Plasma CPK as an Indicator of Stress Susceptibility in Swine

A total of 18 pigs from litters in which one or more littermates died from stress were used to study the effect of sampling technique and exercise on plasma creatine phosphokinase (CPK). Plasma CPK in stress susceptible pigs was compared to CPK concentration in 7 control pigs with no history of stress. Plasma CPK was similar in samples obtained from cannulae and first and second samples obtained via puncture of the anterior vena cava. This suggests that blood samples can be obtained by a variety of methods for CPK determination if care is used in the collection procedure. Stress susceptible pigs had higher CPK values than control pigs and the CPK increase following exercise was much greater in stress susceptible than in control pigs. Plasma CPK after exercise increased to more than 100 sigma units/ml in 41% of the stress susceptible pigs, reaching maximum concentrations by 8 hours after exercise. These studies indicate that if blood CPK is used as an indicator of stress susceptibility, differences between susceptible and non-susceptible pigs can be greatly magnified by a standard exercise prior to samplings. There was no significant difference in transmission values among the control pigs, stress susceptible pigs with high CPK or the stress susceptible pigs with low CPK. However, stress-susceptible pigs tended to have higher transmission values.