Effect of scrotal streptothricosis on spermatogenesis in the bull

Cutaneous streptothricosis was observed in 171 (13.42 per cent) out of 1274 animals examined over a period of 12 months. Eighty-six (8.30 per cent) of the 1036 bulls examined had cutaneous and scrotal streptothricosis and 85 (35.71 per cent) of the 238 cows had cutaneous streptothricosis of varying degrees. More cattle were affected during the rainy and pre-dry seasons when the condition was more extensive and severe. Histologically, moderate testicular degeneration was observed in 15 (13.6 per cent) of 110 streptothricosis-free bulls and 14 (16.3 per cent) of the 86 bulls with scrotal streptothricosis. No correlation was found between scrotal streptothricosis and testicular degeneration and, or inflammation. Average percentage spermatogenesis was 89.7 per cent for normal bulls, 91.2 per cent and 89.5 per cent for bulls with mild and moderate scrotal streptothricosis respectively and 88.0 per cent for bulls with severe scrotal streptothricosis. Two chronic cases had an average percentage spermatogenesis of 89.0 per cent. There was no correlation between the degree and extent of scrotal streptothricosis and spermatogenesis. The slight increase in the thickness of the scrotum was not observed to affect the normal course of spermatogenesis.