title: Gonadal and extragonadal sperm reserves of the Brazilian Nelore zebu (Bos indicus).
abstract: Gonadal and extragonadal sperm reserves were estimated through hemocytometric method in six Nelore zebu bulls, aging 4-6 years, with normal spermatogenesis, and kept at sexual rest. Gonadal sperm reserve was estimated to be 47.8 +/- 5.8 X 10(6) sperm cells/g testis parenchyma and 9.8 +/- 1.7 X 10(9) sperm cells/testis. Using a time divisor of 4.94 days the daily sperm production was estimated to be 10.0 +/- 0.9 X 10(6) sperm cells/g testis parencyma/day and 2.0 +/- 0.3 X 10(9) sperm cells/testis/day. Epididymal sperm reserve amounted 11.9 +/- 1.6 X 10(9) spermatozoa/organ, distributed as follows: 35.3 +/- 3.6% in the head, 16.9 +/- 1.7% in the body and 47.7 +/- 3.7% in the tail.
mesh_terms: D000818:Animals; D001938:Brazil; D002417:Cattle / Q000033:anatomy & histology* / Q000502:physiology; D004822:Epididymis / Q000166:cytology*; D008297:Male; D009929:Organ Size; D013045:Species Specificity; D013076:Sperm Count; D013091:Spermatogenesis; D013094:Spermatozoa / Q000166:cytology*; D013737:Testis / Q000166:cytology*