Back muscle necrosis is part of the porcine stress syndrome and in affected pigs degenerative changes take place in the back muscles along each side of the spine. It is usually seen in the young growing gilt although occasionally it occurs in the adult female. The disease is relatively uncommon.
Symptoms
Growing Pigs and Gilts/Sows
- The symptoms are sudden in onset after exercise.
- Severe pain in the lumber muscles with obvious swellings.
- Incoordination.
- Death (necrosis) of muscle fibres with haemorrhages into the tissues themselves.
- Lameness – reluctance to stand.
- Adopt a dog sitting position.
- The temperature is usually normal but may be elevated.
- Discoloration of the skin over the affected area.
Piglets & Weaners
- N/A
Causes / Contributing factors
- Sudden movement e.g. from confinement to outdoor accommodation.
- Presence of the halothane gene.
Diagnosis
Based on the clinical signs. The pig can be made to stand with difficulty but there is no evidence of fractures. Examine the lumber muscles carefully, they will be swollen and painful on pressure. History includes sudden lameness associated with movement and acute pain.