**5. Artificial insemination**

Artificial insemination (AI) is an important technology for improving animal production. Through consistent use of AI, herd genetics can be advanced at a rapid rate. While AI is a technology that enables the dissemination of selected male genetics, embryo transfer (ET) is a technology that enables the dissemination of selected female genetics, and, by using ET, frozen embryos can be moved around the world at significantly reduced costs compared to movement of adult animals [37]. Utilization of either AI or ET requires careful doe management and is most effective when these technologies are used in conjunction with estrus or ovulation synchronization. Artificial insemination (AI) involves collection of semen from a buck and transfer of the semen to the reproductive tract of the doe. Does can be inseminated either with fresh semen or with commercially available frozen semen [38].

Other authors mention that AI allows producers to use superior bucks to dramatically improve performance of their herd [38]. However, the rewards of AI depend on sound management. Artificial insemination in goats is more difficult than it is in cattle because of the small size of the animal and the complex anatomy of the cervix, making insemination into the uterus difficult. Advantages of the AI are the following:

**1.** Genetic improvement via buck

sensitivity of the pituitary to negative feedback of estradiol, which causes an inhibition of GnRH release and therefore LH. Likewise, in sheep, it has been found that the feeding level determines the live weight and the body condition, presenting a static, dynamic, or acute effect of the nutrition on the ovulatory rate, which depends on the observed changes in live weight and body condition. The "acute effect" is the one that has been given more attention in current research to promote significant changes in follicular population and ovulation rate, without the need to present changes in live weight and body condition [34]. For the above, "flushing" overfeeding strategies have been used, which consist of increasing the energy or protein levels of the goats before and during the breeding, to positively affect the rate of ovulation and prolificacy. Alternatively, it is possible to maintain this nutritional practice 10–15 days after the breeding to contribute to the implantation of the embryo, reducing the early embryonic mortality. Recent studies confirm that goats with a body condition less than 3 respond better than others with greater body condition. Also, it is defined that the changes in the ovulatory rate that receive high levels of feeding positively affect a glucose increase at the cellular level. This implies that glucose participates in the control of ovarian function, where the levels are

regulated by insulin, which plays an important role in follicular growth in goats [35].

are felt using pressure [35].

96 Goat Science

tend not to respond to flushing.

**5. Artificial insemination**

However, assessment of body condition is a simple indicator of body fat reserves, which can be used by the goat in periods with high energy demand, stress, or undernutrition. Likewise, body condition values have been determined from 1 to 5, where 1 is skinny and 5 is obese. It has been evaluated that the goats must maintain a body condition of 3 so that the reproduction is not affected negatively; here, the visual aspect of the goat would be the backbone is not prominent, ribs are barely discernible, and an even layer of fat covers them. Intercostal spaces

Dairy goats with excessive fat reserves or over-condition at kidding may have a greater risk of lower milk yield and of increased health and reproductive disorders (see **Figure 1**), such as dystocia and fatty liver. According to Ref. [35], animals with extremely good body condition

Reproductive seasonality limits the reproductive efficiency in goat production systems. This seasonal reproductive pattern evolved in goats in a manner that time of parturition and lactation coincides with season of the greatest feed availability and favorable temperatures. In domestic goats, reproductive season starts between the summer and fall and ends between

Artificial insemination (AI) is an important technology for improving animal production. Through consistent use of AI, herd genetics can be advanced at a rapid rate. While AI is a technology that enables the dissemination of selected male genetics, embryo transfer (ET) is a technology that enables the dissemination of selected female genetics, and, by using ET, frozen embryos can be moved around the world at significantly reduced costs compared to movement of adult animals [37]. Utilization of either AI or ET requires careful doe management and is most effective when these technologies are used in conjunction with estrus or

the winter and spring, depending on both breed and geographic latitude [36].


The success of AI is dependent on:


#### **5.1. Techniques of artificial insemination**

#### *5.1.1. Artificial insemination transcervical*

The cervix of the doe has four tightly closed, cartilaginous rings that provide structure to the cervix and, along with cervical mucus, form a protective physical barrier against the entry of foreign particles. To achieve the highest pregnancy rates for AI, semen must be deposited into the uterine body or into each of the uterine horns. Deposition of semen into the uterus requires that all four cervical rings must be passed during the insemination procedure. The small size of the doe's reproductive tract, particularly for nulliparous (virgin) or young primiparous (once kidded) does, in addition to the tightness of the cervical rings and their typical lack of alignment, can make passing the insemination rod during transcervical AI a challenging task. However, several methods for transcervical insemination have been developed and are available [38], some of which are similar to procedures described for nonsurgical embryo transfer in goats [38].

