Caprine Method - Artificial Insemination

Why Use AI?

Artificial Insemination is an excellent herd management tool. When used in conjunction with the knowledge of the sire development programs, you are able to use bucks far superior than you may find in your own immediate area for natural service. You may break into a genetic pool from a bloodline that has long since been dead, as semen can be stored indefinitely in liquid nitrogen. Breeding to improve certain traits in your own herd, you are able to advance much more quickly by using AI than by using only one or two bloodlines in natural service.

Generally speaking, a buck is not a long-lived animal. His personal goal is to develop quickly, servicing as many does in his lifetime as possible. He very well may be deceased by the time his progeny are mature enough to notice his fine traits. By collecting the semen, and keeping it stored properly, years later, this buck may still be useful in an AI program.

The custom collection companies are professionals who are skilled at handling bucks, semen and equipment necessary to store it long-term. Their procedures are such that, the quality of semen is usually excellent, and little worry over this aspect of AI should occur. Most companies offer tips and guidelines as well as backgrounds on the bucks they offer. Most publish a catalog of buck listings in all breeds as well as the supplies needed to complete your artifical insemination needs.

Candidates for Successful AI

Obviously, does that have been inseminated artificially before are strong candidates. Older does that have never been serviced by AI may not be good, as their cervix may have become scarred or bent from previous kiddings. Some will reject the procedure violently! Yearling does that have never been mounted by a buck are especially good candidates. Usually, if you can successfully AI a young doe, she will be a strong candidate the rest of her reproductive life. Small does may take a small speculum, and you have to experiment with sizes on these. AI is especially good here because a young doe may be inseminated who may be still too small for natural service.

To be successful in an AI program, you need to begin to collect the materials and order semen long before the breeding season begins. Choose the females you wish to AI and begin watching them for heat detection early in the fall. The weather plays a big part on their cycle, however. If it is a cool damp summer, very likely natural breeding can occur as early as July or August. Strong heat cycles mean easy detection, and better chances of being on target when you AI. September and October are optimal months for breeding, with heats becoming less pronounced later in the season.

Some work has been done to successfully AI does out of the traditional breeding season by using hormones, and when I learn more may have a future article on that topic. Ideally, you should know the timing of your AI candidates, from the time she begins to show interest in the buck pen to the latent heat stages. Keep in mind this will change with each doe, and even with the different heats she has as the season progresses.

The best method of checking for cycle stage is the flow and condition of the mucus discharge. Some does will only have a slight external discharge at the onset of heat, and a speculum will be needed to detect conditions inside her vulva. Normally, once you notice a doe flagging her tail in all outward signs of heat, (pen mates riding her, general activity concerning that doe), you will concur she is approaching standing heat. This is when the doe will allow the buck to mount, if serviced by natural methods. Over the course of the cycle, she will allow breeding several times, with generous amounts of semen being deposited each time.

When you use AI for breeding, the amount of live sperm in each straw is small compared to natural service. This is why your technique must differ greatly from the buck's. The AI technician must actually deposit semen directly into the cervix, not in the vaginal canal outside it, as does the buck. Knowing the correct time of penetration is the key to a successful AI program. This and correct handling of the frozen semen are the two most important factors in the whole process.

After you have observed the heat cycles of the AI candidates, you can now chart her progress toward the next cycle. Clip her tail, keeping the long hair cut short as well as any superflous hair around her vulva. A variety of speculum sizes and shapes should be on hand. A speculum is nothing more than a clear glass shell, open on both ends. One end has a contoured shape to the opening so it fits closely against the cervix. These may be of pvc plastics or Pyrex. The smaller the doe, of course, the smaller size needed to fit reasonably comfortably, making sure there is still enough room to work.

A slender light, sold for AI purposes is necessary to put inside the speculum to check mucus flow as well as aid in inserting the AI gun into the cervix. Some homemade lights have been adapted from egg candling devices but make sure the lighting device you choose does not offer any heat at all.

The gun itself may be one of three types; most preferred is the gun called the 'new' French AI gun. This has a needle attachment on the end which is approximately the length of most caprine cervixes. The needle is slightly flexible to allow easier penetration. Plastic sheaths and needles are necessary; all can be obtained separately. The older goat gun is simply a smaller version of the gun used to inseminate cattle. Some people learn by using the cattle gun, and find it easier to use. Both are rigid metal guns with plastic sheaths covering the length of the gun.

AI lubricant is necessary to help ease the speculum inside the doe, and a number of brands are on the market for this purpose. Cattle AI technicians generally will dilute the lubricant to about 2 parts water to 2 part lubricant in a clean squirt bottle. In goat insemination, the amount and frequency used makes this an unnecessary step. The kind of lubricant used may act as an agent in clouding the mucus discharge, giving the technician a false reading, if unaware of this. Knowing what to look for inside the doe is the key to knowing when and where to insert the gun.

The exterior flesh of the vulva does not show sign of heat until spread slightly. Applying a light pressure to press the vulva apart, the walls should be bright pink. Mucus discharge should be beginning to cloud slightly and become thicker. A very copious, clear mucus discharge is an indication that the doe is not ready for inseminating at this time. The time can vary from 12 hours to even 48 hours later, so it is wise to check often. If you notice the discharge has become thick and pasty, she has advanced too far into the heat cycle to be inseminated. This is the beginning of the mucus plug her body forms after each heat cycle to protect the cervix.

