physiology of reproduction


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physiology of reproduction

  1. 1. Unit 1: Physiology of Reproduction <ul><li>The objective of unit 1 will be to create an understanding of reproduction from the physiological perspective. </li></ul><ul><li>Topics covered in this unit: </li></ul><ul><ul><li>Male and Female anatomy </li></ul></ul><ul><ul><li>Hormone Function </li></ul></ul><ul><ul><li>Pregnancy </li></ul></ul><ul><ul><li>Parturition </li></ul></ul><ul><ul><li>AI </li></ul></ul><ul><ul><li>Reproductive Technologies </li></ul></ul>
  2. 2. Unit 1: Physiology of Reproduction <ul><li>Unit 1 will cover Chapters 10 + 11 </li></ul><ul><li>Why is knowledge of the fundamentals of reproduction crucial? </li></ul>
  3. 3. <ul><li>Female reproductive organs and function </li></ul><ul><ul><li>Ovary </li></ul></ul><ul><ul><ul><li>Produces the ova & female sex hormones (estrogen & progesterone) </li></ul></ul></ul><ul><ul><li>Folliculogenesis </li></ul></ul><ul><ul><ul><li>Each follicle contains an ovum </li></ul></ul></ul><ul><ul><ul><li>Development starts from deep within the ovary with primordial follicles </li></ul></ul></ul><ul><ul><ul><li>As a follicle develops, it produces more estrogen, which continues its maturation </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  4. 4. <ul><li>Folliculogenesis cont. </li></ul><ul><ul><li>Each follicle goes through stages of recruitment, selection, and dominance. </li></ul></ul><ul><ul><li>As a follicle develops it can become: </li></ul></ul><ul><ul><ul><li>Primary </li></ul></ul></ul><ul><ul><ul><li>Secondary </li></ul></ul></ul><ul><ul><ul><li>Tertiary </li></ul></ul></ul><ul><ul><ul><li>Graafian </li></ul></ul></ul><ul><ul><ul><li>Degenerative (atresia) </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  5. 5. <ul><li>Folliculogenesis cont. </li></ul><ul><ul><li>Only the Graafian follicle can be ovulated </li></ul></ul><ul><ul><li>Ovulation occurs when the follicle ruptures, releasing the ovum </li></ul></ul><ul><ul><li>After ovulation, follicular cells form the Corpus Luteum </li></ul></ul><ul><li>The Corpus Luteum </li></ul><ul><ul><li>“ yellow body” or callous on the ovary </li></ul></ul><ul><ul><li>Produces progesterone (maintains pregnancy) </li></ul></ul>Unit 1: Physiology of Reproduction
  6. 6. <ul><li>The Oviduct </li></ul><ul><ul><li>Collects the ovulated ovum in the Infundibulum which guides the egg into the oviduct </li></ul></ul><ul><ul><li>The site of fertilization </li></ul></ul><ul><ul><li>A fertilized embryo migrates to the uterus within 3-5 d </li></ul></ul>Unit 1: Physiology of Reproduction
  7. 7. <ul><li>Uterus </li></ul><ul><ul><li>Embryo attaches to the uterine wall to begin development </li></ul></ul><ul><ul><li>Some attach in the uterine horn (sow), others in the uterine body (cow/mare) </li></ul></ul><ul><ul><li>Guarded by the cervix (gatekeeper) </li></ul></ul>Unit 1: Physiology of Reproduction
  8. 8. <ul><li>The Vagina </li></ul><ul><ul><li>The “passageway” to the reproductive tract </li></ul></ul><ul><ul><li>Female organ of copulation </li></ul></ul><ul><ul><li>Environment changes depending on the stage of reproductive cycle </li></ul></ul><ul><ul><li>Also include the urethra </li></ul></ul>Unit 1: Physiology of Reproduction
