Incidence and effects of epididymal stones on gonad indices in 3 groups of 15 broilers each of breeder grandparent, broiler breeder and indigenous roosters are described. Epididymal stones (ES) were found in the epididymis of all groups. The gonado somatic index, relative epididymal to testes weight, relative testicular volume to body weight, total daily sperm production of both testes, daily sperm production per gram body weight and extragonadal sperm reserves per rooster were affected causing decreased sperm production in testes. The findings showed that ES is highly prevalent in roosters and that there is no difference between industrial and indigenous flocks. A surprising finding was the presence of ES in indigenous roosters held for artificial insemination program in individual cages. The pathogenesis of ES in roosters is probably multifactorial but exacerbated by IBV, other pathogens and nutrition.
