1. Animal Science 434 Reproductive Cycles in the Female

2. Terminology Estrus is a noun. –The cow is displaying estrus. Estrous is an adjective. –The length of the estrous cycle is 21 days. Oestrus and Oestrous –British and European spellings Estrus and Heat are synonymous

3. Terminology (cont.) Anestrus –When the female is not having repeated estrous cycles.

4. Types of Cyclicity Polyestrus

5. Types of Cyclicity Seasonally Polyestrus Short day breeders (Fall) Long day breeders (Spring)

6. Type of Cyclicity Monoestrus DogWolfBear

7. Average Reproductive Cycles Species Length of Length ofOvulation Length of Estrous Cycle EstrusPregnancy cow 21 days 18 hr11 hr after282 days polyestrusend estrus ewe 17 days 29 hrnear end148 days seasonal (fall)estrus sow 21 days48-72 hr35-45 hr115 days polyestrusafter start estrus mare 21 days4-8 days3-6 day of335 days seasonal (spring)estrus polyestrus(1-2 days before end of estrus)

8. Variation in Cycle Types ExampleType of Follicular Ovulation & CL CycleDevelopmentCL Formation Function Cow, ewe, LongSpontaneousSpontaneousSpontaneous sow, mare rats, mice, ShortSpontaneousSpontaneous Induced hamsters (4 days) (prolactin) rabbit, cat,InducedSpontaneous Induced Induced mink, ferret, (LH surge) otter, alpaca

9. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 LH FSH PGF 2  Estradiol Progesterone MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation

10. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 LH FSH PGF 2  Estradiol Progesterone MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation

11. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 LH FSH PGF 2  Estradiol Progesterone MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation

12. Follicular Phase Proestrus follicle enlarges estrogen increases vascularity of the female reproductive tract increases endometrial glands begin to grow estrogen levels peak

13. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 LH FSH PGF 2  Estradiol Progesterone MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation

14. Estrus allows male to mount estrogen decreases LH surge occurs ovulation 24-48 hr after surge of LH uterine motility high with contractions moving toward oviduct sperm transport is optimal cervical mucus volume increases Follicular Phase

15. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 LH FSH PGF 2  Estradiol Progesterone MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation

16. Luteal Phase Metestrus estrogen low ovulation in cow corpus hemorrhagicum present uterus  contractions subside  endometrial glands continue to grow and become coiled  in cattle bleeding occurs FSH increases  triggering growth of follicles

17. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 LH FSH PGF 2  Estradiol Progesterone MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation

18. Luteal Phase Diestrus progesterone high FSH  Increases at some point to cause growth of ovulatory follicle Uterus  secrets fluid but volume gradually decreases  contraction stop  CL regresses at the end of this period if female is not pregnant due to PGF release

19. Characteristics of Estrous Cycles Cow Ewe Sow Mare Estrous cycle (days) 21 17 21 21 Proestrus (days) 3-4 2-3 3-4 2-3 Estrus12-18 hr24-36 hr48-72 hr4-8 days Metestrus (days) 3-4 2-3 2-3 2-3 Diestrus (days)10-1410-12 11-13 10-12

20. Causes of Anestrus Pregnancy Presence of Offspring Season Stress Pathology Nutrition

21. Gestational Anestrus

22. Progesterone during pregnancy –negative feedback After parturition anestrus continues –progesterone exposure during pregnancy –hypothalamus Lacks estradiol positive feedback allows time for uterine involution

23. Seasonal Anestrus Horses are long day breeders!

24. Sheep are short day breeders!

25. Estradiol

26. Negative Feedback increases Decreased Negative Feedback

27. Estradiol

28. Seasonal Anestrus just like entering puberty silent ovulation

29. + +

30. Silent Ovulation Anestrus Estrus

31. Lactational Anestrus

32. Suckling Effect on LH

34. Lactational Anestrus Suckling Other offspring factors –visual encounter –olfactory encounter –auditory encounter Prolactin –inhibits GnRH release –major infertility problem in women who are not lactating

35. Nutritional Anestrus

36. Menstrual Cycle

37. FSH LH Estradiol Progesterone Follicle Ovulation Corpus Luteum Corpus Albicans 2468101416182022242628212 Anterior Pituitary Hormones Ovarian Hormones Ovary Uterine Endo- metrium Recruitment Selection Dominance Recruitment

38. FSH LH Estradiol Progesterone Follicle Ovulation Corpus Luteum 2468101416182022242628212 Anterior Pituitary Hormones Ovarian Hormones Ovary Uterine Endo- metrium Menses 5 days 5 days 5 days 5 days Follicular Phase 9 days Luteal Phase 14 days

39. Variation in Menstrual Cycle Length 35-day cycle Ovulation 14 days Menses Foll. PhaseLuteal Phase Menses 28-day cycle Menses Luteal Phase Menses Foll. Phase 25-day cycle Menses Foll. Phase Menses Luteal Phase 14 days 5 days 6 days 9 days 16 days 14 days Breast Tenderness Breast Tenderness

40. Menstural Cycle Length AGE  Length  15 - 19 year olds 35 days  30 year olds 30 days  35 year olds 28 days  Variation  More in teenagers  Less in women in peak reproductive years

41. Rest are extra slides not used in 2006

43. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation

44. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 LH FSH Estradiol MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation

45. CA Days Relative to the Gonadotropin Surge 012345678- 2- 3- 4- 5- 6-7 LH FSH PGF 2  Estradiol Progesterone MetestrusDiestrusProestrusDiestrusEstrus CL Ovulation