ADSC 2010 Exam 3 Study Guide Lectures Veterinary Social Work Reproduction and the Dairy Industry Lecture 22 March 17 I Endocrine System A Hormones B Specific Endocrine Glands 1 Pituitary 2 Hypothalamus 3 Gonads 4 Thyroid 5 Adrenal Cortex 6 Pancreas 7 Uterus 8 Placenta II Pituitary A Anterior Hormones 1 Growth Hormone 2 Thyroid Stimulating Hormone 3 Adrenocorticotrophic Hormone 4 Follicle Stimulating Hormone a Male b Female 5 Luteinizing Hormone a Male b Female 6 Prolactin a Female B Posterior Hormones 1 Oxytocin III Hypothalamus A Gonadotropin Releasing Hormone B PIF and PRF C GHRH and GHIH D Corticotrophin RH IV Gonads A Gonadal Hormones 1 Testosterone Current Lecture I Two Breed Rota Terminal Cross 1 3 A 2 3 B 2 3 A 1 3 B Replacement females Herd 1 Bull breed A Herd 2 Bull breed B Older cows Cull cows Replacement females 1 A rd ed He bre ll Bu Steers Cull heifers Steers Cull heifers Market5 II Herd 3 Bull breed C 100 of progeny A Advantages Produce replacement females Heterosis in females Maximum heterosis in terminal cross calves Can utilize complementary in terminal cross calves B Disadvantages Only 67 heterosis in females and rotational calves Requires greater number of animals to implement Requires greater management input Endocrine System endocrine glands secrete hormones carried to other parts of the body target organ tissues through the blood stream A Hormones chemical substances that are carried by the blood stream to a target organ and elicit a consistent response III B Specific Endocrine Glands 1 Pituitary anterior posterior base of brain 2 Hypothalamus above pituitary 3 Gonads testes ovaries 4 Thyroid lobes on sides of larynx 5 Adrenal Cortex close to kidneys 6 Pancreas near duodenum 7 Uterus 8 Placenta Pituitary A Anterior Hormones 1 Growth Hormone GH protein RBST bovine somatrotropin stimulates growth of bone and muscle 2 Thyroid Stimulating Hormone TSH glycoprotein stimulates thyroid gland 3 Adrenocorticotrophic Hormone ACTH protein stimulates adrenal cortex to secrete corticosteroids glucorticoids involved in energy metabolism 4 Follicle Stimulating Hormone FSH glycoprotein a Male stimulates sertoli cells in testes to initiate spermatogenesis up to secondary spermatocytes b Female stimulates granulose cells in ovary to enlarge and develop the follicle on ovary acts synergistically with luteinizing hormone to stimulate estrogen production 5 Luteinizing Hormone LH glycoprotein a Male stimulates interstitial cells leydig cells of testes to produce testosterone ICSH b Female stimulates luteal cells on ovary Ovulation Formation of corpus Luteum CL Stimulates progesterone production and secretion Acts with FSH to produce estrogen 6 Prolactin PRL Protein a Female Initiation and maintenance of lactation mammary tissue Induces maternal behavior B Posterior Hormones 1 Oxytocin protein stimulates contraction of smooth muscle of uterus and oviduct and thus IV V Stimulates transport of sperm and ova Expulsion of fetus at parturition Myoepithelial cells in mammary gland to contract and release milk milk letdown Hypothalamus mainly produces releasing and inhibiting hormones A Gonadotropin Releasing Hormone GnRH FSHRH LHRH stimulates release of FSH and LH from anterior pituitary B PIF and PRF prolactin inhibiting releasing hormones C GHRH and GHIH somatostatin stimulates release inhibition of release of growth hormones D Corticotrophin RH stimulates release of ACTH from anterior Pituitary Gonads A Gonadal Hormones steroid derived from cholesterol 1 Testosterone T2 produced in leydig cells of testes interstitial cells Stimulates spermatogenesis in the seminiferous tubules Develops maintains secondary accessory sex glands Develops secondary sex characteristics Increases libido sexual desire Increase nitrogen retention protein synthesis and muscle growth Lecture 23 March 19 I Gonads Continued A 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 III IV V VI Uterus A Prostaglandin PGF2 causes regression of corpus Luteum and restarts estrous cycle Thyroid Gland A 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 temperature Adrenal Gland A Glucocorticoids stimulate gluconeogenesis protein CHO B Mineralocorticoids regulate Na Ca and H2O balance C Adrenaline epinephrine Noradrenaline norepinephrine regulate fight or flight mechanism Stress energy Pancreas A Insulin and Glucagon Regulate the passage of glucose in out of the bloodstream Diabetes lack of insulin The Estrous Cycle in Cattle VII Ovulation occurs during estrus Progesterone blocks estrus cycles in future if pregnant Dominant follicle grows mid way through estrus cycle because of FSH peak Chart Puberty mo Estrous cycle Duration of Estrus Time of ovulation length d VIII IX Cow 6 18 21 18 hr 18 48 hr Ewe 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 Testes two main functions A Sperm production occurs in seminiferous sertoli cells tubules FSH and T 2 regulate B Androgen T2 production occurs in leydig cells LH regulates 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 ideal for sperm production Too hot cold sperm killed Tunicadartos thin muscle of scrotum and Cremaster spermatic cord muscle regulates testes distance Lecture 24 March 21 I Epididymis Maturation Storage and concentration of sperm cells A Capot epididymis head fluid absorption occurs B Corpus epididymis body C Caudal epididymis tail sperm area concentrated and stored II Vas Deferens or Ductus Deferens