Halothane sensitivity as a field test for stress-susceptibility in the pig

Abstract

ABSTRACTThe possible use of a pig's reaction to the anaesthetic halothane as a field test for Porcine Stress Syndrome in genetic improvement pro-grammes was investigated. A standard 3-min halothane test gave incidences of positive reaction of 20% in a composite Pietrain/Hampshire line, 5% in Norwegian Landrace, 1% in Hampshires and zero in Durocs, Large Whites and N. American Yorkshires. In the Pietrain/Hampshire population, two generations oftwo-way selection on the test gave a divergence in incidence of positive reaction of 85%, and the frequencies of affected progeny supported the hypothesis of monogenic recessive inheritance. From second tests made 20 days after the first, the probability of misclassifying a pig's reaction on one test was 5 ± 1%. Positive reactors had significantly shorter and leaner carcasses, fewer pigs born alive, poorer meat quality, higher mortality and greater plasma creatine phosphokinase activity than negative reactors.