Artificial Insemination (AI)

Artificial insemination is a learned technique that, when performed with skill properly founded on knowledge, offers ease of use and a good level of success. However, results can be discouragingly poor for a technician lacking knowledge and the necessary attention to details needed for a successful outcome. Producers wishing to perform AI should seek out and attend a class instructing them on proper caprine insemination technique. A clinic offered by a reputable and knowledgeable company, organization, or university specializing in caprine artificial insemination should be attended. Classes that offer hands-on training with live animals, accompanied by in-depth lecture, will offer the maximum benefit for the beginning AI technician. Taking classes focusing on other species, although using similar techniques, often lack the details that determine future degrees of success when working specifically with goats.

A list of some companies specializing in caprine AI that offer on-location class instruction is at the end of this module.

Because AI techniques and methods are highly dependent on the variety of equipment employed, it is difficult to give a safe, step-by-step instruction to the producer without hands-on activity. However, for the purposes of this module a basic narrative is given on the procedures involved.

It is good to keep in mind that the success of any AI program is largely dependent on three primary factors:

  1. The use of live/viable fresh cooled or frozen semen.
  2. The appropriate timing of insemination in relation to estrus and ovulation.
  3. The proper deposition of semen in the doe.

Not every doe is a good AI candidate. Does who do not cycle normally every 17-24 days with regularity or who are difficult to determine when and if they are in estrus should be lesser candidates in a producer’s AI program.

A basic understanding of a doe’s reproductive anatomy is essential before beginning any attempt at AI. Externally, the doe’s anus and vulvar region are easily located. The vulva is the door to the vaginal cavity and consists of two vertical lips, or labia, located just below the anus. The vagina is a smooth-walled, soft, collapsed cavity. It acts as the connecting tunnel between the vulva and the cervix. A lubricated, narrow, and comfortably designed speculum can be used to open the smooth, muscular walls of the vagina. If inserted properly, following the slope of the doe’s rump, the speculum will naturally pass with ease into the fornix portion of the vagina. This area is where the buck would normally deposit semen during live copulation (natural service). Below this area and at the posterior end of the vaginal cavity, the os can be located with the use of a bright light. The light source selected by the technician is often a primary element in the success or failure of an AI attempt. The best lights are bright and ideally generate little to no heat. If the semen straw is exposed to any heat, cells in the vicinity of the heat source can be severely compromised. The light source should also attach securely to the vaginal speculum and be unobtrusive in design due to the limited viewing area. The os is the opening to the cervix and is the ultimate target for the AI gun’s entrance to the cervical rings. The cervix itself acts as the gateway to the uterus and is approximately one and one-half inches long. The cervix contains five cervical rings or folds with the os being the first.

The uterus, oviduct, and ovary

The os or opening to the cervix

Cervical vs trans-cervical artificial insemination

Cervical and trans-cervical AI are cost-effective, convenient, and less invasive methods of AI than are laparoscopic or intra-uterine procedures. When using a cervical technique for AI, semen is ultimately deposited in the cervix of the goat. With trans-cervical AI the techniques are similar, but the semen is deposited directly into the uterus. Both techniques eliminate the need to penetrate the abdominal cavity for access, or near access, to the uterus as is necessary with laparoscopic or intra-uterine AI. This then lessens the opportunity for any resulting infection.

Unlike AI in larger species, the goat due to its small frame cannot accommodate rectal entry to assist in traversing the cervix. In larger species such as the bovine (cow), equine (horse), etc., an arm can be inserted rectally to assist in manipulating the cervix as it is penetrated with an artificial insemination gun. In the goat, a lubricated speculum (accompanied by a light source) is used to open the vaginal cavity and thereby expose the cervix and os. The os, as mentioned, is the gateway to the uterus and is where the gun is ultimately inserted to deposit the semen.

