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Animal Reproduction. Ms. Browning Virginia Tech February 12, 2002 This presentation has not been edited by Georgia Curriculum Office. Conditions for Fertilization. Anatomy of Male & Female must be compatible Female must be in Heat Egg must be mature. What is the function of the Male?.
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Animal Reproduction Ms. Browning Virginia Tech February 12, 2002 This presentation has not been edited by Georgia Curriculum Office.
Conditions for Fertilization • Anatomy of Male & Female must be compatible • Female must be in Heat • Egg must be mature
What is the function of the Male? • produce large numbers of live sex cells/gametes (spermatozoa) • contribute 1/2 chromosomes
What are the Male Reproductive Organs? • Testicles - produce spermatozoa & male hormone Testosterone • Scrotom - sack which carries testicles • functions as a heat regulator • Monorchid - one fertile testicle • Cryptorchid - both testes remain in body cavity (sterile) • Castration - removal of testicles • lack sex drive (libido) • gain weight quicker
What are the Male Reproductive Organs? • Epididymis - tube connects to testes • storage of spermatozoa (200 billion at a time) • spermatozoa mature as they migrate through • Vas Deferens- tube connects to epididymus • if removed, can't reproduce = vasectomy
What are the Male Reproductive Organs? • Urethra - begins at bladder and continues through penis • Sigmoid Flexure- "S" shape in urethra allows for extension of penis outside of body for reproduction
Male Accessory Sex Glands • Prostate • 2 Seminal Vesicles • 2 Cowper’s glands
What is the function of the Accessory Sex Glands? • provide medium for transporting sperm • adds volume • provides nutrients • cleans & flushes urinary tract
Artificial Insemination • Required Equipment • A.I. Rod • Semen Straw • Lube • Genetic Diversity • Select the bulls you want to use based on EPDs • Compared to Natural Mating
Artificial Insemination vs.. Natural Mating Pros - MoreGenetic Diversity - Don’t Have To Maintain A Bull - More Controlled Breeding Season - More Cost Effective - More Hygienic - Easier To Determine Calving Date Cons - More Equipment Required - Heat Watch Required - Experienced A.I. Technician - More Labor Intensive - More Time Consuming
Take out a Piece of Paper • Quiz • 1. What are the main structures of the Male Reproductive Tract? • List at least 4 • 2. What are the advantages of Artificial Insemination? • List at least 3
What is the function of the female? • contribute 1/2 chromosomes • care for young in uterus and after birth until weaning
What are the Female Reproductive Organs? • Vulva - exterior portion of reproductive tract • provides visual signs of heat • Vagina - between vulva & cervix • Cows & Ewes: semen is deposited here • Mares & Sows: semen is deposited in the cervix
What are the Female Reproductive Organs? • Cervix - "Mouth of the womb" • opening into uterus • at birth cervix stretches to allow baby to pass • during pregnancy cervix becomes blocked with a mucous plug to prevent infection
What are the Female Reproductive Organs? • Uterine Horns- two branches of uterus • Fallopian Tube- uterine horn becomes a small tube • Site of fertilization • lined with cilia which aid in egg migration
Ovaries • located at end of fallopian tubes • possesses large number of eggs in all stages of development • this is all the eggs she will ever have, unlike the male • very few eggs reach maturity • if not fertilized, the egg is reabsorbed by the body
Reproduction in Males • After sexual maturity, sperm production is continuous • Testosterone is responsible for: • growth, development & activity of accessory glands • survival of spermatozoa • secondary sex characteristics:male voice, sex drive
Reproduction in Males • Semen - collective term for all fluid ejaculated • sperm and fluid from accessory glands
Reproduction in Females • Farm animals reach sexual maturity at 4 months (sow) to 24 months (mare), then • Female comes in heat (estrus) • Egg released by ovary • Egg travels down tube until fertilized by sperm • Estrogen - female hormone which regulates estrus
What does "in heat" mean? • Heat is the time when a female is receptive to the male and will allow breeding to take place • Heat is actually divided into 4 phases of the cycle.
Estrous Cycle: • Proestrus: ovary is about to release an egg • Estrus: female receptivity • Metestrus: uterus prepares for pregnancy • fertilized egg attaches to uterus • Diestrus: longest period of cycle • inactive • Estrous Cycles stop after conception, and begin soon after Parturition (birth)
Females also show external signs of "Heat" • aggressive behavior • swelling and/or color change of vulva
Beef (Bovine) Terms • A Mature Male is called a: Bull • A Mature Female is called a: Cow • The act of Giving Birth is called: Calving • A Castrated Male is called a: Steer • An Immature Female is called a: Heifer
Pig (Porcine) Terms • What do you call a mature male hog? Boar • What do you call a mature female hog? Sow • What do you call the act of giving birth? Farrowing • What do you call a castrated male hog? Barrow • What do you call an young female hog? Gilt
Poultry (Ovine) Terms • What do you call a mature male? Rooster • What do you call a mature female? Hen • What do you call a young female? Pullet • What do you call a castrated male? Capon
Horse (Equine) Terms • What do you call a mature male horse? Stallion • What do you call a mature female horse? Mare • What do you call a castrated male horse? Gelding • What do you call a young horse? Foal or Colt • What do you call an immature female horse? Filly • What do you call the act of giving birth for horses? Foaling