Reprod PhysEndocrin ANS 3319
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This 11 page Class Notes was uploaded by Laury Kreiger on Friday September 18, 2015. The Class Notes belongs to ANS 3319 at University of Florida taught by Joel Yelich in Fall. Since its upload, it has received 169 views. For similar materials see /class/206669/ans-3319-university-of-florida in Animal Science at University of Florida.
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Date Created: 09/18/15
ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 Regroductive Cyclicity Follicular Phase 1 Review of estrous cycle 2 Significant events during follicle phase Fig 84 0 9 progesterone end of luteal phase 0 Removal of feedback on preovulatory surge center 9 GnRH results in FSHILH FSHILH release controlled by estradiol 9 Tonic GnRH center ventromedial nucleus amp arcuate nucleus influenced by progesterone Responsible for basal LH during entire estrous cycle Stimulates follicle development results in slight in estrogen Small amplitude high frequency LH pulses 9 Surge Center preoptic nucleus amp suparchiasmatic nucleus Threshold level of estrogen absence of progesterone from ovulatory follicle o feedback of estrogen 0 Surge ofGnRH surge LH amp ovulation 91 m ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 0 Summary of endocrine events leading to ovulation ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 3 Folliculogenesis 0 Wavelike patterns of follicle development 2 4 wavescycle Fig 87 0 Occurs during estrous amp menstrual cycles 9 Several nonovulatory waves during estrous cycle 93 ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 O O O o Nonovulatory follicles fail to ovulate clue to progesterone 9 Single ovulatory wave after luteolysis amp loss of progesterone Waves also occur during prepubertal period pregnancy anestrus amenorrhea 0 Do not yield ovulatory follicles no estrogen threshold reached to ovulation Folliculogenesis involves recruitment selection dominance atresia Recruitment 0 Small antral follicles grow amp develop as they enter gonadotropin sensitive pool a High FSH low FSH no inhibin low estradiol Some follicles undergo atresia Selection Growing follicles that have not undergone atresia Low FSH moderate LH low inhibin 0 Selected follicles either become dominant or undergo atresia o Polytoccous several follicles selected pigs dog cat sheep 0 Monotoccous typically a single follicle selected cattle horse humans Dominance One or more large preovulatory follicles continue to develop 0 Major effect on other antral amp recruited follicles 0 Low FSH high LH high inhibin high estrogen o Inhibin from antral follicles selectively inhibits FSH 0 Estrogen blood flow to nonselected follicles m Follicle degeneration which occurs continuously throughout folliculogenesis 90 of all follicles undergo atresia o Occurs during initial part of each wave even wave where follicles ovulate ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 Endocrine patterns during preovulatory follicle development Fig 88 FSH a Medium FSH o No inhibin o Medium inhibin o 0 Low LH LH 0 Low estrogen estrogen Low FSH inhibin wt LH estrogen Progesterone regulates LH Pulses Luteinizing Hormone LH VI U1 3 3 1 L W U L rogesterone 394quot p D Z 4 6 8 10 12 14 16 Day of the Estrous Cycle 18 20 D D Progesterone regulates LH secretory pattern hence follicle development LH pulses LH pulses LH Surgt ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 o Endocrine patterns during follicle development Fig 88 centered around progesterone Low to progesterome early clays 08 amp late cycle clays 1820 0 LH pulse frequency follicle development 0 Elevated amp sustained progesterone mid cycle clays 817 9 w LH pulse frequency pulse amplitude 0 Follicle turnover no ovulation 0 Low progesterone late cycle clays 1820 9 LH pulse frequency follicle development 4 Estrogen secretion and function 0 The 2 cell 2 gonadotropin model of estrogen production 0 LH stimulates thecal cells LH receptors 9 Cholesterol converted to testosterone 0 Testosterone diffuses out of cell enters granulosa cells 0 FSH granulosa cells FSH receptors 9 Testosterone converted to estrogen I I g LH on 39 cells 0 Prepares prevoulatory follicle for LH surge 9 Function of estrogen Primary target is reproductive tract 0 blood flowhyperemia Facilitates secretory activity of tract Delivery of leukocytes to submucosal region results in leukocytosis o Genital swelling edema in vulva 9 Increased mucosal secretions Cervixvagina lubrication flush foreign material from tract post copulation Cow provides pathway for sperm to traverse cervix to uterus o Initiation of uterine gland growth ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 0 Elevated myometrial tone Assist in sperm transport Targets brain 0 Increased lordosis under low progesterone 9 Increased phonation physical activity ANS 3319C Reproductive Physiology and Endocrinology Spring 2009 o Estrogens in humans Menopause normal ovarian function ceases to exist 0 Dramatic decline in follicularoocytes over women s lifetime Fig 812 Estrogen deficiency results in O O O Genital atrophy D 39 quot by r 39 quot tract Modification of lipid metabolism amp vascular walls Increase in physiological loss of bone osteoporosis Vasomotor symptoms Hot Flashes ANS 3319C Reproductive Physiology and Endocrinology Estrous Synchronization amp Heat Detection in Cattle Objectives 1 To introduce the tools needed to implement effective estrous synchronization programs 2 To introduce the different estrous synchronization programs available to producers 3 To review the process of heat detection in beef cattle and discuss the tools that can be used to increase it efficiency Estrous Synchronization 1 Enhances the use of artificial insemination Al by increasing the number of cattle in estrus 2 3 4 5 vvvv 6 v over a shorter period of time compared with unsynchronized cattle See gure below 35 3 30 3 25 UUbyncltm39zed Q 20 ISnclmnized l g 15 x 0 10 Ill H l ri Ir Ill r H H l 1 I O 2 4 6 8101214161820 Day after PGFZDL treatment Allows producers to effectively manage breeding schedules to fit in with other required work Greatly reduces or eliminates labor and time required for heat detection Greatly reduces days needed to inseminate the cattle Groups cattle into calving groups resulting in o Calves are more uniform in weight and age at weaning 0 Concentration of labor for calving and breeding seasons 0 Shortens the duration of calving season and subsequent breeding season Cows that breed early in the breeding season tend to wean older heavier calves and more uniform calves during their lifetime and also maintain a yearling calving interval
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