ADSC 2010 Lecture 23Outline of Last Lecture I. Two Breed Rota-Terminal CrossA. AdvantagesB. DisadvantagesII. Endocrine SystemA. HormonesB. Specific Endocrine Glands1. Pituitary2. Hypothalamus3. Gonads4. Thyroid5. Adrenal Cortex6. Pancreas7. Uterus8. PlacentaIII. PituitaryA. Anterior Hormones1. Growth Hormone2. Thyroid Stimulating Hormone3. Adrenocorticotrophic Hormone4. Follicle Stimulating Hormonea. Maleb. Female5. Luteinizing Hormonea. Maleb. Female6. Prolactina. FemaleB. Posterior Hormones1. OxytocinIV. HypothalamusA. Gonadotropin Releasing HormoneB. PIF and PRFC. GHRH and GHIHD. Corticotrophin RHV. GonadsA. Gonadal Hormones1. TestosteroneOutline of Current Lecture I. Gonads ContinuedA. EstrogenB. ProgesteroneC. RelaxinII. UterusA. ProstaglandinIII. Thyroid GlandA. Triodothyronine and Thyroxin IV. Adrenal GlandA. GlucocorticoidsB. MineralocorticoidsC. Adrenaline/NoradrenalineV. PancreasA. Insulin and GlucagonVI. The Estrous Cycle in CattleVII. ChartREPRODUCTION: MALE ANATOMYVIII. TestesA. Sperm productionB. Androgen productionIX. ScrotumCurrent Lecture: I. Gonads ContinuedA. Estrogen (E2): produced in follicles on the ovary and placenta- Stimulates “estrus” behavior: standing heat (receptive to mating)- Maintenance of female secondary sex characteristics- Needed for normal growth of uterus and female reproduction tract- Stimulates duct development in the mammary gland- Interacts with oxytocin and prostaglandin to increase uterine contractibility- Increases nitrogen retention (anabolic effect)B. Progesterone (P4): produced by the corpus Luteum and placenta- Maintenance of pregnancy- Promotes uterine contractions- Acts synergistically with estrogen to stimulate “estrus” behavior- Promotes alveolar growth in the mammary gland- Inhibits LH (ovulation)C. Relaxin: produced by ovary- Relaxation and dilation of cervix during parturition - Relaxation of the pubic symphasis during parturition II. UterusA. Prostaglandin (PGF2α): causes regression of corpus Luteum and restarts estrous cycleIII. Thyroid GlandA. Triodothyronine (T3) and Thyroxin (T4): needs iodine for normal function- Accelerates all aspects of carb., lipids and protein metabolism- Increase basal metabolic rate and body temperatureIV. Adrenal GlandA. Glucocorticoids: stimulate gluconeogenesis (protein CHO)B. Mineralocorticoids: regulate Na, Ca, and H2O balanceC. Adrenaline (epinephrine) /Noradrenaline (norepinephrine): regulate fight or flight mechanism - Stress energy?V. PancreasA. Insulin and Glucagon- Regulate the passage of glucose in/out of the bloodstream- Diabetes: lack of insulinVI. The Estrous Cycle in Cattle- Ovulation occurs during estrus- Progesterone: blocks estrus cycles in future if pregnant- Dominant follicle grows mid-way through estrus cycle because of FSH peakVII. ChartPuberty(mo.)Estrous cycle length (d)Duration of EstrusTime of ovulationCow 6 – 18 21 18 hr 18 – 48 hrEwe 6 – 12 17 30 hr 24 – 27 hr** Mare 20 22 7 days 24 – 48 hrs** Sow 5 – 10 21 60 hr 38 – 42 hr** **prior to end of estrus** Cow ovulates after estrus, everyone else during estrus**REPRODUCTION: MALE ANATOMY**VIII. Testes: two main functionsA. Sperm production: occurs in seminiferous (sertoli cells) tubules/ FSH and T2 regulateB. Androgen (T2) production: occurs in leydig cells / LH regulatesIX. Scrotum: houses and protects testes and regulate temperature- Maintains testicle temperature (3-7°F in bull and 9-13°F lower in ram)- 99-95° for sperm production- Tunicadartos (thin muscle of scrotum) and Cremaster (spermatic cord): muscle regulates testes
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