1. Porcine Stress Syndrome By Rushda Khan

2. Introduction Malignant hyperthermia Hypermetabolic syndrome
Pig highly susceptible to stress
Pietrain, Poland China, Duroc, Large White
Consequences for meat quality

3. Across species summary
Humans, pigs, cats, dogs and horses.
Dramatic rise in body temperature
Various symptoms
Volatile anaesthetics

4. Species summary and History
Transport or social stress
Hot weather
PSE meat
Humans: Unexplained anaesthetic deaths
First case in Australia in 1962 in humans

5. Clinical summary Muscular stiffness Tachycardia and tachypnea
Cardiotoxic serum potassium levels
Blanching and erythema
Elevated core body temperature

8. Generalized oedema and frothy exudates from trachea

9. Red skin (rash) Modern hybrid pigs
Show lesions of erythema when restrained.
Could die if not released quickly
Associated with stress susceptibility and PSS

10. Back Muscle Necrosis Special manifestation in animals > 50 kg’s.
Curvature of the body towards affected side

11. Pathology summary
Ryanodine receptor floods myoplasm of skeletal muscle with calcium
Muscle contracture and hypermetabolism
ATP depleted
Increased aerobic and anaerobic metabolism
Co2 and lactic acid produced
Rhabdomyolysis
Death occurs due to an increase in serum potassium
Cardiac dysrhythmia and arrest

12. Prevalence and Inheritance
Greater than 90 %
Higher in lean, heavily muscled breeds
Mortality around 3.2 %
Autosomal recessive gene with variable penetrance
Mutation in ryanodine receptor

13. Molecular genetics
At least 70 mutations in ryanodine receptor have been described
Long arm of 19th chromosome (19q13.1)
MH1 and 2 N-terminus
MH3 C-terminus

14. Genotype test and control
Use of halothane
DNA based assays
Select against trait
Economic consequences
Some breeds extinct
Good animal husbandry and management practices

15. Treatment Dantrolene sodium Fluid therapy Management of acidosis
Oxygen enrichment
Treatment of cardiac dysrhythmias
Unexplained anaesthetic or transport deaths

17. Consequences for meat quality
Unusually high rate of PM glycolysis
PSE meat
(Pale, soft, exudative)
Poor quality

18. References The Encyclopaedia of Animal Science
The Merck Veterinary Manual (9th edition)
Pig Production
A Colour Atlas on Diseases and Disorders of the Pig