  9. 9. <ul><li>Male Reproductive Organs </li></ul><ul><ul><li>Testicles </li></ul></ul><ul><ul><ul><li>Suspended from the body </li></ul></ul></ul><ul><ul><ul><li>Produce testosterone </li></ul></ul></ul><ul><ul><ul><ul><li>Leydig or Interstitial cells </li></ul></ul></ul></ul><ul><ul><ul><li>Site of spermatogenesis </li></ul></ul></ul><ul><ul><ul><ul><li>Sperm begin development within the seminiferous tubules </li></ul></ul></ul></ul>Unit 1: Physiology of Reproduction
  10. 10. <ul><li>The Epididymis </li></ul><ul><ul><li>Stores sperm for maturation </li></ul></ul><ul><ul><li>Acquire the potential for fertilization </li></ul></ul><ul><ul><li>Most mature spermatozoa are nearest the Vas Deferens, while least mature are nearer the testicles </li></ul></ul><ul><ul><li>Some degenerate and are reabsorbed </li></ul></ul>Unit 1: Physiology of Reproduction
  11. 11. <ul><li>The Scrotum </li></ul><ul><ul><li>Two-lobed sac </li></ul></ul><ul><ul><li>Serves two purposes: </li></ul></ul><ul><ul><ul><li>Protection </li></ul></ul></ul><ul><ul><ul><li>Temperature regulation </li></ul></ul></ul><ul><ul><ul><ul><li>Can be 3-13 º cooler than body temp. </li></ul></ul></ul></ul><ul><ul><li>Tunica Dartos & cremaster muscles </li></ul></ul><ul><ul><ul><li>Responsible for raising and lower the scrotum </li></ul></ul></ul><ul><ul><li>Pampiniform plexus </li></ul></ul><ul><ul><ul><li>Acts as heat exchanger to cool blood as it enters the scrotum </li></ul></ul></ul><ul><ul><li>Begins functioning at puberty w/ hormone function 40-60d prior to puberty </li></ul></ul><ul><ul><li>What happens if this malfunctions? </li></ul></ul>Unit 1: Physiology of Reproduction
  12. 12. <ul><li>Vas Deferens </li></ul><ul><ul><li>Transport tube for sperm from epididymis to urethra. </li></ul></ul><ul><ul><li>Spermatozoa are stored in the ampulla of the V.D. until the time of ejaculation </li></ul></ul><ul><ul><li>Some species deposit sperm very quickly, and some slowly (8-12 min.) </li></ul></ul><ul><ul><ul><li>Bull, horse, ram </li></ul></ul></ul><ul><ul><ul><li>Boar, dog </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  13. 13. <ul><li>Urethra </li></ul><ul><ul><li>Canal extending from the bladder through the pelvis to the end of the penis </li></ul></ul><ul><ul><li>Carries both urinary waste and sperm </li></ul></ul><ul><li>The penis </li></ul><ul><ul><li>Male organ of copulation </li></ul></ul><ul><ul><li>Virtually every species is different in form and function </li></ul></ul>Unit 1: Physiology of Reproduction
  14. 14. <ul><li>Male Hormone Function </li></ul><ul><ul><li>Hormones stimulated and produced from the Anterior Pituitary of the brain </li></ul></ul><ul><ul><ul><li>Luteinizing Hormone (LH)-causes Leydig cells to produce testosterone </li></ul></ul></ul><ul><ul><ul><li>Follicle-Stimulating Hormone (FSH)-stimulates the seminiferous tubules to nourish developing spermatozoa </li></ul></ul></ul><ul><ul><li>Hormone function can be influenced by photoperiod (day length) </li></ul></ul>Unit 1: Physiology of Reproduction
  15. 15. <ul><li>Female Hormone Function </li></ul><ul><ul><li>Originate in the Hypothalamus and the Anterior Pituitary </li></ul></ul><ul><ul><ul><li>Gonadotropin Releasing Hormone </li></ul></ul></ul><ul><ul><ul><li>LH </li></ul></ul></ul><ul><ul><ul><li>FSH </li></ul></ul></ul><ul><ul><li>Some Hormones also released from the female reproductive organs </li></ul></ul><ul><ul><ul><li>Estrogen-follicle </li></ul></ul></ul><ul><ul><ul><li>Progesterone-CL </li></ul></ul></ul><ul><ul><ul><li>Prostaglandin-uterus </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  16. 16. <ul><li>All these activities make up the estrous cycle </li></ul><ul><ul><li>Estrous cycles range from 14-29d and can last anywhere from 12 hrs. to 9d </li></ul></ul><ul><li>Hormone function can be altered or stimulated with hormone therapy treatments </li></ul>Unit 1: Physiology of Reproduction
