Anatomy and Physiology of Beef Cattle

Listed below are some quick facts of information from “Anatomy and Physiology of Beef Cattle Fact Sheet”, written by Taylor Davis.

Female External Genitalia:

Vulva

• The external part of the reproductive tract. The thickened folds of skin of the structure are sensitive to changes in estrogen, the hormone responsible for estrus (heat).
• Provides protection to minimize entry of foreign material into vagina.
• In heat, the vulva will swell and become red, due to increased blood flow, can be useful in estrous detection when coupled with other signs.

Clitoris

• Highly innervated tissue located in the ventral commissure that is very sensitive to tactile stimulation.

Vestibule

• Common duct for urine and fetus during parturition.  Functions to stimulate penis during copulation.
  

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Female Internal Reproductive Tract:

Broad Ligament

• Double layer of connective tissue that originates from peritoneum
• 3 parts:
  • Mesometrium – the mesentery of the uterus; the largest portion of the broad ligament
  • Mesosalpinx – the mesentery of the Fallopian tube
  • Mesovarium – the mesentery of the ovaries

Functions:

• Supports and suspends the ovaries
• Houses the vascular, lymphatic drainage, and nerve supplies
  

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Fornix Vagina

• Protrusion of cervix into anterior vagina in bovine

Functions:

• Site of semen deposition during natural mating
• Secretes copious amounts of mucous during estrus
  

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Vagina

• Located between the opening to the bladder and the cervix

Functions:

• Copulatory organ during natural mating in most species
• Stimulates bull penis via temperature
• Serves as a birth canal during parturition
• Highly acidic (pH 5.7) to prevent bacterial infection
  

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Cervix **landmark when palpating**

• Sphincter-like structure
• Fibrous, collagenous, thick-walled organ with a small amount of muscle
• Prominent ridges close together

Functions:

• Production of mucous during estrous
• Sealed during pregnancy with a cervical plug to protect uterus against pathogens
• Serves as a birth canal during parturition
  

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Uterus **landmark when palpating**

• Composed of body and bicornuate uterine horns
• Placed of semen deposit during Artificial Insemination

Functions:

• Sperm Transportation
• Regulation of Corpus Luteum (CL)
• Embryo Development & Placental Attachment
• Parturition and Post-Partum Involution
  

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Oviducts (Fallopian Tubes)

• Small tubes that extend from the uterus horns to ovaries; infundibulum is also part of the oviduct

Functions:

• Transports sperm and oocyte via smooth muscle contractions to the site of fertilization
• Acts to reduce sperm numbers to prevent polyspermy
• Removes oocytes from the surface of the ovary through cilia (called fimbria on infundibulum)
• Provides proper environment needed for the oocyte and the early developing embryo
  

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Ovary:

• Supported by Broad Ligament in the peritoneal cavity
• Functioning is controlled by pituitary hormones; FSH and LH
• Ovarian structures very complicated and do many functions over a lifespan

Functions:

• Produces hormones:
  • Estrogen- from ovarian follicles; brings female into each estrous cycle
  • Progesterone- from corpus luteum (tissue from ovulated follicle); prepares the uterus for pregnancy and maintaining pregnancy
• Gamete production
  • Development, maturation, and ovulation of oocytes with each estrous cycle
    

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Major parts of male tract:

• Scrotum
• Testes
• Epididymis (caput, corpus, cauda)
• Vas Deferens/ Ductus Deferens
• Ampulla
• Seminal Vesicles/ Vesicular glands (Accessory Gland)
• Prostate Gland (Accessory Gland)
• Bulbourethral glands/ Cowper’s glands (Accessory Gland)
• Urethra
• Penis
• Prepuce and Sheath

For more information on Beef Cattle Reproduction from the University of Florida, please click here.

For the PDF file, please click here.