This report from University of Winsconsin deals with the comparative diagram of the male reproductive system in domestiic animals and man.

1. Animal / Dairy Science 434
Comparative Male Anatomy

2. Testis
Species Testis Wt. % Of Orientation
(grams) Body Wt.
bull 300+ .03 vertical
ram 250 .3 vertical
boar 350 .2 oblique
stallion 200 .03 horizontal
dog 25 .2 oblique/horz.
rabbit 2.5 .1 vertical
human 25 .03 vertical

3. Reproductive
Organs of the
Bull
Cowpers
Gland
Caput Epididymis
Cauda EpididymisTestis
Scrotum
Glans
Penis
Bladder
Ampulla
Seminal Vesicles
Prostate
Rectum
Vas Deferens
Gubernaculum
Sigmoid
Flexure
Retractor
Penis
Muscle
Prepuce

4. Reproductive
Organs of the
Bull
Vertical

5. Ram
Vertical

6. Boar
Oblique

7. Anatomy of the Dog
Oblique to Horizontal

8. Stallion
Horizontal

9. Human
Vertical

10. Testis Orientation
Tail Head
Bull

11. Testis
Species Testis Wt. % Of Orientation
(grams) Body Wt.
bull 300+ .03 vertical
ram 250 .3 vertical
boar 350 .2 oblique
stallion 200 .03 horizontal
dog 25 .2 oblique/horizontal
rabbit 2.5 .1 vertical
human 25 .03 vertical

13. Ram
No Body of the Prostate
Ampulla
Seminal
Vesicles
Prostate
Bulbospongiosus
Muscle
Cowper’s
Gland
Bladder
Vas
Deferens
Pelvic
Urethral
Muscle

14. No Ampulla
Large Cowper’s
Seminal
Vesicles
Bulbospongiosus
Muscle
Cowper’s Gland
Vas
Deferens
Pelvic Urethral Muscle
Prostate

15. No Disseminate
Prostate
Seminal
Vesicles
Bulbospongiosus
Muscle
Cowper’s Gland
Vas Deferens
Pelvic Urethral Muscle
Prostate
Ampulla

16. Human
No Disseminate
Prostate

17. Anatomy of the Dog
No ampulla, seminal vesicles,
disseminate prostate or Cowper’s gland

18. Cat (Tom) Reproductive Tract
Prostate
Cowper’s Gland
Glans Penis
Corpus Cavernosum
Crus Penis
Vas Deferens
Ampulla
No Seminal Vesicles or Disseminate Prostate

19. Cat (Tom)
Reproductive
Tract
Note how close the
cowper’s gland is to the
penis in the cat.

20. Cat Glans Penis

21. Feline Anatomy:
Erection and
Mating

22. Accessory Glands
Species Seminal Prostate Cowper's
Vesicles body disseminate
bull ++ + + +
ram + - + ++
boar +++ + + +++
stallion +++ ++ - (+) +
dog - ++ - -
Cat - ++ - ++
human + ++ - +

23. Species Seminal Prostate Cowper's
Vesicles
Bull No Clot Material
Ram No Clot Material
Boar Gel
Stallion Mucous
Dog No Clot Material
Human Clot Clot-Enzyme
Accessory Gland Secretions

24. Penis Types
Muscular-Vascular Fibroelastic

25. Human Penis Cross Section
Corpus Cavernosum
Corpus Spongiosum
Urethra
Blood Vessels
Large VeinsMuscular-
Vascular
or
Fibroelastic?

26. Internal
Prepuce Raphe
Urethral
Process
Free End of Penis Glans
Penis
Filiform
Appendage
Bull
Ram
Boar
Stallion
Human
Cat
DogNo picture

27. Comparison of Penis Types

28. Human

29. Dog
Anatomy
Bulbus Glandis

30. Sigmoid Flexure
Bull
Boar
Fibroelastic Penis

31. Muscular-
Vascular
Penis Type
Stallion

32. The Penis
Species Sigmoid Type Erectile Glans
Flexure Tissue
Bull yes FE + Glans
Ram yes FE + Glans
Boar yes FE + not distinct
Stallion no MV +++ Large Glans
Dog no MV +++ Large Glans
Cat no MV +++ Large Glans+
Spines
Human no MV +++ Large Glans

33. Erection and Ejaculation Characteristics
Male Speed Ejac. Semen Sperm Sperm
Erection Time Vol. Conc. Num.
bull rapid short medium med.-high medium
ram rapid short small high medium
boar rapid long large low high
stallion slow moderate large low medium
dog slow long large low low
cat slow moderate small high low
human slow moderate medium low low
Large Testes = high sperm numbers
Large accessory glands = large volume of the ejaculate with lower
concentration of sperm

34. »Support
spermatogenesis
»Testosterone
synthesis
Primary
Spermatocyte
Sertoli Cells
Leydig Cells
Capillary
Basement
Membrane
Spermatids
Round Spermatids
Secondary
Spermatocyte
Myoid Cells
Seminiferous
Tubule
Spermatogonium

35. Seminiferous Tubules

36. Seminiferous Tubule

37. Sertoli CellSertoli Cell

38. Leydig Cell
Capillary
Interstitial Tissue (space)

39. Capillary
Leydig
Cells

41. Basal CellPrincipal Cell Stereo-Cillia
Epididymis

42. Cauda Epididymis near Vas Deferens

43. Vas Deferens
Smooth Muscle
Sperm