If death occurs in early pregnancy a fully-formed mummified pig will be seen. A pig that dies during the process of farrowing or immediately afterwards will be fresh and normal. At this level there is no point in carrying out investigations because it is unlikely that external inputs can alter the situation. Individual sows can be identified by the sow litter card. The farrowing process should then be monitored.
Stillbirths occur more often in larger litters.
They are more common in pure breeds. Sows that have prolonged farrowings will have a higher number of stillbirths. Sows with uterine inertia and particularly if it is associated with calcium deficiency produce high numbers of stillbirths. One sow can make the average look bad. High carbon monoxide levels in the air associated with faulty gas heaters can raise stillbirth rates significantly.