E/LMS 12603: How to Collect and Store Semen

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Semen is most commonly collected from bulls in bull studs using an artificial vagina, as described below. Electro ejaculation is an alternative method used with bulls that cannot mount or are too fractious for easy handling (e.g. range bulls). Finally, semen can be collected by the message of the seminal vesicles and ampulla per rectum.

There are three commonly used techniques for collecting semen: the 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 (AVs 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 for using an AV are that the male is 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 depend on his species and temperament.

Females can be used, but unless they are in oestrus, 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.

Digital Manipulation

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 oestrus 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 ampulla (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 catheter, one can obtain a sterile ejaculate using this technique.

Semen is collected routinely from chickens and turkeys using a form of digital manipulation.

Electro Ejaculation

Electro ejaculation 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 anaesthesia in many species.

Electro ejaculation 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 anaesthetized prior to the procedure.

Another advantage of electroejaculation is that it does not require a mounted 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 incapable of mounting due to musculoskeletal disease or injury. It is used for collecting semen from quadriplegic or paraplegic 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 electro ejaculator usually have a larger volume (due to excessive accessory gland secretion) and a lower number of sperms.

Three pieces of equipment are required for electroejaculation. The electro ejaculator 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 electro ejaculator 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 minimise 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.

Semen Collection via Artificial Vagina

Semen collection from bulls using an AV requires three people: one to handle the teaser animal, one to control the bull and one to collect the semen. It is important that the collection area have non-slip flooring to avoid injuries and because ejaculation may be inhibited if the bull is nervous about his footing. Bulls are heavy and should have regular hoof care. Poor hoof condition can inhibit the bull from mounting or cause pain when dismounting.

A steer is most commonly used as a teaser and mount animal. Female teasers are not recommended because of the potential risk of intromission and the spreading of venereal disease. The teaser should be a calm animal of the appropriate size for the bull being collected.

The back and rear quarters of the teaser are washed with a disinfectant every collection day. It is also common for the rear quarters to be clipped routinely. The bull's preputial hair should be clipped in preparation for using the AV. These sanitary precautions are intended to minimise microbial contamination of the semen collected.

For collection, the teaser is positioned straight in front of the bull for mounting. Oftentimes, it helps to arouse the bull if the steer is led around the collection arena with the bull behind, then stopped abruptly, similar to the behaviour of a cow in oestrus.

The artificial vaginal (pictured above) uses thermal and mechanical stimulation to stimulate ejaculation. The liner of the AV is filled with water at 42-48 degrees Celsius, and the inner surface is lubricated with something like K-Y jelly. An insulating cone is placed over the end from which the collection tube protrudes to avoid subjecting the semen to temperature shock.

False mounting is an effective way to sexually stimulate the bull. Providing two false mounts with two minutes of active restraint and one additional false mount maximises sperm cell numbers. Final preparations are made to the AV between the second and third false mounts. Proper construction of the AV is important to avoid damaging the bull's penis and avoid stressing sperm cells.

Successful semen collection with an AV depends on the bull being comfortable around people, and they need to be trained to use the AV. However, bulls are big and dangerous, and personnel safety should be emphasized constantly. Most bulls in artificial insemination centres have a nose ring installed as a valuable and humane means of physical control. Bulls undergoing semen collection should be haltered and one should never tie a bull up by their nose ring - if startled, then can rip it out which is not only quite traumatic but yields an animal that may be exceptionally difficult to control. During collection, the person handling the AV must remain aware of where their feet are relative to the bull. As the animal ejaculates, it is common for him to jump forward. To avoid foot injury, collectors should wear boots with steel toes.

In artificial insemination centres, bulls are typically collected 2 or 3 times per week, with 2 or 3 ejaculates per collection day. The following images depict a routine semen collection from a bull.