1 / 45

Animal Science 434 Reproductive Physiology

Animal Science 434 Reproductive Physiology. Puberty. Development of Hypothalamus and GnRH Release Centers. Males and Females are Different!!!. Hypothalamus GnRH Control Centers in the Female. Why does the male only have tonic control centers develop?. Male Brain Development. T. Testis.

ditch
Download Presentation

Animal Science 434 Reproductive Physiology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Animal Science 434Reproductive Physiology Puberty

  2. Development of Hypothalamus and GnRH Release Centers Males and Females are Different!!!

  3. Hypothalamus GnRH Control Centers in the Female Why does the male only have tonic control centers develop?

  4. Male Brain Development T Testis T E2 Surge Center Does not Develop Blood Brain Barrier

  5. Female Brain Development Placenta E2 E2 E2 E2 Ovary Blood Brain Barrier

  6. Female Brain Development aFP + E2 Placenta E2 E2 E2 E2 Ovary Surge Center Develops Blood Brain Barrier

  7. Fundamental Male and Female Differences PulsePatterns Surge + Tonic Tonic

  8. Puberty • The ability to accomplish reproduction. • Definitions in Male and Female • See Textbook • Age of Puberty • See Textbook

  9. Puberty Genetic Hormonal Environment Nutritional

  10. Role of GnRH Pulses Hormonal

  11. GnRH Pulses Determine Puberty • Prepubertal period • minimal GnRH release • FSH and LH low • minimal to no folliculargenesis or spermatogenesis • Puberty • increase in the pulse frequency and amplitude of GnRH release • increase in FSH and LH pulses • folliculargenesis and spermatogenesis occur

  12. Hormonal Changes in the Female

  13. Hypothalamic Secretion of GnRH Low Amplitude and Frequency Senger, 2012

  14. Hypothalamic Secretion of GnRH Senger, 2012

  15. Hypothalamic Secretion of GnRH Pattern!! Senger, 2012

  16. Surge Tonic

  17. Potential Regulators of GnRH Pulses at Puberty • Development of surge center • Change in the feedback sensitivity to estradiol

  18. Development of the Hypothalamic GnRH Surge Center Puberty = 28 - 30 weeks

  19. Development of the Hypothalamic GnRH Surge Center Puberty = 28 - 30 weeks Positive Feedback is possible prior to puberty

  20. Negative Feedback Decreased Neg. Feedback Changes in Feedback Sensitivity to Estradiol

  21. Puberty in the Female

  22. Silent Ovulation at Puberty

  23. Steroid Hormone Influence on GnRH Neurons Estrogen and Progesterone receptors for negative feedback. Kisspeptin neurons - - GnRH neuron - - + GnRH GnRH neuron + + Kisspeptin neurons Estrogen receptor for positive feedback.

  24. Hormonal Changes in the Male

  25. Genetics

  26. Influence of Breed on Age of Puberty Average Age at Puberty (Months)

  27. Nutrition

  28. Availability of Energy Changes with Growth

  29. Effect of 2-deoxyglucose on LH Pulses GnRH Before 2DG During 2DG 3 2 LH (ng/ml) 1 0 1 2 3 4 5 6 7 8 9 10 11 Time (hours)

  30. Effect of 2-deoxyglucose on LH Pulses GnRH Before 2DG During 2DG 3 2 LH (ng/ml) 1 0 1 2 3 4 5 6 7 8 9 10 11 Time (hours) Decreased Amplitude and Frequency

  31. Metabolic Signals Influence GnRH Neurons Pre-pubertal or Starvation - Glucose sensingneurons Blood Glucose - Kisspeptin neurons - ? - Neuropeptide Y neurons - - GnRH neurons - - - GnRH - Leptin - - ? Fatty Acid sensing neurons - Kisspeptin neurons - Adipocytes (Fat) Blood Fatty Acids

  32. Metabolic Signals Influence GnRH Neurons + Post-pubertal Glucose sensingneurons Blood Glucose + Kisspeptin neurons + ? + Neuropeptide Y neurons + + GnRH neurons + + + GnRH + Leptin + + ? Fatty Acid sensing neurons + Kisspeptin neurons + Adipocytes (Fat) Blood Fatty Acids

  33. Effect of Nutrition on Puberty 12 1.5 lb/day 2.0 lb/day 10 8 1.2 lb/day Body Weight (X 100 lbs.) 6 Puberty 4 2 0 4 8 12 0 16 20 24 Age (months)

  34. % Mature Weight at Puberty Dairy Cattle 30-40% Beef cattle 55-65% Sheep 40- 63%

  35. Environmental and Social Conditions

  36. Effect of the Number of Females Housed TogetherandExposure to A Male

  37. 32 Weeks 28 Weeks 24 Weeks 24 Weeks

  38. Influence of Growth Rate and Bull Exposure on Age of Puberty Moderate Growth Rate High Growth Rate 500 449 428 422 400 375 300 Age at Puberty (days) 200 100 0 Heifers only Bull Exposure

  39. Mechanism of Social Effects • Pheromones • Impacts on GnRH • Nasal receptors impact nerve tracts to the hypothalamus

  40. Puberty Genetic Hormonal Environment Nutritional

  41. Recommended Age to Breed • Heifer 15 months (65% mature BW) • Bull 15 natural mating, 12 months AI, 9 - 10 months IVF • Filly 2-3 years • Colt 2 years (immature behavior until 3) • Gilt 8 – 9 months • Boar 9 months

More Related