Background and history

When pigs are found dead behind the sow they are usually recorded as stillbirths which may be wrong. They may have died after farrowing having breathed but died of chilling and hypoglycaemia.

Clinical signs

Piglets found dead behind the sow. They may be fresh or 3 - 4 days old.

Diagnosis

If the piglet dies before farrowing, it will show varying degrees of post-mortem or degenerative changes. A pig that dies during the process of farrowing or immediately afterwards will be fresh and normal. The two can be differentiated easily. The chest is opened and the lungs examined to determine whether the pig had breathed. The lungs of the true stillborn pig are a dark plum colour, showing none of the pink areas associated with breathing. Pigs that attempt to breath during the process of farrowing will show evidence of mucous obstructing the wind pipe. A good target level for stillbirths is 3 to 5 % of total pigs born. At this level there is no point in carrying out investigations because it is unlikely that external inputs can alter the situation. However once the level reaches beyond 7% it is worthwhile carrying out an investigation by records and post-mortem examinations.

Causes

• Stillbirths increase with the increasing age of the sow.
• Individual sows may be regular offenders and these can be identified by the sow litter card. The farrowing process should then be monitored.
• Stillbirths occur more in larger litters.
• Stillbirths are more common in pure breeds.
• Stillbirths are common in prolonged farrowings.
• Lack of exercise during pregnancy may raise stillbirth rates.
• Stillbirths are raised where there is a long gestation period.
• Farrowing house temperatures above 24?C (75?F) increase the risk of stillbirths.
• Uterine inertia results in stillbirths.
• High carbon monoxide levels in the air associated with faulty gas heaters can raise stillbirth rates significantly.
• Pigs found dead behind the sow can sometimes be related to particular farrowing crates in certain rooms and are due to draughts behind the sow.

An examination of records should clarify whether the problem is one of individual sows or across the herd.

Diseases of the sow which may result in stillbirths:-

• Anaemia.
• Aujeszky's disease.
• Eperythrozoonosis.
• Erysipelas.
• Leptospirosis.
• Mycotoxicosis.
• Parvovirus infection.
• PRRS.
• Toxoplasmosis (poisoning).

Treatment and management

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

• Age (or parity) profile of the herd.
• Sow number.
• Feed and amounts given.
• Clinical observations of the sow and any disease history.
• Parity
• Boar used during mating; date of service.
• Failure to come on heat.
• Date of abortion and condition of aborted piglets.
• 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.

Feed

• Increase feed intake from days 3 to 21 after mating.

Heat and light management

• The outdoor breeding female should always be derived from at least one pigmented parent.
• Provide extensive shades so that the sows can protect themselves from the sun.
• Site the arks in the wind direction so that with open ends cooling can take place.
• Provide extensive well-maintained wallows suitably sited so that sows do not have too far to reach them.

Contact with the boar

• Boar presence in the dry sow accommodation is recommended from the day of service through to the day of farrowing. The boar should be mixed in or have access to the group for at least the first 21 days of pregnancy. There is clear evidence that this will improve farrowing rates particularly if they are associated with summer infertility. If sows are individually housed the boar should be allowed to move down the passages and 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 practice home mixing and wet feeding are the tanks and pipes mould free?

Are you ever tempted to give feed to sows that has been slightly mouldy.

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?