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1. the thick whitish fluid containing spermatozoa that is ejaculated from the male genital tract
2. another name for sperm



a thick, viscid, opalescent, and whitish fluid ejaculated during copulation by human males and males of other animal species. Constituents of semen are spermatozoa and seminal fluid.

Semen contains proteins (including enzymes and nucleopro-teins), lipids, carbohydrates, vitamins, prostaglandins, sodium salts, potassium salts, calcium salts, and other organic and inorganic substances. Semen production commences during puberty, reaches its peak at maturity, and diminishes toward old age. The quantity discharged varies from species to species. Men ejaculate 2–6 milliliters (ml), bulls an average of 4–5 ml, stallions 60–100 ml, boars as much as 250 ml, and rams 1–1.5 ml.

The potency of semen depends on the quality and quantity of spermatozoa. The quantity of spermatozoa in animal semen varies, totaling approximately 30 percent in rams, approximately 14 percent in bulls, and approximately 7–8 percent in boars and stallions. It may even vary in the same animal, depending on the animal’s conditions of existence. Seasonal secretion of semen is characteristic of most invertebrates and some vertebrates, including fish, amphibians, reptiles, and many birds and mammals. Some diseases are characterized by semen lacking (azoospermia) or deficient in spermatozoa (oligospermia) or by semen with spermatozoa that are motionless (necrospermia) or malformed (teratospermia).

Semen analyses are used in forensic medicine and in determining the causes of sterility. In agriculture, an appraisal of the quality of semen is important for the artificial insemination of farm animals, as are the methods used for diluting, storing, and transporting the semen.



The fluid that carries the male germ cells. Also known as seminal fluid.
References in periodicals archive ?
Mel DeJarnette, vice president of research and quality control for Select Sires, says, Amanda and Leah Marie have more than 25 years of combined experience in semen processing, cryopreservation and quality control under the guidance and mentorship of former laboratory manager, Roger Hanson.
Semen pH: Semen pH of Nili-Ravi buffalo bulls of Sahiwal and Bahawalpur districts was 6.
Dietary DHA enhanced motility of raw bull semen, however no affect on frozen-thawed semen (Gholami et al.
13, 2017, Jane Doe consumed the contaminated honey approximately every other day without knowing it contained the defendant's semen," they said.
Our search revealed that 27 viruses that can result in viremia have been found in human semen (Table).
Cryopreservation technique provides opportunity to preserve semen from the elite males and propagate the genome worldwide at economic conditions.
8) Semen analysis and characterization are the prerequisite to semen handling and artificial insemination.
Of those, 63 percent had Ebola fragments in their semen a year after recovering from the disease.
The report provides preliminary results from Liberia's Men's Health Screening Program (MHSP), the first national semen testing program for Ebola virus.
3) HIV and HCV can both pass from one sex partner to another in semen or blood, so people infected with one of these viruses often get infected with the other virus.
La criopreservacion de semen es un proceso fundamental para el desarrollo de biotecnologias reproductivas en equinos, dado que permite el transporte y el almacenamiento de semen a largo plazo (Loomis y Graham, 2008).
For aquaculture, cryopreservation techniques allow to maximize the use of the male, due to successive collections of semen during the breeding season, which increases the semen production per male.