Comparative gross anatomy
| Species | Testis Wt. (grams) | % of Body Wt. | Orientation |
|---|---|---|---|
| bull | 300+ | .03 | vertical |
| ram | 250 | .3 | vertical |
| boar | 350 | .2 | oblique |
| stallion | 200 | .03 | horizontal |
| dog | 25 | .2 | oblique/horz. |
| cat | ---- | ---- | oblique |
| human | 25 | .03 | vertical |
| Species | Semial Vesicals | Prostate Body |
Prostate Disseminate |
Cowper's |
| bull | ++ | + | + | + |
| ram | + | - | + | ++ |
| boar | +++ | + | + | +++ |
| stallion | +++ | ++ | - (+) | + |
dog |
- | ++ | - | - |
| human | + | ++ | - | + |
| cat | - | ++ | - | ++ |
| Species | Seminal Vesicles | Prostate |
Cowper's |
| bull | No Clot Material | ||
| ram | No Clot Material | ||
| boar | Gel | ||
| stallion | Mucous | ||
| dog | No Clot Material | ||
| human | Clot | Clot Enzyme |
| Species | Sigmoid Flexure | Type | Erectile Tissue | Glans |
| 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 |
| Species | Speed of Erection | Ejaculate Time | Semen Volume | Sperm Concentration | Sperm Number |
| bull | rapid | short | medium | medium-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 Testis = high sperm numbers
Large accessory glands = large volume of the ejaculate with lower concentration
of sperm/ml