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.
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.
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:
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.
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.
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).
| Days & Time |
|
| 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. |
| 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 |
| * 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.
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.
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.
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.
Keep records of the following:
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.
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.
UNP-0095, February 2009, Maria Lenira Leite-Browning, DVM, Extension Animal Scientist, Alabama A&M University