Female Reproductive System of Animals

The female not only contributes the female sex cell (ovum) but also provides the necessary environment in which the fetus is nourished. These functions are performed by the primary and secondary organs of the reproductive system. A pair of ovaries are the primary organs of reproduction and produce not only ova but also the hormones required for the normal sexual behavior of females. The secondary organs of reproduction are a pair of oviducts (Fallopian tubes), the uterus, the cervix, the vagina, and the vulva. The mammary glands are also considered accessory sex organs as they are closely related to the completion of reproduction by the nourishment of the young one.

The development of the reproductive organs starts before birth during the embryonic stage, but they remain quiescent. After birth, the reproductive organs develop gradually until the female attains a specific weight at a certain age when she becomes sexually mature, i.e. capable of producing viable gametes. The age at which a female becomes sexually mature is called puberty.

Ovary:
There is a pair of ovaries. These are source of ovum which is produced through the process of oogenesis and ovulation. These are also concerned with production of ovarian hormones as estrogen, progesterone and relaxin. Ovary is supported dorsolaterally by broad ligament and medially by proper ligament. Size, shape and location of ovary vary with species, stage of estrus and stage of gestation.

Oviduct or Fallopian Tube: The oviduct is a tortuous, tubular structure of muscular and epithelial tissues. It reaches from the ovaries to the tapered end of the uterine horn. The oviduct consists of three parts: the isthmus or narrow portion which adjoins the uterine horns; the ampulla, which is slightly wider; and the infundibulum, which opens into the peritoneal cavity.

Uterus:The uterus consists of a body and two horns. It is a muscular and irregularly tubular organ, the size of which increases during successive pregnancies.

Cervix: It is sphincter like segment of reproductive tract which anatomically and physiologically separates the uterine lumen from vagina. Externally it has thick wall and internally has constricted lumen. Function is to close uterine lumen against micro and macroscopic intruders. It remains close at all the time except during estrus and at the time of parturition. At estrus cervix serves as passage way for sperm. In pregnancy the cervical mucous hardens and seals off the canal by forming cervical plug and cervical seal which liquefy shortly before parturition. At parturition cervix dilates and allows passage to fetus and fetal membrane.

Vagina:The thin but elastic-walled tubular connection of the cervix with the vulva is called the vagina. It is a common passage for the repro­ductive and the urinary tract. The epithelial lining of the vagina undergoes changes during the estrus cycle.

Vulva:The external opening of the female genitalia is called the vulva. It includes the clitoris and the vestibule. The clitoris is a structure of erectile tissue (homologous with the male penis) located just inside the lower junction of the vulvular lips. The external opening of the reproductive tract of the cow lies just below the anus. The thick labia majora are covered with fine hair.

Vestibule:It is located between vulva and vagina and is comprised of two labia. The dorsal and ventral comissure and clitoris form the caudal termination of genital tract. Urethra opens into cranial ventral portion of vestibule. Vestibule has several circular or sphincter like muscles that close the genital canal to the outside. These muscles attach to the perinial body, the sphincter muscle of anus and caudal and last sacral vertebrae. Just during parturition the vestibule acts as the point of attachment of the entire genital tract to contract when expelling the fetus.

  Puberty in Females 

Puberty is the age when animal attains the ability to release the gametes and manifest complete sexual behavioral sequences. Puberty age is very important parameter for the successful livestock farming. Those animals which attain puberty earlier give more production.

Factors affecting Puberty in Females:

Genetic makeup of the animal - Exotic breeds attain puberty earlier as compared to local breeds. Exotic dairy breeds attain Puberty in 12 – 15 months. Exotic Beef breeds attain puberty in 15 – 18 months. Local breeds attain puberty at the age of 18 – 24 months.

Nutrition - In underfed animals, puberty is delayed. On balanced diet puberty is attained earlier. When the animal gains 55 – 60% of adult body weight, then animal attains puberty.

Temperature - In summer the temperature is very high, due to heat stress growth rate is low and puberty is delayed.

Management - When males and females are kept together then puberty comes earlier and vice versa. It is due to sight and visualization.