Short Answer 
Semen consists of about 5% sperm and 95% fluids from various glands in the male reproductive system. Factors affecting semen volume include species, health, and fertility, with larger species generally producing more volume, such as pigs with hundreds of milliliters compared to humans’ 2-5 milliliters per ejaculation.
Step 1: Understand Semen Composition
The volume of semen is primarily a mixture of sperm and fluids produced by accessory glands in the male reproductive system. About 5% of the volume consists of sperm, while the rest is made up of fluids from the seminal vesicles, prostate gland, and bulbourethral gland. This composition is crucial for understanding the factors that influence semen volume.
Step 2: Assess Factors Influencing Semen Volume
Several elements can affect the amount of semen a male can ejaculate, including:
- Species: Different species have inherent differences in semen production.
- Health: A healthy male is likely to produce a higher volume of semen.
- Fertility: The male’s reproductive health and pedigree can influence semen output.
For instance, a well-nourished bull selected for breeding can provide a significantly higher quantity of semen compared to less healthy counterparts.
Step 3: Compare Species and Volume Differences
When it comes to the actual volume of semen, larger species usually tend to produce more. For example:
- Domestic pigs can ejaculate several hundred milliliters of semen.
- Humans typically have an ejaculate of only about two to five milliliters.
While size usually correlates with volume, individual characteristics like age, health, and reproductive strategies also play a significant role in these differences.