Female Estrus Cycle - Ross University PDF

Female estrous cycle L. Segabinazzi DIESTRUS 2024  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Period from the beginning of one estrus to the beginning of...

Female estrous cycle L. Segabinazzi DIESTRUS 2024  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Period from the beginning of one estrus to the beginning of the next (or from one ovulation to the next) Follicular phase - estrus (Proliferative phase in women) - estrogen Luteal phase - diestrus (Secretory phase in women) - progesterone Quiescent phase – anestrus – no hormones seasonal animals like justmines and eats sheep Estrus is defined behaviorally  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Endocrine regulation of estrous cycle Hypothalamus-pituitary-ovarian axis Regulated by: Hypothalamus: GnRH Hypophysis: FSH and LH Ovary: Follicle produce Estradiol (E2), Progesterone (P4) and Inhibin Uterus: before after ovulate before Prostaglandin F2α (PGF2α)  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Hypothalamus Tonic Surge Tonic GnRH Center always active Frequency of GnRH pulses controlled by a pulse generator Affected by internal and external signals Surge Center when just happen Responsible for bursts of GnRH required to achieve preovulatory LH surge Paraventricular nucleus Oxytocin synthesis – released by posterior pituitary Axons of hypothalamic neurons extend to blood vessels of portal system GnRH affects anterior pituitary directly Endocrine response vs. Neuroendocrine response  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Pituitary gland / Hypophysis Anterior pituitary or Adeno hypophysis Continuously produces FSH Tonic Affected by inhibin (negative feedback) Preovulatory LH surge induced by the burst of GnRH from the Hypothalamic Surge center I Affected by Estradiol (positive feedback on the hypothalamic surge center) Posterior pituitary or Neuro hypophysis Responsible for storage and release of the oxytocin produced by the hypothalamus  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Ovary Medulla Vasculature, nerves, connective tissue Cortex Oocytes, Follicles, CL  Folliculogenesis P h y s i o l o g y I IMM - Reproduction Gonadotropin dependent “Resting pool” FSH Pool of inactive primordial LH follicles Dormant phase (Prophase I) No deft d FSHandladytel Committed follicle (four 8516 possibilities) yomdolotg honyon.to dependent Remains quiescent Die turn depend Begging development and atresia later Develop and ovulate Follicle activation is irreversible Finite nest Unknown what triggers the primordial follicle activation Intraovarian signaling – oocyte or granulosa cells Gonadotropin-independent growth Follicular development up to the formation of the antrum is independent of FSH or LH  Female estrous cycle P h y s i o l o g y I IMM - Reproduction has dovint fillide fill a Follicular dynamics Major a decent have Micer want do not Follicular growth occurs in waves or cohorts all Number varies between and within species Recruitment Selection Dominance Atresia  did attan IS it g of alibi Female estrous cycle P h y s i o l o g y I IMM - Reproduction Pineal gland: Melatonin Hypothalamus: GnRH Invitin breakthe cL that Pituitary Gland: FSH, LH K the fellish Ovary: Follicles - Estradiol, Inhibin, DIESTRUS Testosterone; wad Corpus luteum - Progesterone, Secondry wove Puing Relaxin, Oxytocin C L C L C L Uterus: Prostaglandin F2 alpha CL Eeyore goes to atresia xy of estradiol CL levels of Ovulation extene me toohigh Progeste check Scarramuzzi et al., 2011, Reprod. Fertil. Devel  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Follicles Primordial follicle Oocyte surrounded by a single layer of squamous cells Primary follicle Oocyte surrounded by single layer of cuboidal cells Secondary follicle Oocyte surrounded by two or more layers Zona pellucida Antral follicle – completed Meiosis I Tenting fullide Fluid accumulates within a cavity formed by follicular cells  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Antral Follicle Gonadotropin-dependent Theca externa Connective tissue Theca interna activated by Produce androgens under LH stimulation Them cells in making to who Granulosa cells Produce Estrogen, Inhibin and follicular creates fluid Responsive to FSH  Follicular deviation P h y s i o l o g y I IMM - Reproduction the program from β IGF system to keep activates the Don't low level of FSH Inhibin with developing activin A Downregulation of FSH secretion Domint produce Inhibin developing because it has estradiol Dominant follicle keepsand Subordinate follicles regress enough/more receptors for FSH Induces synthesis of LH Produces estradiol Induces ovulation  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Other ovarian structures Corpus hemorrhagicum (CH) Diester Structure left immediately after ovulation Antrum collapses and is filled with blood Corpus luteum (CL) principalz Theca interna and granulosa cells proliferate to fill the cavity, differentiate into luteal cells and produce Progesterone Large luteal cells (from granulosa; also secrete Oxytocin and Relaxin) Small luteal cells (from theca interna) Corpus albicans Remnant of old corpus luteum  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Hypothalamo-Pituitary-Gonadal Axis Diestrus Progesterone (Lack of E2) – negative feedback for LH FSH doesn’t need positive feedback. Therefore, follicles keep developing Estrus Inhibin – negative feedback for FSH Induce follicular regression Estradiol – positive feedback for LH (Surge center) Induce ovulation Female estrous cycle P h y s i o l o g y I IMM - Reproduction Pregnant Vs. Non-pregnant  Female estrous cycle - Non-pregnant P h y s i o l o g y I IMM - Reproduction Production of Ovulation progesterone by the CL Anterior pituitary produces FSH Follicular development DIESTRUS Produces estradiol Estradiol “Open” Around Day 14- CL secretes receptors of Oxytocin in 17 after ovulation oxytocin the endometrium Not pungent IF Non-maternal Endometrium