**Figure 1.**

*Animal Reproduction in Veterinary Medicine*

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

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

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

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

them affects the final result cross-sectionally, which is pregnancy.

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

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

**2. Reproduction in goats**

less females.

goat used.

national livestock shows.

**76**

*Factors that affect the reproductive response in goats.*

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 low fertility and therefore gestation.
