- Necrotic changes are very often accompanied by bleeding, most likely the result of injuries and/or ear biting (cannibalism). The disease most often affects the auricles of both ears, in some cases limited to the tip of the ear, and in others it affects its edge.
- Eventually, most pigs' ears heal, but the process depends on the extent of the lesions. Mild lesions dry up, forming black scabs, which then completely disappear and heal, often without leaving any visible consequences.
- More serious lesions and those complicated by biting take longer to heal and most often result in the loss of part of the auricle.
Epidemiology
The above description concerns a health disorder called porcine ear necrosis (PEN), which is a quite common, yet mysterious disease occurring in pig production around the world. This problem occurs mainly in countries with intensive pig production; cases of ear necrosis have also been reported in Poland. The disease mainly affects piglets from the first to seventh week of life, and is most often observed in pigs approximately two weeks after weaning. Ear necrosis may affect up to 80%. pigs in a group. In practice, very large differences in the occurrence of the disease were recorded within one farm, not only between subsequent groups of weaned piglets, but also between individual pens containing pigs weaned at the same time. These observations are also confirmed by data from pig farms in the USA, where cases of ear necrosis appear unexpectedly and sporadically. However, they differ in terms of morbidity, severity of lesions and overall impact on pig productivity on farm. Other studies have shown that mild lesions (scabs) do not negatively impact animals' weight gain.
