**2. Reproduction in goats**

In most areas of the world, goats are mated once yearly in the fall, during their natural mating season, for spring kidding [3–5]. Animals bred at this time are more likely to get pregnant and have multiple kids. A longer breeding season allows for flexibility in breeding and kidding dates to times when the climate is more favorable, and forage is available for the lactating doe. In addition, dates of ethnic/alternative markets should also be considered in the decision about when to breed females. How long the males are kept in with females for mating determines how long kidding will last, but a 40 to 45-day breeding season will guarantee that each doe has had at least two opportunities to come into heat. The male-to-female ratio in this breeding system is approximately 1 male per 30–40 females, but in synchronized breeding, this ratio should be 1 male with 20 or less females.

Likewise, under range conditions, bucks are often maintained with the doe herd throughout the year for continuous breeding. In such a system, proper health management is difficult and only limited supervision can be provided during kidding [1]. Care is also required to routinely remove offspring from the herd to avoid mother/son and father/daughter mating's. Although buck exposure is continuous, kidding under continuous mating will eventually follow seasonal breeding patterns, depending on the location of the farm and the breed of goat used.

However, globally, in intensive milk production systems, the use of basic reproductive techniques has been applied more extensively, for example the estrus synchronization techniques, artificial insemination, (AI), is being used more commonly by goat producers [6]. Artificial insemination makes it possible to obtain or transfer genetic material domestically and internationally. Many goat producers, both meat and dairy, utilize AI to produce animals that are more desired by markets and consumers as well as animals that will do well at local, state and national livestock shows.

#### **2.1 Perspectives and advances in the study of the estrous cycle of the goat**

Currently the estrous cycle is being studied from a perspective of hormonal changes according to the ovarian structures that are present during each of the phases that occur (follicular and luteal) [7, 8]. The above is with the objective of evaluating the size of structures and correlating them with hormonal profiles. Considering that by understanding the physiology and anatomy and the perspective of manipulating the oestrus cycle, we can advance or achieve higher gestation rates [9]. It has been stabilized with the application of hormonal products and/or the male effect to have an oestrus presence of 100%. However, pregnancy percentages vary greatly according to a large number of factors (see **Figure 1**), where each of them affects the final result cross-sectionally, which is pregnancy.

Estrous induction began to develop in goats and sheep for more than 50 years, where injected progesterone began to be used daily, until today with the use of two types of vaginal devices: vaginal sponge and delivery device. Controlled (CIDR), each having its advantages and disadvantages [10, 11]. The response in each of the devices has been accompanied by secondary hormones of intramuscular application that favor the development of the follicles, the synchronization of them for their ovulation and that these become corpus luteum with adequate size and with a sustainable production of progesterone. It is well known that low LH levels during the progestogen synchronization protocol will affect the fate of large follicles. However, these follicles require LH for their maintenance and development, so they

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*Reproduction in Small Ruminants (Goats) DOI: http://dx.doi.org/10.5772/intechopen.93481*

low fertility and therefore gestation.

*Factors that affect the reproductive response in goats.*

**Figure 1.**

viruses from one animal to another.

will present atresia and new ovulatory follicles appear that will grow. In long estrous synchronization protocols (above 10 days), when the vaginal devices are removed, they release little progestogen and do not completely suppress LH. With the above, an abnormal follicular development occurs, which become persistent, leading to

Changes or results in estrous synchronization programs have been modified over the years depending on the duration of insertion of the sponge or the device in the goat, however, the use of hormones to regulate goat reproduction has been maintained over the years [12, 13], with changes especially in the higher use of nonsteroidal hormones, such as those derived from prostaglandins, gonadotropin-releasing hormones, and hormones of follicular growth and development such as equine chorionic gonadotropin; being the most frequent use in the European community for health reasons. The use of steroid hormones such as progestogens continue to be used globally [14], but under the premise of using short protocols (5 to 7 days). In the present and in future years the use of short protocols of 5–7 days will be used more and more because it has a series of advantages compared to short protocols; these being the decrease in the presence of vaginitis in animals; in the case of CIDR devices, reuse them up to twice more with an effectiveness of up to 90% of estrous in goats. However, the health risk must be considered as it can contaminate bacteria,

The important thing is to be able to develop vaginal devices with a lower concen-

On the other hand, the use of estrous synchronization protocols in goats using nonsteroidal hormones in combination with the male effect has been developing more intensively in recent years. For example, the administration of double doses of PGF2α is recommended to synchronize estrous in cycling goats, with an interval of 10–14 days (appointment), which ensures that most does will present the mid luteal phase, when applying the second dose, and that all will respond with the behavior of estrus and ovulation (appointment). However, their response may vary depending on the insemination technique, the dose to be applied and the interval between

tration of progesterone and avoid being reused to avoid this type of infection.

**2.2 Will it be possible to improve the parameters of presence of estrus and** 

**pregnancy using hormones in the coming years?**
