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Back Muscle Necrosis

(253) 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.

Clinical signs

The onset is sudden with severe pain in the lumber muscles with obvious swellings. The pig is reluctant to stand and often adopts a dog sitting position. As the name implies there are muscle changes and death (necrosis) of muscle fibres with haemorrhages into the tissues themselves. The disease is relatively uncommon. It is usually initiated by sudden movement and is sometimes seen when maiden gilts are released from confinement to outdoor accommodation.


There is a history of sudden lameness associated with movement and acute pain. 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. The temperature is usually normal but may be elevated.

Similar diseases

These include:

  • Acute erysipelas.
  • Fractures.
  • Mycoplasma arthritis.
  • Leg weakness (OCD).
  • Spinal damage.
  • Inject with phenylbutazone 1ml/50kg or other pain killer.
  • Inject with corticosteroids provided the animal is not pregnant.
  • If there is a temperature give an injection of long-acting penicillin to cover the possibility of erysipelas.
Management control and prevention
  • Breed from pigs that are free of the stress gene.

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