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Artificial Insemination of Goats

Maria Lenira Leite-Browning, DVM

Extension Animal Scientist
Alabama A&M University


Introduction
The history of artificial insemination (AI) in farm animals began in the 1300s with Arabian horses. In 1780, Italian biologist Lazzaro Spallanzani performed his first AI procedure in sheep. Then in 1907, the veterinarian Elias Ivanov proved the viability of AI in reproduction when he opened a testicle of a dead, snow-frozen sheep and found live spermatozoids.

The technique became more viable during the decades of the 1940s and 1950s with the discovery of certain preservatives and research advances in sperm packing by cryobiologist Christopher Polge and his associates, Audrey Smith, Sir Alan Sterling Parkes, Nancy Phillips, and Glenn Salisbury. In 1957, the American Breeders Services, now known as ABS Global, improved their artificial insemination services by providing and distributing liquid nitrogen to farmers. This service turned AI into a viable option for cattle and small ruminant producers throughout the United States (US).

In goat production, this technique has been limited to mostly dairy goat herds. However, meat goat producers have shown interest in learning this technique to accelerate genetic gain in their herds.

Advantages of AI
AI is the best way to spread elite genetic material throughout a population. Semen can be collected from top bucks, frozen, and then transported throughout the world where it can be utilized by large populations to facilitate progeny testing. Progeny testing involves breeding offspring to determine their genetic merit.
AI helps producers to utilize their prize bucks that may be physically injured and unable to mate.
AI allows producers to increase their herds without purchasing and maintaining bucks or losing them to predators, injury, or illness.
AI is effective in controlling diseases.
AI is an important breed preservation process.
However, the success of any breeding program relies on good management practices. Before implementing an AI program, management practices should be evaluated and improved if necessary. The herd should test negative for caprine arthritis encephalitis (CAE), toxoplasmosis, chlamydiosis, Q fever, brucellosis, tuberculosis, and caseous lymphadenitis (CL). It is also wise to have effective control of gastrointestinal parasitism.

Artificial insemination can be performed in does showing spontaneous heat or estrus induction, or synchronization protocols by hormone treatments.

Disadvantages of AI
The technician must be well trained in the anatomy, function, and regulation of the doe reproductive tract to manipulate the reproductive function and estrus synchronization.
AI requires special equipment and facilities.
It requires a great deal of time to check heat that is crucial for a successful process. On average, a doe's heat phase lasts for 12 to 48 hours.
AI increases capacity to disseminate undesirable genes in a population.
Doe Reproductive Tract Anatomy and Physiology
The Doe's Estrous Cycle
The doe's estrous cycle is the interval between two estrus or heat periods that lasts an average of 21 days. The estrous cycle has four phases: estrus, metestrus, diestrus and proestrus.

The estrus or heat can last from 12 to 48 hours. During estrus does are receptive to being mounted by bucks. For artificial insemination, it is important to identify when a doe is in heat. Producers are encouraged to utilize teasers, usually a vasectomized buck to identify a doe in heat. The signs of a doe in heat are:

Swelling of the vagina
Seeking the buck
Standing for mating by the buck, teaser, or by other does
Frequent urination
Flagging tail
Vocalization
Presents vagina with mucus discharge that appears crystalline at the beginning, but may have a cheesy appearance near ovulation time.
When a doe is in heat
The heat is longer in does that have had multiple births (multiparous) than it is among yearlings or does that have never birthed (nulliparous). Ovulation occurs at the end of the heat phase or 30 to 36 hours after the onset of heat.
A well-nourished doe has a shorter estrus period compared to an undernourished doe. On occasions, a pregnant doe can show heat with or without ovulation.
A doe that expresses a prolonged heat may be experiencing problems such as ovarian cysts.
Does may also experience silent heat, which has no visible signs. Silent heat can go undetected by a producer. Does can experience false heat without ovulation.
The rate of ovulation increases with age. Does 2 to 5 years of age are more prolific than one-year-old does.
The metestrus phase lasts 2-3 days, occurring immediately after the estrus phase. Ovulation occurs 30-36 hours after the onset of heat. It is the period when luteinization occurs. Luteinization is the process of forming a corpus luteum, which is a yellow glandular mass in the ovary that secrets progesterone. During this phase the doe is no longer receptive to the buck.

Diestrus is the longest phase of the estrous cycle. Characterized by the functional corpus lutea, there is no sexual activity. The corpus lutea remains active producing progesterone up to 14 to 16 days. The number of corpus lutea present corresponds with the ovulations. In a non-pregnant doe the corpus lutea will regress under the action of prostaglandin-PGF2a secreted in the uterus.

Proestrus is the preparatory phase that lasts 2-3 days. It occurs when new follicles begin to grow and develop in the ovaries as the non-pregnant doe is about to return to estrus.

Preparing Does for Artificial Insemination
Does must be in good health status and have good condition scores. Check body condition. If needed, provide a good energy supplement for a 30-day period such as 1/2 lb/day of a high energy supplement with minerals and fresh water. Determine if does will be bred on normal or synchronized heat.

