disease.
  • Influenza virus.
  • PRRS (Blue ear disease).
  • Leptospira.
  • Specific bacteria, E. coli, klebsiella, streptococci, pseudomonas.
  • Parasite burdens.
  • Cystitis, nephritis.
Non Infectious Causes
  • Seasonal infertility.
  • Decreasing daylight length, poor lighting.
  • Low temperatures.
  • Chilling, draughts.
  • Poor nutrition.
  • Mouldy feeds.
  • Contaminated water.
  • Stress.
  • No boar contact.
  • Vaccine reaction.
  • Lameness.
  • Poor hygiene.

Diagnosis

Fresh, aborted foetuses should be submitted to a competent diagnostic laboratory where examinations can be carried out for evidence of viral and bacterial infections, together with histological examinations and toxic studies. In many cases the end results of post-mortem and serological tests do not identify any particular infectious organism, which may seem disappointing. However, it is useful in telling us what is not present.

A Checklist for Abortions

  • Abortion Level. Is this more than 1.5% of sows served? Take action.
  • Are sows ill? Probably disease.
  • Are sows otherwise normal? Probably non infectious, Maternal failures.
  • Is the problem seasonal? Autumn abortion syndrome.
  • Do they occur in a particular part of the farm? Environmental.
  • Are the aborted pigs fresh or alive? Suggests the environment.
  • Are mummified pigs present? Suggests infection.
  • Is the dry sow accommodation uncomfortable? Suggests the environment.
  • Are sow pens wet, draughty, poorly lit? Suggests the environment.
  • Does the ventilation system chill the sows? Suggests the environment.
  • Are there factors that place the sows in a negative energy state? e.g.: High chill factors, draughts, low feed intake, a change in bedding or availability.
  • Are sows short of food - Check feed intakes by volume and weight.
  • Is the food mouldy? Check for mouldy feed.
  • Do the sows experience 14 hours of good light at eye level?
  • Are the lights dirty, covered in fly dirt?
  • Can you read a newspaper in the darkest corner?
  • Do your sows have boar contact in pregnancy?
  • Are any other diseases evident in the sows? e.g.: lameness , cystitis, kidney infections.
  • Are the abortions associated with stress?
  • Increase feed intake from days 3 to 21 after mating according to body condition and environmental temperatures.
  • Increase the mating programme by 10-15% over the anticipated period of infertility.
  • Because boar semen can be affected, particularly by environmental temperatures, follow each natural mating 24 hours later by purchased AI.

Further Reading

Click on the links below to find out more about this disease, including treatment, management control and prevention information. The top link is the main article on this disease.