There are three commonly-used techniques for collecting semen: use of an artificial vagina, digital manipulation, and electroejaculation. The technique used depends on the species being collected and the disposition of the individual male.
The Artificial Vagina
Artificial vaginas (AV's to the initiated) are used to collect semen from many species, most prominently cattle and horses, but also sheep, goats, rabbits and even cats.
Prerequisites to use of an AV are that the male be conscious, not significantly frightened of people, and more interested in ejaculating than in killing humans.
An AV uses thermal and mechanical stimulation to stimulate ejaculation. As shown in the image to the right, an AV is composed of a tube with an outer rubber lining that will hold water, into which is placed an inner liner that is lubricated just prior to use. The outer liner is filled and pressurized somewhat with water at 42-48 degrees Celsius. Shown below are AVs designed for use with bulls (bottom) and rabbits (top). The apparatus in the middle is a type of AV, usually called a director cone, which is used to collect semen from dogs.
To collect semen, the male is allowed to mount and the penis is diverted into the AV where he ejaculates. It is best to allow the male to thrust into the AV rather than trying to slide the AV onto the male's penis. What the male mounts depends on his species and temperment.
Females can be used, but unless they are in estrus, they rarely enjoy participating in the process, which can easily lead to injury of any and all of those involved. Another problem with using a female as a teaser is that if you miss with the AV, the female could be bred or possibly transmit venereal disease to the male. For collecting semen from bulls, a trained steer is usually used. In the case of stallions, a phantom ("dummy") is a popular choice for a mount.
Many males can be induced to ejaculate by applying pressure and massage to the penis. After the male becomes aroused, a director cone of some type, attached to a collection tube, is slipped over the penis to facilitate harvesting the semen.
This technique is commonly used for collecting semen from pigs and dogs. An initial training period can be helpful, and having a female in estrus to arouse the male often is useful, particularly when the male is shy.
Another type of message used occasionally with bulls is to stroke the ampullae (terminal vas deferens), seminal vesicles and prostate gland through the wall of the rectum; in almost all cases, the bull must be restrained standing in a chute and sedated to allow relaxation and extrusion of the penis. In conjunction with a urethral catether, one can obtain a sterile ejaculate using this technique.
Semen is collected routinely from chickens and turkeys using a form of digital manipulation.
Electroejaculation involves applying a series of short, low-voltage pulses of current to the pelvic nerves which are involved in the ejaculatory response. It sounds like an extremely unpleasant experience, but doesn't seem to cause much distress in bulls (although they do need to be securely restrained), and is conducted under anesthesia in many species.
Electroejaculation can be used with almost any mammal. With few exceptions, electroejaculation is the only technique useful for collecting semen from wild animals, in which case the male is anesthetized prior to the procedure.
Another advantage of electroejaculation is that it does not require a mount animal, and can be applied in the field using a battery-powered unit. Finally, electroejaculation can be used to obtain semen from animals that are physically incabable of mounting due to musculoskeletal disease or injury. It is used for collecting semen from quadrapelegic or parapelegic men who desire a child but cannot ejaculate due to spinal cord injury.
With bulls, where there is abundant experience collecting semen by both artificial vagina and electroejaculation, the samples collected using an electroejaculator usually have a larger volume (due to excessive accessory gland secretion) and a lower number of sperm.
Three pieces of equipment are required for electroejaculation. The electroejaculator itself is a power supply with rheostats to control the amplitude of the delivered current and lots of circuitry to prevent accidental electrocution. Second, one needs a collection tube, usually attached to a latex rubber cone ("loving cup") in which to collect the semen. Finally, the pulses of current are applied through an electroejaculator probe. The probe is inserted into the rectum such that the electrodes lie within the pelvic cavity.
Older probes had circular electrodes, which often caused undesirable muscle contractions; probes with parallel electrodes on one side minimize this problem. Three probes are shown below - the upper one is a commercial product for bulls and the lower probes were hand-made for use with small leopards (middle) and ferrets (bottom).
Successful electroejaculation of an animal demands skill. It is not simply a matter of punching buttons and turning knobs, but requires finesse in determining the proper timing and amplitude of pulses to apply to a given male.
|Index of: Collection and Evaluation of Semen|
|Introduction and Index||Overview of Semen Handling and Analysis|
Last updated on August 11, 2002
|Author: Melissa Rouge and R. Bowen|
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