Abortion and embryo loss in sows and gilts
Abortion means the premature expulsion of dead or non-viable foetuses. Embryo loss occurs when the death of an embryo occurs, followed by absorption or expulsion of the embryo.
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 farrowing.
Losses can take place at any stage from approximately 14 days after mating, when implantation has taken place, through to 110 days of pregnancy.
Clinical signs
Sow may show signs of illness (lethargy; inappetence; diarrhoea/scours) or may be completely normal.
Sows may show clinical signs of a specific disease, e.g. Classical swine fever or Erysipelas.
The delivery of a premature litter with or without mummified pigs.
Mucus, blood, pus discharges from the vulva.
Diagnosis
There are three parts to the investigations that must be carried out: first, collect information about the individual sows;
then request post mortem examinations and serological tests;
finally, assess the clinical evidence and feeding procedures in the herd.
Sow health history
It is important to study the herd history and environment. For example, is there a seasonal effect or an association with a particular area of the housing or management practice? You should also note the clinical state of the sow at the time of abortion. Does the sow show other clinical signs or is she apparently normal?
You should examine the aborted foetuses too. Are they fresh with no signs of any decomposition, .
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.
Causes
Infectious causes
Infectious agents can bring about abortion in three ways:
They can invade the placenta, cause inflammation (placentitis) and sometimes necrosis (tissue death), cutting off the nutrient and oxygen supply to the foetus.
They can invade the foetus and kill it.
The major infectious bacterial diseases which spread through herds and cause abortion are brucellosis and leptospirosis.
Examples of infectious diseases that can cause abortion:
Influenza virus.
PRRS (Blue ear disease).
PPV (porcine parvovirus
Leptospira./brucellosis
Specific bacteria, e.g. E. coli, klebsiella, streptococci, pseudomonas.
Parasite burdens.
Cystitis, nephritis.
Non-infectious causes
Seasonal infertility
Experiences have shown that 70% of all abortions fall into this category. Abortions, anoestrus and sows found not in pig commonly occur during the period of summer infertility when sunlight is intense and the weather is hot. Ultra violet radiation may also cause regression of the corpus luteum
Decreasing daylight length, poor lighting
To maintain a viable pregnancy requires constant daylight length. Ideally this should be 12-16 hours per day.
Low temperatures, chilling, draughts
Wet, damp environments or high air movement cause chilling and increase demands for energy. An important feature of environmental abortions is that the sow remains normal, often eating feed in the morning, and expelling the litter in the afternoon.
Poor nutrition
Mouldy feeds
Toxins from mouldy feed can cause abortions. The fungus can be at a low level in one of the feed constituents and barely detectable by visual examination and yet produce powerful toxins.
Stress
Bullying and fighting are often forgotten as predisposing factors of stress in individual sows.
No boar contact
The presence of the boar and his pheromones (male chemical hormones) . Pheromones are required to maintain pregnancy in individual susceptible disadvantaged sows.
Lameness
Lameness and pain, particularly from abscesses in the feet or leg weakness (osteochondrosis) can also cause the corpus luteum to regress due to stress.
Urinary tract infections
Low grade or chronic infections such as cystitis (infection of the bladder) and nephritis (infection of the kidneys) occasionally cause abortion.
Poor hygiene
Vaccine reaction
Contaminated water
Treatment and management
Increase feed intake from days 3 to 21 after mating.
Heat and light management
.
make social contact daily.
Increase the mating programme by 10-15% over the anticipated period of infertility.
Because boar semen can be affected follow each natural mating 24 hours later by purchased AI.
Mycotoxin management
Always check your feed bins. Are they water tight?
When were they last inspected internally?
Do they contain bridged mouldy feed?
Are the bins filled with warm feed?
Do you regularly treat the bins to prevent mould growth.
Are the bags of feed kept in a dry cool or wet warm place?
If you wet feed:
Do you check the roofs of your mixing tanks to see whether feed splashed on to them has gone mouldy.
Do you check the pipes?
Do you check the source materials?
Do you let liquid components of the mix sit around in hot weather in storage tanks?
Take care of the all above points to prevent abortions in sows and gilts
By-Dr Parvinder kaur
Veterinary officer
RDDL Jalandhar
9814652576
