Ear necrosis in nursery pigs is caused by one or more of a combination of:
- unpalatable feed,
- no feed (feeders either left empty for some time or set too tight), or
- overcrowding (usually toward the end of the nursery feeding period).
One or more of these conditions, along with high humidity in the room, retard healing of ear suckling lesions because of secondary infection predisposed by the high humidity. Correct this by:
- never letting feeders go empty;
- adjusting feeders properly;
- feeding the correct diet;
- not letting nursery feed become stale;
- allowing at least 1 square foot of pen space per 25 lb (11 kg) bodyweight; and
- keeping the relative humidity below 50%.
Even though pigs may sneeze (from dust) and utility bills will be higher when the humidity is low, it is worth reducing humidity by increasing airflow. High humidity is a predisposing factor to greasy skin disease and pneumonia. In my opinion, the reduction in humidity is the reason wean-to-finish building pigs generally outperform conventionally housed nursery pigs.
--submitted by Ralph Vinson, DVM