Estrous synchronization or induction:
There are several hormone protocols that have been recommended for estrous synchronization in goats: progesterone or prostaglandins F2 alpha (PGF2a). The choice and efficacy of the method depend on the season or time of the year. Prostaglandins works only if does have functional corpus luteum in the ovary. The utilization of hormones in estrous synchronization protocols are recommended during out of season or anestrous period. Note that in the US, the use of hormones in goats are under veterinarian supervision except when using the controlled internal drug-releasing device (CIDR).


Table 1. Protocols for Estrous Synchronization in Does Using CIDR Days & Time
Procedures
PROTOCOL ONE
Day 1 Insert CIDR in the vagina with device gun or applicator.
Day 7 or 17 Administer 1.5 cc (ml) of PGF2a intramuscularly.
Administer 2.9 cc (ml) of PG 600 intramuscularly.*
Day 8 or 18 Remove CIDR.

Introduce teaser in contact with the doe. Start checking heat, and inseminate doe once at 18 hours after the onset of heat, or inseminate 18 to 24 hours from onset of heat.

Alternatively
Remove CIDR and do AI by appointment 54 hours after removal of the CIDR.


PROTOCOL TWO
Day 1 Insert CIDR in the vagina with device gun or applicator.
Day 8 or 18 Remove CIDR.

Administer 1.5 cc of PGF2a and 2 cc of PG 600 intramuscularly.*

Introduce teaser in contact with the doe. Start checking heat, and inseminate doe once at 18 hours after the onset of heat, or inseminate 18 to 24 hours from onset of heat.

Alternatively
Remove CIDR and do AI by appointment 54 hours after removal of the CIDR.

* NOTE: PG 600 is a combination drug of 400 IU of Pregnant Mare Serum Gonadotropin (PMSG) and 200 IU of Human Chorionic Ganadotropin (HCG).


During the breeding season in the fall and winter, the CIDR can be applied to synchronize the heat of does without association to gonadotropin. For better efficacy of the method, keep doe in contact with the teaser from the moment of withdrawal of the CIDR until time of AI. This procedure will help the doe come in heat, increase ovulation rate, and help identify the moment of the onset of the heat.

Heat Check Schedule
To identify a doe in heat observe her behavior and examine the external genitals. Check heat twice a day, early in the morning and late afternoon.

Use a teaser such as a doe treated with estrogens or androgens, or a vasectomized, epididectomized, or a wethered buck treated with androgens. The teaser should be fitted with a harness marker. Once heat doe is identified, monitor the duration by placing the doe in a separate pen or barn in contact with the teaser. The time of the onset of the heat must be recorded.

The success of intrauterine AI in does depends on many variables:
The doe's reproductive soundness, general condition, and nutritional status.
The doe's cervix can facilitate the deposition of the semen in the uterus or transcervically. When frozen semen is applied, higher fertility rates occur when semen is deposited intrauterine.
In nulliparous does, the difficulties of bypassing the cervical os with the insemination gun to deposit semen is a factor that will influence lower pregnancy rates.
The method of estrous synchronization.
Timing and the number of AIs performed. The identification of a doe in heat is the most important factor for the success of the AI. A doe must be inseminated at least once within the first 18 hours after the onset of the heat. Timing is critical because the insemination process must be performed when the doe is still in heat, although ovulation occurs during metestrus. The alternative to heat checking is to perform AI by appointment 54 hours from withdrawal of CIDR. Although very convenient and less labor intensive, if it involves the use of frozen semen and yields a pregnancy rate of 35 to 50 percent.
The quality of the frozen, refrigerated, or fresh semen.
The expertise of the technician.
Compared to intrauterine AI, vaginal insemination can be performed with less concentrated semen when stored at room temperature. Does can be inseminated once during heat. This procedure can result in a 75 percent conception rate. Thus, vaginal insemination with fresh semen can generally be considered an easier method to apply in goats on a large scale. This will only work with fresh semen, not frozen semen.

Steps to Conduct Intrauterine AI in Does with Frozen Semen
Identify the doe in heat and certify the correct time for AI.
For a better access to the doe's cervical os, place doe in the stand, with the back legs up, raising its back and leaving its front legs in support and its neck and head toward the ground.
If needed, wash the doe's vulva with clean water to remove any dirt, and dry the area with a clean paper towel as seen in Figures 16 and 17.
Introduce the vaginal speculum and be sure to check for the appropriately-sized speculum. If needed, apply a nonspermicidal lubricant or petroleum jelly to facilitate the introduction of the speculum in the vagina. To introduce the speculum, open the labia of the vulva with one hand and with the other hand, gently introduce the thinner extremity of the speculum. As soon as it is introduced in the vagina, use a little pressure to orient the speculum toward and down to the vaginal floor. Use light source to visualize the cervical os. Be sure to distinguish the cervical os from the pleats of the vagina.
Examine mucus consistency and, if needed, remove excessive vaginal mucus with the speculum.
If it is time for AI ­ Determine which buck the doe should be inseminated to before thawing the semen.
Thaw the semen (see Figures 19 and 20). Prior to thawing the semen, use a thermometer to check for water temperature (95 to 98° F) before withdrawing the straw from the tank. Never lift a canister above the frost line of the tank. When the straw is removed with a forcep or tweezer from the tank it should be placed immediately in the thaw bath.
Do not expose semen to direct sun light.
Do not refreeze semen that has been thawed.
Remove straw from the tank for periods as brief as 5 seconds. If you cannot remove the straw at the first attempt, lower the caner back to the bottom of the tank for at least 30 seconds before trying again. Stay out of direct sunlight because ultraviolet light has a spermicidal effect that will kill the sperm cells.