Goat artificial insemination

Proper semen deposition in the doe’s reproductive tract

Knowing and determining the proper time to AI the doe is not only critical with regard to the condition of the spermatozoa and oocyte (egg) when they come in contact with one another, but also to facilitate proper placement of semen in the reproductive tract. Proper timing is necessary be achieved to allow the artificial insemination gun to partially penetrate and traverse the cervix prior to semen deposition. Any deposit of semen in the vestibule, anterior or fornix of the vagina is premature and incorrect. Additionally, depositing semen directly into the uterus is viewed by some to be incorrect and more invasive than necessary for the successful outcome of this procedure. Entering the uterus increases the potential for introduction of foreign microorganisms which could lead to infection. For this reason using sterile, individually wrapped sheaths as opposed to “bulk packs” (although slightly more expensive) is strongly recommended. Conducting a clean, and as near sterile a procedure as possible should be every technician’s habit.

A properly timed procedure should allow for relative ease in manipulating through the cervical rings. However, young or maiden does will prove markedly more difficult and are not advised for the beginning technician. Even well seasoned does, if stressed or made uncomfortable due to rough handling or poorly designed or ill-used equipment, can become so tense as to constrict the muscular canal of the cervix rendering its penetration past the os nearly, if not totally, impossible. It cannot be overstressed that AI should be performed with a slow, determined, but gentle approach with adequate time allowed to follow proper protocols.

Once the semen is properly deposited, it is believed that fresh semen can remain viable for over 12 hours in the doe’s reproductive tract. Processed and frozen semen is compromised to some degree and can be expected to have a somewhat shorter time of viability. Ovulation occurs just before or shortly following the end of the doe’s standing heat. It is also believed that the caprine oocyte will remain viable for approximately 12-24 hours post-ovulation. During natural service, this allows time for both the oocyte and the spermatozoa to fully mature. This maturation is needed to enable the zona pellucida, surrounding the ovum, to be penetrated by the spermatozoon.

Artificial insemination equipment and supplies

Some basic equipment is required for the producer to perform cervical and/or trans-cervical AI effectively. Ultimately the doe’s comfort should be in the forefront of the producer’s mind in the selection of tools to use.

Items can be purchased in the form of a kit with a substantial cost savings versus purchasing items individually. Kits differ in price between suppliers and in the quality of equipment they contain, and typically range from $115.00 to as high as $185.00. When comparing one company’s offering to another, keep in mind you often get what you pay for. It is good to become familiar with what should be found in a “complete” kit prior to making a purchase.

Look for the following when reviewing the various kits available:

  • Carrying case
    • A compact metal or plastic case for the safe and clean storage of AI equipment.
  • Kit warmer
    • While contained within the carrying case, pre-warms all AI equipment prior to its use.
  • Artificial insemination (AI) gun
    • A goat length (usually 12 inch) device used for the depositing of semen via a 0.25 or 0.5 cc straw; available in a variety of styles. Can be constructed for disposable use or constructed of metal for multiple applications.
  • AI gun sheaths
    • Disposable, sterile, individually wrapped outer plastic shells which fit over the gun providing a secure “seat” for the straw. Each AI gun requires a specific style of sheath to accommodate the guns specific design. Although not recommended, sheaths are available in “bulk packs” of 20-25 pieces.
  • AI light
    • A compact light source which should attach securely to the vaginal speculum. The most easily used light sources are independent of a battery pack, generate little to no heat, and are unobtrusive in design.
  • Vaginal speculum
    • When used in conjunction with a light source, enables the clear view of the cervical “os.”
  • Speculum brush
    • A soft brush, sized to provide thorough cleaning of the vaginal speculum.
  • Straw tweezers
    • Used for the retrieval of straws from both the liquid nitrogen tank, cane, and ultimately the goblet as well as the semen thaw unit’s water bath. Available in both 0.25 and 0.5 cc sizes.
  • Straw cutter
    • For proper seating in the AI gun sheath, this device delivers the critical square cut to the end of the semen straw.
  • Non-spermicidal, sterile lubricant
    • Used for the lubrication of the vaginal speculum prior to its insertion.
  • Semen thaw unit
    • A device designed for the proper control of the semen straw’s thawing process. The unit should be compact in design, providing optimal thermal protection, complete with a thermometer, and water and dry bath compartments.
  • Instruction booklet
    • A simple guide providing the technician with basic, introductory knowledge of AI concepts and techniques.
  • Insemination reports
    • Designed to assist in the maintenance of a “breeding diary” and the recording of pertinent data for each performed AI procedure.

