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.
Symptoms
Piglets
- Found dead behind the sow. They may be fresh or 3 – 4 days old.
Causes / Contributing factors
- 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).
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.