Inheritance of porcine stress syndrome

A total of 66 litters were farrowed in a Yorkshire herd of pigs selected for porcine stress syndrome (PSS) susceptibility. These litters included all possible combinations of matings between stress-susceptible, stress-carrier, and stress-resistant animals. When the data were analyzed by within-litter chi-square analysis, the null hypothesis of recessive inheritance could not be rejected (P less than 0.05). In addition, when the data were analyzed across litters, the null hypothesis of autosomal recessive inheritance could not be rejected (P less than 0.05).