  17. 17. <ul><li>Pregnancy </li></ul><ul><ul><li>Onset of gestation following fertilization </li></ul></ul><ul><ul><li>Embryonic cell division every 20 hrs. </li></ul></ul><ul><ul><li>The period of attachment in the uterus is critical (20-30d cattle, 14-21d swine)-if no attachment-embryonic death occurs </li></ul></ul><ul><ul><li>Embryonic stage ends around 45d after period of formation of major organs </li></ul></ul><ul><ul><li>Fetal stage from 46d to birth </li></ul></ul>Unit 1: Physiology of Reproduction
  18. 18. <ul><li>Parturition </li></ul><ul><ul><li>Placenta is responsible for protecting the fetus and exchanging nutrients and waste with the mother </li></ul></ul><ul><ul><li>Birthing is initiated with the release of cortisol </li></ul></ul><ul><ul><li>Cortisol release causes progesterone to decrease and estrogen, PGF2a, and oxytocin to spike initiating uterine contractions </li></ul></ul><ul><ul><li>Relaxin also released from the CL-stimulates the pelvis </li></ul></ul>Unit 1: Physiology of Reproduction
  19. 19. <ul><li>Parturition cont. </li></ul><ul><ul><li>Abnormal birthing (dystocia) can result from several problems </li></ul></ul><ul><ul><ul><li>Size of fetus </li></ul></ul></ul><ul><ul><ul><li>Abnormal presentation </li></ul></ul></ul><ul><ul><ul><li>Size of pelvic opening </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  20. 20. <ul><li>What has Artificial Insemination done for the livestock industry? </li></ul><ul><ul><li>How does it fit? </li></ul></ul><ul><ul><li>What are the drawbacks? </li></ul></ul><ul><ul><li>Is it prominent in all of animal agriculture? </li></ul></ul>Unit 1: Physiology of Reproduction
  21. 21. <ul><li>Artificial Insemination </li></ul><ul><ul><li>First recorded in dogs in 1780, cattle & horses in the early 1900’s </li></ul></ul><ul><ul><li>Can increase the number of offspring from one male </li></ul></ul><ul><ul><ul><li>Bulls – 30-50 females/yr natural, 200-400 units/wk for AI (avg. 1 calf/1.5 units semen) </li></ul></ul></ul><ul><ul><li>Success of AI dependent on success of estrus detection, quality semen, semen handling, high fertility </li></ul></ul>Unit 1: Physiology of Reproduction
  22. 22. <ul><li>Semen Collection & Processing </li></ul><ul><ul><li>Collection of semen w/ and artificial vagina </li></ul></ul><ul><ul><li>Male mounts a female in estrus, or trained to mount an object </li></ul></ul><ul><ul><li>May also collect semen manually (boar, dog), or by electroejaculation </li></ul></ul><ul><ul><li>Collection timing </li></ul></ul><ul><ul><ul><li>Bulls – 2x/d, 2d/wk </li></ul></ul></ul><ul><ul><ul><li>Boars – every other day </li></ul></ul></ul><ul><ul><ul><li>Shortening or extending the schedule may decrease number of sperm/ejaculate </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  23. 23. <ul><ul><li>Evaluated for: </li></ul></ul><ul><ul><ul><li>Volume, sperm concentration, motility, abnormalities </li></ul></ul></ul><ul><ul><li>Mixed w/ an extender to dilute for more volume (milk, egg yolk, buffer) </li></ul></ul><ul><ul><li>1 unit of cattle semen should contain 10m normal, motile spermatozoa </li></ul></ul><ul><ul><li>Can be stored and used fresh for only 24-48 hrs. </li></ul></ul>Unit 1: Physiology of Reproduction
