Topic 77. PSS (Porcine stress syndrome)- Metabolic Disease

Question 1

What is the background of PSS?

Answer 1

Genetic origin (ryanodine receptor mutation, homozygous recessive animals susceptible), pietrain and crossbreeds–

mutation produces lean meat in heterozygous animals

• selenium- and vitamin E deficiency might facilitate the process in weaners, fattening pigs and sows
• Overreaction to stress, abnormal amount of muscle contractions in response to normal impulses

Question 2

What is the basic forms of PSS?

Answer 2

Basic forms:

• sudden death (peracute)
• malignant hyperthermia
• back muscle necrosis
• PSE (pale soft exudative) meat

Sudden new stimulus (sunlight), moving, transportation can be triggers

Question 3

What are the Clinical Signs of PSS?

Answer 3

Clinical signs:

• sudden death: no previous clinical signs. Diff. diag: MHD, intestinal torsion, internal haemorrhage
• malignant hyperthermia: tremors, twitching face muscles, rapid breathing, skin reddened and blotched, body

temp. >41°C, death in 15-20 minutes, rigor mortis in 5 minutes (most specific sign)

• back muscle necrosis: localised form, stiff muscles, paresis, elevated plasma CK
• PSE: subclinical, serious lesions in meat – „pale soft exudative” meat, loss of value

Question 4

What is the treatment options for PSS?

Answer 4

Treatment:

• usually futile
• cooling with cold water, 50-100 ml Ca gluconate im. can be tried
• Screening for susceptible animals: halothane test (if available), genetic screening

Question 5

What is the Prevention of PSS?

Answer 5

Prevention:

• genetics:
• establishment of a herd free from the gene
• homozygous dominant animals to be bred with heterozygous ones to achieve high meat quality in

fattening pigs

• stress free environment
• Stresnil inj. (azaperone) before regrouping or transport
• Selenium and vitamin E supplementation