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Theriogenology Exam 1

Theriogenology Exam 1. Amy Fayette October 2005. What are the 4 temporary structures that secrete hormones. Follicle CL Placenta Endometrial cups in the equine. What does the follicle secrete. Estrogen Inhibin Progesterone (in some species). What does the CL secrete. Progesterone

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Theriogenology Exam 1

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  1. TheriogenologyExam 1 Amy Fayette October 2005

  2. What are the 4 temporary structures that secrete hormones • Follicle • CL • Placenta • Endometrial cups in the equine

  3. What does the follicle secrete • Estrogen • Inhibin • Progesterone (in some species)

  4. What does the CL secrete • Progesterone • Estrogen • Oxytocin • Testosterone

  5. What does the placenta secrete • Progesterone • Estrogen • Relaxin

  6. What do the endometrial cups in the equine secrete • PMSG

  7. At what stage of gestation do the endometrial cups secrete PMSG • 36-120 days

  8. What is the function of inhibin • Inhibits other follicles

  9. What is the significance of inhibin • Prevents multiple births in monotocous species (more inhibin means lower ovulation rates)

  10. What is the function of relaxin • Prepares the genital tract for parturition

  11. What is the only constant part of the estrus cycle between various species • The CL has a consistent length

  12. How long does the CL last on average • 14-15 days

  13. Which reproductive hormones are species specific • None

  14. How do the repro hormones differ from species to species • In their sensitivity (dosage, frequency, time or stage of estrous cycle)

  15. What is the main drive of puberty in farm animals • Body weight • Needs to be 65% of the adult body weight

  16. What happens to the estrus cycle and to pregnancy when an animal is under stress • They may stop cycling • Pregnancy is often still supported

  17. What does the hypothalamus secrete • GnRH • CRH • Growth HRH • TRH • PIH (dopamine??)

  18. What are the functions of prolactin • Leuteotrophic (can be luteolytic) • Maternal behavior (pseudocyesis) • Lactation

  19. What is the effect of PIH • Decreased prolactin

  20. What is the effect of TRH • Increased TSH and prolactin

  21. How do you get the max effect from oxytocin • Have circulating estrogen • Therefore oxytocin is not as effective when given several days after parturition for retained fetal membranes

  22. What is the function of ACTH • Initiation of parturition • Suppression of lactation

  23. What is the function of STH (aka GH) • Onset of puberty • Maintenance of lactation

  24. FSH has peak release at what point in the cycle • Proestrus • estrus

  25. FSH has its highest levels in what type of animals • Castrates, ovariectomized and post menopausal animals

  26. What allows FSH levels to reach these higher levels • Lack of inhibition

  27. What is the function of FSH • Stimulates growth of antral follicles which increases the production of estrogen

  28. FSH is inhibited by • Via decreasing GnRH • Progesterone • Estrogen • Testosterone

  29. What is the function of LH • Stimulate maturation and ovulation of antral follicles • Stimulate formation and maintenance of the CL

  30. When is the peak release of LH • During estrus

  31. Peak release of LH coincides with what other hormone • FSH

  32. LH demonstrates a ________ release throughout the cycle • Pulsatile

  33. Long term use of LH type products may cause ________ • Anti-hormone antibodies (may need to increase dose)

  34. HCG has primarily ______ activity • LH

  35. PMSG has primarily ____ activity • FSH

  36. Where is HCG derived from • Human chorion (30-60 days of gestation)

  37. Other than HCG what else can be used for LH activity • GnRH (stimulates LH)

  38. What are the benefits of using GnRH over HCG • Smaller molecule so less antihormone stimulation • More physiological

  39. What are the applications of LH usage in therio • Insure ovulation • Tx of cystic ovarian dz • Increase size of CL • Encourage descent of the testicles

  40. If using LH to insure ovulation what are the important things to remember • Response w/in 36 hours • Requires a mature follicle to respond

  41. What species is LH used as a treatment of cystic ovarian disease • Dairy cattle

  42. Why would you want to use LH to increase the size of the CL • Increase progesterone which some people believe might increase conception and decrease early embryonic losses

  43. How does using LH cause descent of the testicles • Will increase testosterone

  44. What can be used for FSH activity • HMG (human menopausal gonadotropin) • PMSG

  45. When can PMSG be extracted • 40-120 days of gestation

  46. What cases will give higher levels of PMSG • Pony mares and twin pregnancies will give 2 times the PMSG

  47. What case will give less PMSG • Mule (1/8x)

  48. What is the benefit with using HMG vs PMSG • HMG has primarily FSH activity whereas PMSG has variable amounts of FSH and LH activity

  49. What are the uses of FSH in therio • Superovulation • Promote estrus • Initiate cyclic activity “out of season” • Induce earlier return to estrus after lactation • Earlier onset of puberty

  50. What is a problem with using FSH to promote estrus • Breeding results are often depressed

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