  24. 24. <ul><ul><li>Freezing semen </li></ul></ul><ul><ul><ul><li>What is it frozen in? </li></ul></ul></ul><ul><ul><ul><li>Bull semen – can be frozen and stored for indefinite time without loss of fertility </li></ul></ul></ul><ul><ul><ul><li>Boars, stallions, rams – only modest success w/ frozen semen </li></ul></ul></ul><ul><li>Inseminating the Female </li></ul><ul><ul><li>Conception rates depend on: </li></ul></ul><ul><ul><ul><li>Estrus detection, properly managed semen, timing of insemination, insemination techniques, avoiding stress </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  25. 25. <ul><ul><li>Estrus Detection </li></ul></ul><ul><ul><ul><li>Signals time of ovulation, timing of insemination </li></ul></ul></ul><ul><ul><ul><li>What is the best indicator? </li></ul></ul></ul><ul><ul><ul><li>What are some other indicators of estrus? </li></ul></ul></ul><ul><ul><ul><li>What are some technologies that might be used to detect estrus? </li></ul></ul></ul><ul><ul><ul><li>What strategies might we use to detect estrus? </li></ul></ul></ul><ul><ul><li>Timing of Insemination </li></ul></ul><ul><ul><ul><li>Duration of estrus and timing of insemination varies w/ species </li></ul></ul></ul><ul><ul><ul><li>Exhibition of estrus doesn’t necessarily include ovulation </li></ul></ul></ul><ul><ul><ul><ul><li>Sows at 3-5d after farrowing </li></ul></ul></ul></ul>Unit 1: Physiology of Reproduction
  26. 26. <ul><ul><ul><li>Insemination should occur as close to ovulation as possible </li></ul></ul></ul><ul><ul><ul><ul><li>What is the rule of thumb in cows/sows? </li></ul></ul></ul></ul><ul><li>How common is AI? </li></ul><ul><ul><li>What industries use it the most? </li></ul></ul><ul><ul><li>Which ones use it the least? </li></ul></ul><ul><li>Estrous Synchronization </li></ul><ul><ul><li>Controlling the estrous cycle and the female expression of estrus </li></ul></ul>Unit 1: Physiology of Reproduction
  27. 27. <ul><ul><li>Why use estrous synchronization? </li></ul></ul><ul><ul><li>Where is it the most appropriate and cost effective? </li></ul></ul><ul><ul><li>Prostaglandins </li></ul></ul><ul><ul><ul><li>Causes regression of a CL </li></ul></ul></ul><ul><ul><ul><li>Cows will be in estrus ~3d after injection </li></ul></ul></ul><ul><ul><ul><li>Only effective in the presence of a functional CL </li></ul></ul></ul><ul><ul><ul><li>Heifers/cows must be in d 5 – 18 of estrous cycle </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  28. 28. <ul><ul><ul><li>One-injection system </li></ul></ul></ul><ul><ul><ul><ul><li>Observe heats for first 5d of breeding season and AI all that exhibit heat </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Inject those not exhibiting heat on day 6 </li></ul></ul></ul></ul><ul><ul><ul><ul><li>All animals bred by day 11 </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Can increase P.R. from 30-40% to 50-60% </li></ul></ul></ul></ul><ul><ul><ul><li>Two-injection system </li></ul></ul></ul><ul><ul><ul><ul><li>Inject all cows at day 1 and day 14 </li></ul></ul></ul></ul><ul><ul><ul><ul><li>All cows should exhibit estrus by day 19, or breed 76-80 hrs. after second shot </li></ul></ul></ul></ul><ul><ul><ul><li>Can be a good tool in well-managed herds </li></ul></ul></ul><ul><ul><ul><li>What is a major risk w/ using Prostaglandin? </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  29. 