Other items needed:

  • Fresh Cooled or Frozen Semen
    • Packaged in 0.25 or0 .5 cc straws and may occasionally be provided in glass ampules.
  • Vaginal Swabs
    • Used for the removal of excess mucus from the vaginal cavity.
  • Microscope
    • Of mid-grade or better quality with a tungsten or halogen light source and capabie of examining specimens at a minimum of 100x and 400x magnifications; used for basic thawed semen observations and analysis.
  • Microscope Slides
    • The platform on which the thawed semen sample is dispensed forviewing with the microscope.
  • Microscope Cover Slips
    • A small piece of plastic or glass used to cover the semen sample, allowing its proper viewing.
  • Liquid Nitrogen Storage Tank
    • Available in a variety of sizes, storage capacities, and duration of hold times; an over-sized thermos of a sort, to be filled with liquid nitrogen, for the long term cryogenic storage of both semen and embryos.
  • Liquid Nitrogen Tank Measure Stick
    • For the measuring and accurate monitoring of the volume of liquid nitrogen contained within the storage tank.

Laparoscopic/intra-uterine artificial insemination

The use of a laparoscope for the purpose of AI facilitates intra-uterine insemination. Because of its invasive nature, a licensed and trained veterinarian familiar with the technique and use of the laparoscope must perform this procedure. Despite its high cost, there are advantages of intra-uterine insemination versus cervical or trans-cervical AI methods; namely, above average rates of resulting fertilization and ultimate conception when proper technique, timing, equipment, and high quality semen are used. With this technique, the veterinarian is able to see the uterus through the abdominal cavity and deposits semen directly into the uterine lumen with an insemination pipette guided by the use of the laparoscope.

For 24-36 hours prior to the scheduled procedure, the doe must be denied food and water. The animal is then sedated and restrained in a ventral position, by use of a cradle, with the head pointed down. This positioning allows for the urinary bladder to fall away from the uterus. The doe’s abdomen is surgically clipped and prepared for aseptic surgery. Local anesthetics are administered in two locales where small incisions will be made. In one incision, the laparoscope is inserted via a cannula to see the uterus. In the second incision, another cannula is used to insert an insemination pipette with a special needle attached to the end, or an insemination gun fitted with an injection tip or aseptic needle. Each uterine horn receives a specified volume of spermatozoa. Once the semen is deposited, all equipment is removed and the puncture sites are stapled or sutured and dressed with an antibiotic ointment. The doe should then experience one to two hours of recovery in a quiet locale, undisturbed.

In vitro fertilization (IVF) and in vitro maturation (IVM)

Another form of fertilization can be accomplished with neither donor animal being present. This protocol involves the collection of spermatozoa from the buck and oocytes from the doe. Only recent achievements in goats have realized the fertilization of an oocyte in a culture dish housed in a controlled laboratory environment. Although new to the caprine industry, the use of in vitro fertilization has been explored with some success as an alternative to conventional cryogenic freezing of embryos. As practitioner techniques and levels of expertise become more accomplished, the use of fresh or frozen semen and oocytes for this procedure should produce regular, favorable, and successful results.

New technologies now afford some successful maturing of oocytes during both the breeding and non-breeding season of goats. Oocytes utilized in an IVF program are most often obtained from superovulated does via laparoscopic methods. The harvested, immature oocyte is washed in a Petri dish and incubated for over 24 hours in a tissue culture medium. Now an in vitro matured (IVM) oocyte, it is further incubated to prepare it for the fertilization process. Frozen semen is prepared for use by means of a process referred to as “sperm swim-up.” This process aids in the spermatozoa undergoing capacitation and in ultimate sperm selection. Once the spermatozoa and oocyte are properly prepared, they are incubated together for a 24-hour period during which time the spermatozoa set about the normal fertilization process. Resulting fertilized ova are then identified and closely monitored for their proper development over an extended period of time.

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