estrus cycle
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its my undergraduation level studyTRANSCRIPT
بسم الله الرحمن بسم الله الرحمن الرحيمالرحيم
ورحمته ورحمته السالُم� َع�ليڪم السالُم� َع�ليڪم اللهالله
Under Kind Supervision Under Kind Supervision
Dr. K.B. MirbaharDr. K.B. MirbaharProfessor Professor
Department of Animal ReproductionDepartment of Animal Reproduction
By:Sajid Aziz Samo
2K8-AR-156
ESTRUS CYCLEThe recurrent, restricted period of sexual receptivity in female mammals,
Marked by intense sexual urge.
Or
The female reproductive system of most mammals exhibits a rhythmical changes called the estrus cycle.
To understand the different parts of the estrous cycle.
To understand the hormonal changes during the estrous cycle.
To understand how the estrous cycle coordinates the events of
female reproduction so it can be successful.
LEARNING OBJECTIVES
Proestrus: ( Period Of Preparation ) Characterized by stimulation of follicular growth by FSH
Estrus: ( The Period Of Desire ) Characterized by psychic manifestations of heat
Metestrus: ( Postestrus ) Characterized by the sudden cessation of heat
Diestrus: ( The Final Period )
PERIODS OF THE ESTRUS CYCLE
ANESTRUS:
Female is not cycling (No expression of heat over time)
Cow has a 21 Day Estrous Cycle: Day 0 first Day of Standing Heat
Tertiary follicle(s) and oocytes undergo final maturation Estrogen levels
Female starts to become receptive - Estrogen prepares uterus and oviducts for sperm transport and fertilization - Estrogen initiates uterine changes for later embryo development
(Day 17-20 (Follicular Phase)
Prior to estrus, CL is undergoing regression, progesteronelevels fall below 1 ng/mL which allows final follicular development
One dominant follicle - Graafian StageStimulated to final maturation by FSH and LH
Estrogen
Smooth muscle contractions and cilia movement
Uterine glands and oviduct secretion
PROESTRUS:
CYCLIC CHANGES IN OVARIAN CYCLIC CHANGES IN OVARIAN STRUCTURESTRUCTURE
PROESTRUS
( Day of Standing heat! Day 0 of estrous cycle Lasts 12 to 20 hours in cow)
Estrogen from the Graafian follicle stimulate increase in GnRHwhich stimulates increase in LH
GnRH increases to cause a large increase in LH (surge release) Ovulation occurs during estrus in ewe, sow and mare but
metestrus in cow
Following ovulation - LH stimulates development of luteal cellsfrom the granulosa and thecal cells of the ovulated follicle wall.
Theca and granulosa cells luteinize by LH stimulation to differentiate in luteal cells
ESTRUS:FEMALE IN HEAT
High estrogens cause LH surge
LH surge causes ovulation
LH surge initiates corpus luteum formation
SIGNS OF ESTRUS PERIOD
1. Restlessness
2. Mounting
3. Swollen vulva
4. Bawling
5. Discharge of the watery mucosa
ESTRUS
Estrogen levels have decreased
Corpus luteum is forming
Progesterone levels start to
Progesterone begins preparing the uterus for the embryo Embryo partially develops in the oviduct and moves into the uterus
(Day 2-4 of Estrous Cycle)
In cow, ovulation occurs after the end of estrus
Graafian follicle has ovulated
Developing from Corpus Hemorrhagicum
Second increase in FSH occurs to stimulate anotherwave of follicular development
Moves into uterus on Day 4 - 5 depending on species
METESTRUS:
Maximum corpus luteum size High progesterone levels inhibit final follicular development, ovulation and estrus
Embryo continues to develop in the uterus Embryo signals the uterus it is present - no CL regression If embryo is not present - uterus releases PGF2a to cause CL regression If CL regresses, progesterone in blood decreases and Graafian follicle(s) begin final development that occurs in proestrus for ovulation at estrus.
(Day 5 - 17 of Estrous Cycle)
Mature at Day 12 of estrous cycle
Inhibits final maturation of follicle and estrus Negative feedback on GnRH
Estrous Cycle starts over!!!!
DIESTRUS:
HORMONAL PROFILES DURING THE ESTROUS CYCLE
ng = nanogram 10-9 grams LH, FSH, Progesteronepg = picogram 10-12 grams Estrogen, PGF2a
Follicle will become atretic and regress as a new follicle grows to ovulate with CL regression
Increases for CLregression Second increase of FSH for
follicle development. Inhibinis low as is progesterone
When progesterone is less than 1 ng/ml it usually means the cowhas regressed the CLand is coming into heatduring the estrous cycle
Estrus
LH surgefor ovulation
First FollicularWave
Second FollicularWave
Estrus ESTRUS
MARE
PHASES OF THE ESTROUS CYCLE
FOLLICULAR: (from the regression of CL to ovulation) 2-3 days in ewe and 3-4 days in cow
LUTEAL: (period of corpus luteum activity)
Phase of the female estrous cycle when she is underestrogen stimulation
Proestrus and Estrus
Phase of the female estrous cycle when she is underprogesterone stimulation
Metestrus and Diestrus
CYCLIC CHANGES IN VAGINAL CYCLIC CHANGES IN VAGINAL CELL TYPESCELL TYPES
Estrus Diestrus I Diestrus II Proestrus
SPECIES VARIATION IN ESTROUS CYCLE CHARACTERISTICS
ESTROUS CYCLE EWE SOW COW MARE
LENGTH OF ESTROUS CYCLE
14 - 19 DAYS
18 - 22 DAYS
18 - 24 DAYS
16 - 24 DAYS
LENGTH OF ESTRUS
24 - 36 HOURS
48 - 72 HOURS
12 - 19 HOURS
2 - 11 DAYS
TIME OF OVULATION
24 - 36 HOURS AFTER THE ONSET OF ESTRUS
35 - 45 HOURS AFTER THE ONSET OF ESTRUS
10 - 11 HOURS AFTER THE END OF ESTRUS
1 - 2 DAYS BEFORE THE END OF ESTRUS
TIME OF AI
12 - 18 HOURS AFTER THE ONSET OF ESTRUS
16 - 14 HOURS AFTER THE ONSET OF ESTRUS AND AGAIN 8 - 24 HOURS LATER
7 - 18 HOURS AFTER ONSET OF ESTRUS
SECOND DAY AND EVERY OTHER DAY IN ESTRUS
PRESENTED BY.PRESENTED BY.
SAJID AZIZ SAMOSAJID AZIZ SAMOREG. NO. 2K8-AR-156REG. NO. 2K8-AR-156