Veterinary Andrology and Reproductive Techniques

EJACULATION

• The reflex expulsion of spermatozoa and seminal plasma from the male reproductive tract into female reproductive tract is called as ejaculation.
• The expulsion is the result of sensory stimulation of glanspenis.
• The sensory impulses are carried by the pudental nerves to the lumbosacral region.
• This results in firing of the nerves in spinal cord and forcing of the semen into urethra.
• All these activities will leads to emission (movement of seminal fluids from accessory sex glands into the pelvic urethra) and ejaculation.
• The emission occurs before ejaculation.
• In animals like boar, stallion and dog emission occurs in a sequence resulting in an ejaculate that consists of various fluid fractions.

Species	Volume of ejaculate	Site of deposition	Duration of copulation
Bovine	3-5 ml	Anterior vagina	1-3 sec
Equine	75-120 ml	External os of cervix	20-60 sec
Caprine/ovine	0.8-2 ml	Fornix vagina	1-2 sec
Swine	200-250 ml	Cervix and uterus	5-20 min
Dog	1-5 ml	Uterus	20-30 min

• The animals like bull, ram and stallion will ejaculate in short period of time and is called as short term copulators where as the boar and dog will take longer duration for ejaculation and is called as sustained copulators.
• In bull and ram the ejaculation is stimulated by warm temperature of the vagina.
• But in stallions and boar, the vaginal pressure is important when compared to temperature.

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