4. Artificial insemination in goats

Artificial insemination (AI) is defined as the process by which sperm are collected from the male, processed, stored and artificially introduced into the reproductive tract of a female for the purpose of conception. It is essentially the most important techniques for genetic improvement of farm animals. Although AI is most widely used for breeding dairy cattle, it is an indispensable tool for genetic improvement in small ruminants and poultry. AI has an interesting history; from the Arabian chieftain who introduced a wand of cotton into a mare's reproductive tract to collect semen in 1322 A.D., to Anthony van Leeuwenhook who first observed human spermatozoa under magnification, to Spallanzani who is described as the inventor of AI for successfully conducting AI in dogs and the Russian scientist Ivanoff who pioneered AI research in birds, horses, cattle and sheep, and was the first to successfully artificially inseminate cattle. Artificial insemination is and continues to be an essential reproductive technique for genetic purposes including creation and diffusion of genetic progress and conservation of genetic resources.

#### 4.1. Advantages and disadvantages of AI

mainly marketed as Sil-Oestrus® implant and Eazi-Breed® controlled internal drug release devices™ (CIDR) (Figure 1). Synthetic analogues are marketed as Chronogest® (Intervet, Angers, France) and Veramix sponges® (Pharmacia & Upjohn, Orangevillle, Canada). Traditionally, intravaginal sponges are inserted over periods of 9–21 days and in most cases, eCG or PGF2<sup>α</sup> is administered 2 days before at the end of pessaries removal. Factors that affect the success of an OS programme when progestagens are applied include species, breed, co-treatment, manage-

Figure 1. Some hormones used for estrus synchronization in goats. Hormones are mostly administered via the intramus-

The use of long-term progestagen treatments has been shown to result in lowered fertility rates in goats [22]. On the other hand, decreased periods of progestagen treatment may minimize vaginal discharge and infection, and increase fertility. Currently, short-term intravaginal progestagen treatment is advocated. Following withdrawal, does usually show overt oestrus within 48 h. More recently, an alternative means of supplying continuous, exogenous progesterone has been the CIDR's, developed for sheep and goats in New Zealand. It is made from medical

ment, stage of the oestrus cycle, duration of treatment and mating system.

cular, intravaginal, oral or intradermal route (picture by B.O. Omontese).

134 Goat Science

AI has several advantages of which the greatest is the ability to maximize superior sires for genetic improvement. AI prevents spread or exposure of sires to infectious genital diseases. In addition, bull evaluation that accompanies AI enables early detection of infertile bulls, eliminated handling of stubborn bulls and allows use of bulls unable to mount due to foot injuries. Importantly AI also helps ensure that accurate breeding records can be kept. As with many scientific techniques, the disadvantages of AI include increased cost associated with labor and facilities. In addition, AI only allows utilization of a few sires, which reduces genetic base. Also, there is potential for rapid spread of undesirable traits, if bucks from which semen is sourced are not carefully evaluated, hence, if the buck had a genetic defect this will be widely spread in the population. Therefore optimum care and critical evaluation of semen from bucks to be used for artificial insemination is of paramount importance.

#### 4.2. Collection, extension and storage of semen

For AI to be successful, quality semen must be used. The quality of semen is determined by proper collection, extension and storage. Several methods of obtaining semen have been developed but the most popular method in goats is the use of electro ejaculator and artificial vagina. The later method, which gives the best quality, requires that the stud properly stimulated and then allowed to mount a teaser doe and ejaculates when the penis is directed into the artificial vagina. When an electroejaculator is used, rhythmic stimulation of the ampullae, accessory sex organs and the sacral nerve plexus cause erection and ejaculation. Semen should be evaluated for mass motility, individual progressive motility, volume, pH, ejaculate concentration and morphology. It is important that a strict sense of hygiene is maintained during the process of semen collection, processing and storage. Diluting/extending semen increases the volume and helps to increase the number of females serviced from one ejaculation as a normal ejaculate from a buck varies from 2 to 6.5 10 sperm/ml. Examples of commercially available semen extenders are sodium citrate diluent, Tris diluent, Cornell Union Extender, egg yolkphosphate [24]. Other non-conventional extenders include homogenized milk-fructose, homogenized whole milk-phosphate, Tris-coconut milk and coconut milk citrate [25]. Cryoprotectant glycerol, and antibiotics such as penicillin and streptomycin are added to semen extenders to inhibit bacterial growth [26]. Semen is stored for short term or long term depending on when it should be used. It can be refrigerated (+4C) for short term or in liquid nitrogen for long term (96C). Semen stored in liquid nitrogen can be viable for decades with limited deterioration in fertility.