Rapidly deposit the straw in the thaw bath to protect it from the sunlight.
Warm the barrel of the straw gun.
Dry the straw with a clean paper towel.
Cut the correct extremity of the straw or the opposite side of the cotton plug.
Insert straw into gun; be sure to protect the straw from the sunlight and extreme temperatures.
Place the plastic sheath over the gun barrel.
Return to the doe, introduce a clean vaginal speculum, and remove excess mucus.
Introduce the gun into the vagina to the direction of the cervical os, passing the gun through cervical rings until it reaches the uterine lumen, the interior of the uterus. If the operator encounters resistance in accessing the interior of the uterus, deposit the semen in the exterior of cervix, and make a note of this in your records.
Remove the gun speculum and leave the doe for a few minutes in the standing position before releasing her.
Observe if reflux of the semen to the gun occurred.
If possible, use a microscope to check for semen left in the straw. Check for sperm motility.
Release the doe from the AI stand gently.Record information from empty straw before discarding.
Keep records of the following:

Day and time of CIDR implantation
Day and time of heat detection
Date and time of AI
Technician
Doe and buck's ID by breed and name
Straw identification by date when semen was frozen and processor
Keep the liquid nitrogen tank in a fresh and secure location. To measure liquid nitrogen, use a piece of black metal rod long enough to hold and touch the bottom of the tank.

Dip the rod to the tank bottom and remove after 30 seconds.
Wave in the air until a white frost line appears on the rod. This line indicates the liquid nitrogen depth of the tank. Levels nearing 5'' require a refill.
Check nitrogen level once a week.
Wear thermal gloves and protective glasses when removing the straws from the tank.


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References

Bretzlaff, K. N., Nuti, L. C., Elmore, R. G., Meyers, S. A., Rugila, J. N., Brinsko, S. P., et al. (1992, June). Synchronization of estrus in dairy goats given norgestomet and estradiol valerate at various stages of the estrous cycle. American Journal of Veterinary Research, 53(6), 930-934.

Freitas, V.J., Baril, G., & Saumande, J. (1977). Estrus synchronization in dairy goats: use of fluorogestone acetate vaginal sponges or norgestomet ear implants. Animal Reproduction Science, 46(3-4), 237-244.

Freitas, V. J., Baril, G., Martin, G. B., & Saumande, J. (1977). Physiological limits to further improvement in the efficiency of oestrous synchronization in goats. Reproduction Fertility and Development, 9(5), 551-556.

Houdeau, E., Furstoss, V., Forgerit, Y., Bonné, J. L., & Leboeuf, B. (2008). Short-duration insemination with frozen semen increases fertility rate in nulliparous dairy goats. Animal, 2, 1496-1500.

Holtz, W., Sohnrey, B., Gerland, M., & Driancourt, M. A. (2008, April 15). Ovsynch synchronization and fixed-time insemination in goats. Theriogenology, 69(7), 785-792.

Leboeuf, B., Delgadillo, J. A., Manfredi, E., Piacère, A., Clément, V., Martin, P., et al. (2008, July). The cervix is the external entrance to the uterus which must be located and penetrated with the inseminating instrument. Reproduction of Domestic Animals, 43 Suppl( 2), 379-385.

López-Sebastian, A., González-Bulnes, A., Carrizosa, J. A., Urrutia, B., Díaz-Delfa, C., Santiago-Moreno, J., & Gómez-Brunet, A. (2008, March 15). New estrus synchronization and artificial insemination protocol for goats based on male exposure, progesterone and cloprostenol during the non-breeding season. Theriogenology, 69(5), 651.

Paulenz, H., Söderquist, L., Ådnøy, T., Soltun , K. , Sæther, P. A., Fjellsøy, K. R., & Andersen Berg, K. (2005). Effect of cervical and vaginal insemination with liquid semen stored at room temperature on fertility of goats. Animal Reproduction Science. 86(1-2), 109-117.

Pellicer-Rubio, M. T., Leboeuf, B., Bernelas, D., Forgerit, Y., Pougnard, J. L., Bonné, J. L., Senty, E., et al. (2007, November 29). High fertility using artificial insemination during deep anoestrus after induction and synchronisation of ovulatory activity by the "male effect" in lactating goats subjected to treatment with artificial long days and progestagens. Animal Reproduction Science, 109, (1-4), 172-188.

Resende, J. & Hlavinicka, M. (1990). Curso de inseminacao artificial em caprinos: Apostila. Escola de Medicina Veterinaria da Universidada Federal da Bahia, Brazil: 1-27.




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