29. <ul><ul><li>MGA & Prostaglandin </li></ul></ul><ul><ul><ul><li>MGA – feed additive that suppresses estrus in heifers </li></ul></ul></ul><ul><ul><ul><li>Feed MGA for 14d, give Prostaglandin 19d after last MGA feeding </li></ul></ul></ul><ul><ul><ul><ul><li>Most heifers should show estrus in 48-72 hrs </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Conception rate may be >80% </li></ul></ul></ul></ul><ul><ul><li>Select-Synch </li></ul></ul><ul><ul><ul><li>Injection of GnRH 7d following Prostaglandin </li></ul></ul></ul><ul><ul><ul><ul><li>Heat detect 24-36 hrs to 5d after injection </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Should have ~70% exhibit estrus </li></ul></ul></ul></ul>Unit 1: Physiology of Reproduction
  30. 30. <ul><ul><li>Co-Synch </li></ul></ul><ul><ul><ul><li>GnRH on day 0, Prostaglandin on day 7, second GnRH on day 9 and breed </li></ul></ul></ul><ul><ul><ul><li>Initiates ovulation </li></ul></ul></ul><ul><ul><ul><li>May not exhibit estrus </li></ul></ul></ul><ul><ul><li>CIDR-B </li></ul></ul><ul><ul><ul><li>Use of intravaginal progesterone implant for 7d </li></ul></ul></ul><ul><ul><ul><li>Inject prostaglandin on day 6 </li></ul></ul></ul><ul><ul><ul><li>Breed upon estrus detection from days 3-6 after injection </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  31. 31. <ul><ul><li>PG 600 </li></ul></ul><ul><ul><ul><li>Pregnant mare serum gonadotropin </li></ul></ul></ul><ul><ul><ul><li>Enhances fertility efficiency in swine </li></ul></ul></ul><ul><ul><ul><li>Helps lower days returning to estrus after farrowing, schedule breeding </li></ul></ul></ul><ul><ul><li>Natural estrus synchronization </li></ul></ul><ul><ul><ul><li>Most females will suppress estrous while nursing young </li></ul></ul></ul><ul><ul><ul><li>Removal of calf/piglet will help bring the cow into heat </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  32. 32. <ul><li>Embryo Transfer </li></ul><ul><ul><li>What is ET? </li></ul></ul><ul><ul><li>Why use ET? </li></ul></ul><ul><ul><li>Can be costly - ~$1000/hd </li></ul></ul><ul><ul><li>Superovulation </li></ul></ul><ul><ul><ul><li>Increase the number of ovulated ova </li></ul></ul></ul><ul><ul><ul><li>May increase the number of harvested embryos </li></ul></ul></ul><ul><ul><li>How is ET performed? </li></ul></ul><ul><ul><li>What components are essential? </li></ul></ul>Unit 1: Physiology of Reproduction
  33. 33. <ul><ul><li>Sexed Semen </li></ul></ul><ul><ul><ul><li>What are the advantages/disadvantages? </li></ul></ul></ul><ul><ul><ul><li>Reliability of 85-90% </li></ul></ul></ul>Unit 1: Physiology of Reproduction
  34. 34. <ul><li>Unit 1 Assignment </li></ul><ul><ul><li>Chapter Review questions pgs & 209 </li></ul></ul><ul><ul><ul><li>Pg. – 1, 2, 4, 7, 8, 9, 14, 16, 17, 18 </li></ul></ul></ul><ul><ul><ul><li>Pg. 209 – 2, 3, 5, 8, 9, 12 </li></ul></ul></ul><ul><ul><ul><li>Each question will be worth 2 points </li></ul></ul></ul><ul><ul><li>Bonus Question- What is the process of follicle development called? (2 pts.) </li></ul></ul><ul><ul><li>Due at the beginning of the next class period </li></ul></ul><ul><ul><li>E-mailed homework is encouraged—please include the course name/number in the subject line. </li></ul></ul>Unit 1: Physiology of Reproduction