Author details

References

2010;89:225-233

Bobwealth Oakina Omontese1,2\*

University, Shika-Zaria, Nigeria

of Minnesota, Saint Paul, MN, USA

Research. 1999;34:271-287

Animal Science. 2000;77:1-14

Research. 2005;60:95-11

225:600-6004

Small Ruminant Research. 2011;98:3-8

Reproduction Science. 2004;82:231-245

Sheep and Goats. Vol. 2. New York, USA: CABI; 1997

Pacific Journal of Reproduction. 2016;5(2):96-101

\*Address all correspondence to: drbobwealth@gmail.com

1 Artificial Insemination Unit, National Animal Production Research Institute, Ahmadu Bello

Estrus Synchronization and Artificial Insemination in Goats

http://dx.doi.org/10.5772/intechopen.74236

137

2 Department of Veterinary Population Medicine, College of Veterinary Medicine, University

[1] Ribeiro CA, Ribeiro ADS. Specialty products from goat milk. Small Ruminant Research.

[2] El Aich A, Waterhouse A. Small ruminants in environment conservation. Small Ruminant

[3] Dubeuf JP. The social and environmental challenges faced by goat and small livestock local activities: Present contribution of research—Development and stakes for the future.

[4] Omontese BO, Rekwot PI, Ate IU, Ayo JO, Kawu MU, Rwuaan JS, Nwannenna AI, Mustapha RA, Bello AA. An update on oestrus synchronisation of goats in Nigeria. Asian

[5] Wildeus S. Current concepts in synchronization of estrus: Sheep and goats. Journal of

[6] Holtz W. Recent developments in assisted reproduction in goats. Small Ruminant

[7] McCracken JA, Glew ME, Scaramuzzi RJ. Corpus luteum regression induced by prostaglandin F2-alpha. The Journal of Clinical Endocrinology and Metabolism. 1970;30:544-546

[8] Martin GB, Milton JT, Davidson RH, Banchero-Hunzicker GE, Lindsay DR, Blanche D. Natural methods for increasing reproductive efficiency in small ruminants. Animal

[9] Piper PJ, Vane JR, Wyllie JH. Inactivation of prostaglandins by the lungs. Nature. 1970;

[10] Abecia JA, Forcada F, Gonzalez-Bulnes A. Pharmaceutical control of reproduction in sheep and goats. Veterinary Clinics of North America: Food Animal Practice. 2011;27:67-79 [11] Gordon I. Controlled Reproduction in Farm Animals Series, Controlled Reproduction in

#### 4.3. Insemination technique

There are three methods of inseminating goats; intracervical, intrauterine (difficult), or laparoscopic insemination. For fertility to be optimum, semen must be deposited in the appropriate place in the reproductive tract of the female and at the right time (when a female is in estrus). In does, semen may be deposited in the vagina but the best location to optimize fertility is when semen is deposited in the inner cervix. Insemination in does requires the use of an insemination gun, pipette and vaginal speculum. AI guns are also referred to as pistolettes. There are three sizes of AI guns; 0.25 cc, 0.5 cc and Universal. A loaded AI gun consists of a plunger which forces a plug through the straw to expel semen, a barrel which houses the semen straw, disposable plastic sleeve (sock or sheath)—to keep the semen straw in place, semen straw and an O-ring-to maintain the inseminating sheath in place. Does must be restrained; vulva should be cleaned before inserting the inseminating gun. Semen should be slowly deposited near the uterine end of the cervix or just inside the uterus. The ease of inseminating goats varies, as it is simpler with older, multiparous does with larger and less convoluted cervix compared with younger does with smaller and highly convoluted cervix.

#### 5. Conclusion

Goats continue to provide of nutritional, economic and social benefits. Reproductive biotechnologies should be adopted to improve the overall efficiency of goat production systems. Estrus synchronization and artificial insemination continue to be essential reproductive techniques for genetic creation, diffusion and conservation of genetic resources.
