Testicular Atrophy and Its Related Changes in Culled Boars: A Pathological Investigation

Abstract

Testicular atrophy is a major cause of culling in boars. Pathogenesis of this change is poorly understood. Therefore, we aimed to investigate pathological changes of the genital tracts of culled boars with testicular atrophy. Twenty-eight genital organs of culled boars collected from slaughter houses in Thailand were pathologically examined. According to testicular weight, the organs were allocated into 4 groups: severe atrophy (n = 12), moderate atrophy (n = 4), mild atrophy (n = 4), and normal control (n = 8). In the severe atrophic group, the mean weight of
atrophic testes (175.1 ± 51 g) was lower than those of the normal control boars (376.1 ± 72 g) (p < 0.001). By gross examination, 5 boars (42%) in the severe atrophic group had bilateral atrophic testes, but the remaining animals (58%) were unilaterally affected. Examination of cut surface revealed extensive fibrosis in those severe atrophic testes with less degree in the other groups. Microscopically, severe testicular fibrosis, severe degeneration and collapsed seminiferous tubules were frequently observed in those severe atrophic testes with frequently lymphocytic
infiltration. Fibrosis and degeneration were minimal in the remaining groups, and were absent in the control group. Examination of epididymides revealed sperm granulomas in the epididymal heads of severe atrophic testes (n = 2) and in mild atrophic testis (n = 1). No significant relationship between age of the boars and the occurrence of
testicular atrophy was found. In conclusion, severe fibrosis and degeneration were the most striking lesions in testicular atrophy. Allthough the causes of these changes remain unclear, our findings revealed useful information for clinical examinations of genital organs in boars.