Heritability of susceptibility to cryptorchidism in swine

Abstract

Observations on 10 432 male pigs were used to evaluate the susceptibility of cryptorchidism in swine in relation to its heredity. Twenty-six (0.5%) Duroc-sired, 28 (1.3%) Landrace-sired and 14 (0.6%) York-sired, progeny manifested the defect. Differences in frequency of occurrence of cryptorchidism among progeny of the three boar breeds were highly significant (P<.001). Frequency differences among sires within breed of boar groups and age of dam effects, within boar breed groups, were not significant. Percentage cryptorchid pigs among male siblings of affected males for Duroc and Landrace groups, respectively, was 2.4 and 2.4 times greater than the overall percentage affected in their respective groups. Among Yorkshire-sired pigs, no litter had more than one affected animal. Heritability of susceptibility to cryptorchidism was calculated to be 0.21 + 0.19 and 0.28 + 0.18 in the Duroc and Landrace-sired groups, respectively.