PGF2α causes recognition of produces PGF2α by New estrus luteolysis of the pregnancy the stimulation of phase CL oxytocin  Luteolysis P h y s i o l o g y I IMM - Reproduction Difference between species Mares Cows CL doesn’t produce oxytocin in equine ah to this species. It is released by the posterior pituitary Uterine Horn is responsible Oxytocin from Prostaglandin synthesis by uterine Prostaglandin synthesis CL stimulates endometrium is released into the Systemic by uterine endometrium production3 of circulation. Therefore, prostaglandin ill is released into the uterine PGF2after ovaries. MEAN produced anywhere in the uterus can affect bot uterine vein. Corpus Luteum day 15 in cow Oviduct PGF2 delivered to ovary to regress CL Ovary Uterine Vein Ovarian Pedicle Through counter- PGF current exchange PGF2 moves PGF2 is picked up by into artery ovarian artery and PGF into Artery delivered back to the Uterine Artery ovary where it causes lysis of the CL  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Pineal gland Seasonality Mediated by photoperiod Perceived by eye (retina) Melatonin produced by pineal Neurohypophysis gland during hours of Adenohypophysis darkness A concutation melatonin of Synthesized from tryptophan Melatonin Increases GnRH I release in short-day breeders Small ruminants Decreases GnRH feedbath release in long-day House and cats breeders Horses and cats  sup fad Female estrous cycle P h y s i o l o g y I IMM - Reproduction Ovulation mechanisms Spontaneous ovulation – cows, horse, dogs LH peak and ovulation occurs after the peak of Estradiol Induced ovulation – cats, camelids, Interestus ovulataros External stimulus is needed for the release of LH and ovulation Interesturs  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Estrous Cycle by Species  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Cow ESTRUS Estrogens METESTRUS Estrous cycle 18 – 24 d (21) PROESTRUS Days Progesterone - Days Monovulatory Ovulation Behaviour of estros phases DIESTRUS Luteolysis Days Proestrus – Follicular growth, cow allows other cows to mount but not the bull Estrus – heat behavior, copulation Metestrus – ovulation Diestrus – Progesterone phase Ovulation 10 – 15 h after end of estrus 24 – 30 h after onset of estrus No ceased Polyestuus  of Female estrous cycle Small Ruminants Ewe Doe 0 Days Estrous cycle 13 – 19 (17) days Estrous cycle 18 – 24 d cycle (21) Seasonal, polyestrous, short-day breeders (Fall) Spontaneous ovulators Monovulatory species * (selected for multiple ovulations) Puberty associated with body development (60-70% of adult weight) – 6-12 months Duration of estrus – 30-40 h. Luteolysis is similar to cows. Ovulation occurs 24-30 h after the onset of Ovulation occurs typically towards the end estrus of estrus placenta produce program plnentadontpu.depoystem  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Sow Cycle length 21 (17 – 25) d No obvious follicular wave pattern Polyovulatory Polyestrous, nonseasonal Less breeding in warm weather Luteolysis on day ~14 CL responsive to PGF after Day 12 Estrus 2-4d Ovulation in the last 24 h of estrus Female estrous cycle P h y s i o l o g y I IMM - Reproduction Mare/jennies Cycle 15 – 26 (21) days Monovulatory* unttiple estes Polyestrus Seasonally polyestrous DIESTRUS Long-day breeders Spring transition Estrus 5-7 d Longer in early season; short in peak season Difference in LH secretion/potency than other species Ovulation in the last 48 hours of estrus Estrus = low Progesterone (rather than Estrogen) Diestrus ovulation (high Progesterone) Puberty: 8-15 months (season*) diestrus and estus Just the  Female estrous cycle C aMM melids Nonseasonal*just (in the USA), polyestrous Seasonal (summer) in the nature habitat South Auricer More associated with social behavior than day-light male Induced-ovulators Is a protein found in Triggered by an ovulation-inducing factor (Nerve Growth Factor Beta) in seminal plasma – can be induced by exogenous GnRH analogs and hCG Subcutaneous injection of seminal plasma can induce ovulation Stimulates GnRH release and maybe has local effect on follicle Dam = female camelid Mating provides some stimulus to bring about the release of LH Cervix and cranial vagina are considerably bruised in the process Female are almost always receptive Overlapping follicular waves Every 12 – 14 d If not, females spit and do not “kush” for matting Puberty (variable) 10 months to 2 Years 50% of the adult weight Female estrous cycle P h y s i o l o g y I IMM - Reproduction  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Bitch Non-seasonal monoestrus will come in autnestus thy About 6 months cycle Polyovulatory again g at Proestrus – Follicular growth, no heat behavior yet, bleeding Estrus – heat behavior, copulation Diestrus – Progesterone phase (60 d) Sam pregant or not Anestrus – Acyclic phase pregt Dogs ovulate immature oocytes (beginning of the first meiotic division - can’t be fertilized). Oocytes mature in the oviduct (2 to 5 days post ovulation – ootid, oocyte after second meiotic division) Luteolysis pattern is unknown since the length of diestrus is similar in pregnant or non-pregnant bitches  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Bitch Puberty: 6-12 months Breed dependent* Estrous cycle monitoring Behavior Vaginal cytology Progesterone LH  Female estrous cycle P h y s i o l o g y I IMM - Reproduction Queen Seasonally polyestrous Long-day breeders Induced ovulators Penile spines (Testosterone) Proestrus (1-2 d) Estrus (5 – 8 d) Recurring …* Diestrus 30 – 70 d Detection of estrus Rubbing against people and inanimate objects Puberty: 6-10 months Vocalizing Season of birth Posturing Weight tree is a sass will have constantly gele xy y hear to the Ecuador countries  Lorenzo Segabinazzi, DVM, MSc, PhD Ross University School of Veterinary Medicine THANK YOU [email protected] VETERINARY.ROSSU.EDU ©2021 Ross University School of Veterinary Medicine. 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