#### *5.1.2. Standard AI method (tube speculum)*

The simplest transcervical AI method involves the use of a tubelike speculum and a standard French-style insemination gun. The speculum, with a detachable light, is inserted into the vaginal vault of the doe and used to visualize the external cervical which is the entry point into the cervical channel [39]. Frozen semen is available in 1/4cc or 1/2cc straws and must be appropriately thawed prior to use. Once the semen straw is prepared and placed into the insemination gun, a clean sheath is overlaid to protect the semen and reduce cross contamination between does. Sheaths can have either standard (rounded) or apex (pointed) ends that can aid in achieving deeper penetration of the cervix [40]. The insemination gun is introduced through the speculum, and the inseminator attempts to pass the insemination gun through the cervix and deposit the semen into the uterine body. Following insemination, the gun and speculum are removed and the speculum disinfected between does. The single-use AI gun sheath is disposed appropriately. The major advantage of the standard method is that it is a simple and easily mastered technique that is reasonably effective with older, multiparous does (see **Photo 1**). The major disadvantage of this technique is that it is difficult to pass the insemination gun through the small cervix of a young doe or through the cervix if it is highly convoluted. In many cases, the use of the standard technique results in deposition of the semen in the cervix if all the cervical rings cannot be passed. Under controlled conditions, pregnancy rates following the use of the standard technique are low, typically in the range of 20–30% [41–44].

the uterine body and individual uterine horn. To facilitate passage through the cervix, the doe's hindquarters are raised, and a Pozzi Tenaculum Forceps are used to grasp the cervix and align the cervical rings. Once the catheter is positioned into the uterine horn, the stylet is removed, and a small diameter insemination tubing is threaded through the urinary catheter and used to deposit fresh or frozen-thawed semen into the upper portion of the uterine horn. The urinary catheter is then repositioned into the opposite uterine horn, and the second half of the semen sample is deposited deep into that horn to complete the insemination. With trained technicians, the entire procedure takes about 5–10 min [41] and does not involve any surgical entry or anesthesia of the doe. Furthermore, pregnancy rates following deep cornual insemination were greater than those for laparoscopic insemination in their study. In a subsequent study, pregnancy rates using ovulation synchronization with TAI of a single dose of frozen semen were 58% and kidding rates similar at 53%. These pregnancy rates are comparable to those obtained for beef cattle for first-service insemination after TAI

Currently, artificial insemination techniques in goats and sheep have been limited globally due, among other factors, to the lack of economic resources and trained personnel. Currently, for every 10 cows that are inseminated, only 2 goats and 3 sheeps are inseminated. This low percentage of inseminated goats has caused that the genetic progress is limited in the caprine species. This technique is focused on the integration of high genetic quality flocks that allow them to use high-value semen and that can be used preliminarily in the programs of embryo transfer and in vitro fertilization [45]. One way of evaluating bucks is through their daughters. The fastest way is to use AI to have daughters in different flocks. To achieve this, it is necessary for producers to use AI to propagate genes from different bucks in their herds. Among the techniques of AI that have been used to increase the rate of conception is the technique of laparoscopy, which consists of the deposition of the semen directly inside the uterine horns, avoiding the natural barrier of the cervix (see **Photo 2**). With this technique, pregnancy rates of 80% with diluted fresh semen and 50–80% with frozen semen are achieved. First, the goat is given a water and food diet for 12 hours to reduce the contents of the bladder and rumen. This facilitates the location of the uterus and prevents regurgitation of ruminal contents. The ability of the inseminator will be the time it takes to deposit the semen in both uterine horns [45]. A highly trained technician can inseminate the goat in 2 minutes. Before initiating endoscopy, the goat is anesthetized locally with 5 ml (20 mg) 2% lidocaine hydrochloride subcutaneously (see **Photo 2**). Take special care to avoid injuring the blood vessels when injecting the anesthesia (see **Photo 3**). Local anesthesia aims to relax the goat and not present ruminant contractions and can visualize the uterine horns. Once the ventral cavity is pierced and in the direction of the nipples of the udder (10 cm of the

nipples), the endoscope is inserted (see **Photo 3**). The cavity is inflated with CO<sup>2</sup>

the localization and manipulation of the uterus. The insemination gun is inserted through the second puncture and inserted into the wall of the uterus into the lumen releasing the semen (see **Photo 3**). Usually, the semen is deposited in both uterine horns to achieve good results of pregnancy. Normally, both uterine horns are inseminated with the Aspic pistol

to facilitate

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using frozen semen [45].

