Dairy Cattle Breeding and Selection

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Dairy Cattle Breeding and Selection

• Reproductive Anatomy
• Female Reproductive Tract

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I. Anatomy of the female system.
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Ovarian Follicle Development
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Anatomy of the Ovary
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A. Ovary

• 1. The female has two ovaries.
• 2. The ovaries are responsible for producing and
  releasing eggs.
• 3. The ovaries produce four distinct hormones
  that are involved in the reproductive process.
• 4. Each ovary is approximately 1 to 1 ½ long
  and approximately 1 in diameter.
• 5. The ovaries are located in the from the vulva
  approximately 12 18.

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• 6. They are protected by the pelvic girdle.
• 7. The entire female reproductive tract is held
  and suspended below the vertebra by the Broad
  Ligament.
• 8. Graafian Follicles form on the ovary from
  which eggs are released.
• 9. Corpus Luteum (Yellow Body) form in the
  place of the ruptured Graafian Follicle.

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Structures of an Ovary
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Fallopian Tubes/Oviduct
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B. Oviducts (Fallopian Tubes)

• 1. Divided into three distinct parts
• a. Indundibulum (Fimbria)
• 1) The funnel shaped thin tissue surrounding the
  ovary and attached to the ampulla.
• 2) It is lined with ciliated cells.
• 3) Catches the egg when released from the egg.
• 4) Sometimes fertilization does not occur
  because the egg misses the infundibulum.

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• b. Ampulla
• 1) Is the middle section of the Fallopian Tube.
• 2) Is approximately 6 8 long
• 3) Is approximately 3mm to 5mm in diameter.
• 4) Is lined with ciliated cells which aid in the
  movement of the egg.
• 5) Serves to transport the egg.

• c. Isthmus
• 1) Is the final section of the Fallopian Tube.
• 2) Is approximately 4 6 long.
• 3) Is approximately 0.5 mm to 1 mm in diameter.
• 4) The isthmus joins the ampulla at the
  ampullary-isthmic junction which is the site of
  fertilization.
• 5) Serves to transport spermatozoa and/or the
  unfertilized egg/embryo.
• 6) The isthmus joins the uterus at the
  uterotubal junction.

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Uterus
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C. Uterus

• 1. The uterus extend from the uterotubal
  junction to the cervix.
• 2. Is divided into two parts.
• a. Uterine Horns
• 1) Extend from the uterotubal junction to the
  uterine body.
• 2) Is approximately 15 long.
• 3) Contains approximately 70 120 caruncles or
  buttons in the lining.
• 4) Where the fetus grows and develops.
• b. Uterine Body
• 1) 1 ½ to 2 long in cattle.
• 2) Is located between the Uterine Horns and the
  Cervix.
• 3) This is the site of semen deposition in the
  cow when Artificial Insemination is used.

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• 3. The cow has a bicornuate uterus
  distinguished by a small uterine body and two
  distinct uterine horns.

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D. Cervix

• 1. Technically is part of the uterus.
• 2. It is a thick-walled and inelastic tube that
  joins that uterus to the vagina.
• 3. It is highly muscular with many fold to keep
  out bacteria and foreign material.
• 4. Approximately 3 in length and 1 in
  diameter.
• 5. Is the site of semen deposition in some
  species, ie. Pig, horse

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Cross section of the Cervix
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E. Vagina

• 1. Is tabular in shape, thin-walled, and quite
  elastic.
• 2. Is the organ of copulation.
• 3. Is approximately 12 16 in length.
• 4. Is the site of semen deposition in cattle and
  sheep.
• 5. Contains numerous longitudinal folds of
  tissue.
• 6. Urethral Opening is where urine empties
  into the vagina from the ureters coming from the
  bladder.
• 7. Is located between the cervix and the vulva.

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F. Vulva

• 1. Is the external portion of the reproductive
  tract.
• 2. Serves as the entrance to the reproductive
  tract.
• 3. During heat in most species the vulva will
  swell and turn red to some extent.

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G. Clitoris

• 1. Is the sexual stimulating organ of the
  female.
• 2. Homologous to the penis in the male.
• 3. Located about 1 2 inside the vagina.
• 4. Composed of limited erectile tissue somewhat
  like the tissue of the males penis.

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THE END