Using your AI light inside the speculum, you should notice the end of the cervix to be very red. Some people describe this appearance as that of a 'rosebud' or similar to a small wad of pink bubblegum. If the red condition becomes paler, fading to soft pink, the doe is going out of heat cycle. The opening of the cervix will appear as a black dot, somewhat off center from the visible red of the cervix. Usually, the dark spot can be found "between 5 o'clock and 7 o'clock", but it will vary with each doe, and even as she moves around, the cervix entrance can relocate.

Actual AI Method

NOTE: Do not attempt to thaw semen until you have located the cervix in the doe.

Begin by having all the materials and the liquid nitrogen tank at the worksite. Have the doe in a headstall restraint if possible. Two people working together is ideal, but one can do it alone if necessary. Select the canister the desired semen is in, and reattach it so that particular canister is in the neck of the working area of your nitrogen tank.

Note the name of the buck on the cane and straw. A water bath to thaw the straw is necessary. Some elaborate straw thaw jars are on the market, but a dependable thermos bottle will work. Place the AI light inside the speculum which should be in place in the doe's vulva already. Keeping the straw at 98 degrees Farenheit for 30 seconds is vital.

Taking the straw from the cane with tweezers and setting it into the thermos, be careful the remainder of canes remain below the frostline in the nitrogen tank. Using a timer or watch, count the 30 seconds. Have the AI gun body warmed or rub briskly between warm hands to warm the metal.

You may now use your fingers to remove the straw from the warm water, wiping the excess water from the straw with a paper towel. Keep the straw out of direct sunlight or drafts at all times. Recheck the ID of the straw before actual insemination begins once again.

Insert the straw into the gun, always keeping the top of the straw pointed out, or up. Before inserting completely, use a straw cutter and carefully clip the end of the straw. This must be done in a perfect straight line, as an improper cut may result in semen leaking out around the straw before it can be utilized. If using the French gun, fix the needle on the end of the gun and attach a sheath to cover the gun. Keep the gun near your own body temperature to keep temperatures from fluctuating and damaging the now active sperm.

Wipe the gun and needle lightly with an alcohol-soaked pad before entering the doe. Wipe the doe's exterior vulva and base of her tail with a baby-wipe as well. Enter, pushing the plunger slightly to expel a bit of semen to the top of the gun, allowing some to act as interior lubricant.

Gently push the tip of the gun into the dark spot, feeling for bands of strictures as you move the gun. There are 5 rings inside the small cervix that need to be penetrated before you are 'on target'. You may have to move the tip of the gun around until you can feel the needle passing through each ring. You may not be able to pass the tip of the gun through all 5 rings.

Push the plunger a bit to eject semen gently into each ring. Sometimes this acts as enough lubricant to allow the gun to travel further into the cervix. Many times the doe will become restless and move at this critical point, pushing the gun away from the targeted area. Attempt to go as far as possible without damage to the doe or to the semen.

The last ring is smaller than the rest and you may never realize you have traveled through all 5 of them. If the gun suddenly feels like it is very easy to move forward, you possibly are entering the uterus. The cervix is a tough, almost abrasive, gritty organ and the uterus is a delicate, thin-walled body. You may cause some damage here if you persist in entering the uterus at this point.

Back the tip of the gun back, releasing semen very slowly as you retreat. (If you enter too far and deposit all the semen into one uterine horn, you could fail to have conception if the egg follicle travels to the opposite horn.) You could very easily deposit trace amounts of skin and material scraped from the vagina and cervix as the gun traveled through these tissues. This could cause infection if placed in the uterus.

When you feel you have reached the end of the cervix, you realize tissue structure has changed from coarse and gritty to soft and pliable, back the gun up, deposit the semen, and retreat from the cervix. To deposit the semen, do so slowly and carefully. Take your time! Remember, the gun and straw are warming comfortably inside the doe and the semen will remain at that temperature for the rest of it's short life. If you cannot get through a ring without difficulty, relax a moment, keeping the gun in it's current position. Continue until you feel you have reached target.

To deposit semen, push the plunger of the gun in very slowly. You are releasing live sperm which is easily damaged. The forward motion of the seminal fluid when pushed by the plunger will act as a guide for the direction the sperm must swim. If you are too gentle, and allow them to just flow out of the gun, they may never reach the uterus in time. If you are too forceful, you can easily break the tails off the sperm, causing them to swim around in confused little circles until they fade and die. A firm, gentle motion is all it takes to successfully eject the semen.

A bit of semen is always left in the tip of the gun, especially in the needle-type gun. It is wise to develop the practice of using this to make a slide to view on a microscope. By viewing after you have inseminated the doe, you have a good idea how strong the semen was while you were working with it, and what possible conception rate you might expect from this breeding. Experiment with the microscope, using 150x as the base. Make your slide very carefully, trying to avoid pushing the semen off to the edges, yet, not crushing the sperm when you place the top plate on the slide. If you see the sperm is actively swimming around, intact, and healthy, you can assume you have done a good job in this respect. If they are listless and/or still, you should assume 'operator error' in most instances. Improper technique in straw warming, handling the gun wrong, or other careless actions may be to blame.

There are many variables in Artificial Insemination. The doe must be in the correct phase of her heat cycle before you can begin to have success. The semen must have been of good quality and handled properly at all stages of the preparation. The AI technician must have skill and knowledge to correctly perform the methods described. If all of the above are met, the percent rate will still vary from 50% to 75% as being an adequately good rate of success.

Text and images copyright 1998 Martha Wells