*5.1.4. Artificial insemination by laparoscopy*

#### *5.1.3. Deep cornual (uterine) insemination (catheter-within-catheter) method*

In 2005, the development of a novel method for transcervical insemination of goats has been reported. In their method, semen is deposited deep into the uterine horn (cornua) by means of a catheter-within-catheter technique. This technique relies on the use of a soft, small diameter pediatric urinary catheter stiffened with an insemination gun stylet to enter

**Photo 1.** Student of agronomy practicing the transcervical artificial insemination in goats.

the uterine body and individual uterine horn. To facilitate passage through the cervix, the doe's hindquarters are raised, and a Pozzi Tenaculum Forceps are used to grasp the cervix and align the cervical rings. Once the catheter is positioned into the uterine horn, the stylet is removed, and a small diameter insemination tubing is threaded through the urinary catheter and used to deposit fresh or frozen-thawed semen into the upper portion of the uterine horn. The urinary catheter is then repositioned into the opposite uterine horn, and the second half of the semen sample is deposited deep into that horn to complete the insemination. With trained technicians, the entire procedure takes about 5–10 min [41] and does not involve any surgical entry or anesthesia of the doe. Furthermore, pregnancy rates following deep cornual insemination were greater than those for laparoscopic insemination in their study. In a subsequent study, pregnancy rates using ovulation synchronization with TAI of a single dose of frozen semen were 58% and kidding rates similar at 53%. These pregnancy rates are comparable to those obtained for beef cattle for first-service insemination after TAI using frozen semen [45].

#### *5.1.4. Artificial insemination by laparoscopy*

into the cervical channel [39]. Frozen semen is available in 1/4cc or 1/2cc straws and must be appropriately thawed prior to use. Once the semen straw is prepared and placed into the insemination gun, a clean sheath is overlaid to protect the semen and reduce cross contamination between does. Sheaths can have either standard (rounded) or apex (pointed) ends that can aid in achieving deeper penetration of the cervix [40]. The insemination gun is introduced through the speculum, and the inseminator attempts to pass the insemination gun through the cervix and deposit the semen into the uterine body. Following insemination, the gun and speculum are removed and the speculum disinfected between does. The single-use AI gun sheath is disposed appropriately. The major advantage of the standard method is that it is a simple and easily mastered technique that is reasonably effective with older, multiparous does (see **Photo 1**). The major disadvantage of this technique is that it is difficult to pass the insemination gun through the small cervix of a young doe or through the cervix if it is highly convoluted. In many cases, the use of the standard technique results in deposition of the semen in the cervix if all the cervical rings cannot be passed. Under controlled conditions, pregnancy rates following the use of the standard technique are low, typically in the range of

In 2005, the development of a novel method for transcervical insemination of goats has been reported. In their method, semen is deposited deep into the uterine horn (cornua) by means of a catheter-within-catheter technique. This technique relies on the use of a soft, small diameter pediatric urinary catheter stiffened with an insemination gun stylet to enter

*5.1.3. Deep cornual (uterine) insemination (catheter-within-catheter) method*

**Photo 1.** Student of agronomy practicing the transcervical artificial insemination in goats.

20–30% [41–44].

98 Goat Science

Currently, artificial insemination techniques in goats and sheep have been limited globally due, among other factors, to the lack of economic resources and trained personnel. Currently, for every 10 cows that are inseminated, only 2 goats and 3 sheeps are inseminated. This low percentage of inseminated goats has caused that the genetic progress is limited in the caprine species. This technique is focused on the integration of high genetic quality flocks that allow them to use high-value semen and that can be used preliminarily in the programs of embryo transfer and in vitro fertilization [45]. One way of evaluating bucks is through their daughters. The fastest way is to use AI to have daughters in different flocks. To achieve this, it is necessary for producers to use AI to propagate genes from different bucks in their herds. Among the techniques of AI that have been used to increase the rate of conception is the technique of laparoscopy, which consists of the deposition of the semen directly inside the uterine horns, avoiding the natural barrier of the cervix (see **Photo 2**). With this technique, pregnancy rates of 80% with diluted fresh semen and 50–80% with frozen semen are achieved. First, the goat is given a water and food diet for 12 hours to reduce the contents of the bladder and rumen. This facilitates the location of the uterus and prevents regurgitation of ruminal contents. The ability of the inseminator will be the time it takes to deposit the semen in both uterine horns [45]. A highly trained technician can inseminate the goat in 2 minutes. Before initiating endoscopy, the goat is anesthetized locally with 5 ml (20 mg) 2% lidocaine hydrochloride subcutaneously (see **Photo 2**). Take special care to avoid injuring the blood vessels when injecting the anesthesia (see **Photo 3**). Local anesthesia aims to relax the goat and not present ruminant contractions and can visualize the uterine horns. Once the ventral cavity is pierced and in the direction of the nipples of the udder (10 cm of the nipples), the endoscope is inserted (see **Photo 3**). The cavity is inflated with CO<sup>2</sup> to facilitate the localization and manipulation of the uterus. The insemination gun is inserted through the second puncture and inserted into the wall of the uterus into the lumen releasing the semen (see **Photo 3**). Usually, the semen is deposited in both uterine horns to achieve good results of pregnancy. Normally, both uterine horns are inseminated with the Aspic pistol

Once the artificial insemination is performed, the endoscope is removed, and a commercial disinfectant is placed in the incisions that were made. The amount of sperm deposited per dose varies from 40 to 100 million. The results of this AI technique will depend on other factors, including goats' body condition, insemination time, race, year time, and synchronization

Goat production globally has increased in recent years. Therefore, good reproductive strategies are required that are feasible to be applied by producers, such as the synchronization of estrus and ovulation, because it is required to have a more intense selection pressure via bucks (artificial insemination) as goats (embryo transfer and in vitro

\*, Alejandro Sergio del Bosque González<sup>2</sup>

1 Facultad de Agronomía, Laboratorio de Reproducción Animal, Universidad Autónoma de

3 Facultad de Agronomía, Laboratorio de Nutrición y Calidad de los Alimentos, Universidad

[1] Delgadillo JA, Duarte G, Flores JA, Vielma J, Hernandez H, Gonzalo FRG, Bedos M, Fernandez GI. Control of the sexual activity of goats without exogenous hormones: Use of photoperiod, male effect and nutrition. Tropical and Subtropical Agroecosystem.

[2] Delgadillo JA, Martin GB. Alternative methods for control of reproduction in small ruminants: A focus on the needs of grazing industries. Animal Frontiers. 2015;**5**:57-65.

[3] Fatet A, Pellicer-Rubio MA, Leboeuf B. Reproductive cycle of goats. Animal Reproduction

Science. 2011;**124**(3-4):211-219. DOI: 10.1016/j.anireprosci.2010.08.029

\*Address all correspondence to: fernando\_sd3@hotmail.com

Autónoma de Nuevo León, General Escobedo, N.L., México

2 Facultad de Agronomía, Universidad Autónoma de Nuevo León, Mexico

and

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protocol, among other factors.

**6. Conclusions**

fertilization).

**References**

2012;**15**(1):15-27

DOI: 10.2527/af.2015-0009

**Author details**

Fernando Sánchez Dávila1

Nuevo León, UA Marín, Mexico

Hugo Bernal Barragán<sup>3</sup>

**Photo 2.** Observation and manipulation of the uterine horns to carry out the technique of artificial insemination by laparoscopy.

**Photo 3.** Observation of uterine horns in a goat through laparoscopy with 12 hours of water diet.

(IVM), or the Robertson Pipette from Minitube. The objective is to inseminate in the middle part of both uterine horns, depositing half of the dose in each one of them. The technician must take between 2 and 3 min to inseminate the goat. When fresh semen is used, pregnancy percentages are reached above 80. With frozen semen, percentages are reached between 50 and 80% pregnancy.

Once the artificial insemination is performed, the endoscope is removed, and a commercial disinfectant is placed in the incisions that were made. The amount of sperm deposited per dose varies from 40 to 100 million. The results of this AI technique will depend on other factors, including goats' body condition, insemination time, race, year time, and synchronization protocol, among other factors.
