Estrus Estrus Induction,Principle,MethodsInduction,Principle,Methods

and Applicationsand Applications

Ankesh KumarAnkesh Kumar Roll No. P-Roll No. P-

17931793

Reproductive hormonesReproductive hormones OriginateOriginate

– HypothalamusHypothalamus– PituitaryPituitary– GonadsGonads– UterusUterus– PlacentaPlacenta

CauseCause– Release of other hormones (releasing hormones)Release of other hormones (releasing hormones)– Stimulate gonads (gonadotropins)Stimulate gonads (gonadotropins)– Sexual promotion (steroids)Sexual promotion (steroids)– Pregnancy maintenancePregnancy maintenance– LuteolysisLuteolysis

Biochemical classificationBiochemical classification – PeptidesPeptides– GlycoproteinsGlycoproteins– SteroidsSteroids– ProstaglandinsProstaglandins

The most important hormones The most important hormones influencing ovarian activityinfluencing ovarian activity

Hormone Biochemical classification

Source Action in female Effect on ovary

GnRH Decapeptide Hypothalamus Release FSH and LH Follicular develop-ment; ovulation

LH Glycoprotein Pituitary Stimulates ovulation and P4 secretion

Formation of CL

FSH Glycoprotein Pituitary Follicular development, E2 synthesis

Development of follicles

Progesterone Steroid CL, placenta Maintenance of pregnancy Inhibits GnRH release

Estradiol Steroid Follicle, placenta Sexual behavior -

hCG Glycoprotein Chorion ovarian P4 synthesis -

eCG Glycoprotein Chorion Formation of accessory CL’s -

PGF2Prostaglandin Endometrium Destruction of CL Luteolysis

Inhibin Glycoprotein Granulosal cells Inhibits FSH secretion Inhibits follicle development

The estrus cycle of the cow The estrus cycle of the cow (Senger, 2003)(Senger, 2003)

Methods for inducing estrus and synchronizing Methods for inducing estrus and synchronizing ovulationovulation

Method of inducing ovulation are needed for treatment of Method of inducing ovulation are needed for treatment of anoestrus and synchronization of oestrus cycle for timed anoestrus and synchronization of oestrus cycle for timed AI(TAI).AI(TAI).

Methods with heat detectionMethods with heat detection– Progestin application (MGA, PRID, CIDR)Progestin application (MGA, PRID, CIDR)– Deslorelin implant (GnRH agonist)Deslorelin implant (GnRH agonist)– ProstaglandinProstaglandin (single or Double dosage PGf (single or Double dosage PGf22 treatment) treatment)

Timed inseminationTimed insemination– Heatsynch (GnRH - PGfHeatsynch (GnRH - PGf22 – ECP) – ECP) – Ovsynch (GnRH - PGfOvsynch (GnRH - PGf22 – GnRH) – GnRH)– CosynchCosynch– Provsynch (PGfProvsynch (PGf22 – PGf – PGf22 – GnRH - PGf – GnRH - PGf22 – GnRH) – GnRH)

starts 35 days after parturitionstarts 35 days after parturition

ESTROUS SYNCHRONIZATIONESTROUS SYNCHRONIZATION A management technique that makes A management technique that makes

use of hormones to control or reschedule use of hormones to control or reschedule the estrous cyclethe estrous cycle

Hormones associated with reproductionLH & FSH

Progesterone Estrogen

Prostaglandin

Why synchronize?Why synchronize? Group females for parturition Group females for parturition

(calving interval)(calving interval) Shorten breeding seasonShorten breeding season Reduce estrus detectionReduce estrus detection

ADVANTAGES OF IMPLEMENTING A SYNCHRONIZATION ADVANTAGES OF IMPLEMENTING A SYNCHRONIZATION PROGRAMPROGRAM

Calves produced early in season will wean heavier Calves produced early in season will wean heavier because they are olderbecause they are older

Cows require 40-60 days to recover from calving Cows require 40-60 days to recover from calving before next breedingbefore next breeding– Cows that bred earlier have better chance of maintaining Cows that bred earlier have better chance of maintaining

365 d calving interval the next year365 d calving interval the next year

Basis for Synchronization of Basis for Synchronization of EstrusEstrus

Manipulate life span of CLManipulate life span of CL

Manipulate growth of follicles and Manipulate growth of follicles and timing of ovulationtiming of ovulation

MethodMethod TradenaTradenameme

UtilizationUtilization

GonadotropinsGonadotropins CystorelinCystorelinFertagylFertagyl

Mature femalesMature females

ProstaglandinsProstaglandins EstrumateEstrumateLutalyseLutalyseProstamatProstamatee

Cycling femalesCycling females

ProgestinsProgestins MGAMGACIDRCIDR

Pre-pubertal Pre-pubertal heifersheifersPost-partum orPost-partum orAnestrous Anestrous femalesfemales

Synchronization Methods

Synchronization MethodsSynchronization Methods Gonadotropins(GnRH protocols)Gonadotropins(GnRH protocols)

Naturally occurring hormone that Naturally occurring hormone that stimulates the release of LH and FSH stimulates the release of LH and FSH that stimulates follicular developmentthat stimulates follicular development

Protocols include Ovsynch and Protocols include Ovsynch and CosynchCosynch

Synchronization methodsSynchronization methodsProstaglandinsProstaglandins

– Naturally occurring hormone that causes Naturally occurring hormone that causes regression of the CL (luteolysis) and regression of the CL (luteolysis) and decreases progesterone secretion which decreases progesterone secretion which results in a return to estrusresults in a return to estrus

– Can expect estrus within two days Can expect estrus within two days following injectionfollowing injection

– Protocols include PGF one-shot method Protocols include PGF one-shot method and PGF two-shot methodand PGF two-shot method

Synchronization methodsSynchronization methodsProgestinsProgestins Form of progesterone that extends Form of progesterone that extends

the period of time progesterone is the period of time progesterone is present and prevents animal from present and prevents animal from coming into heatcoming into heat

Protocols include MGA+prostaglandin Protocols include MGA+prostaglandin and CIDR and CIDR

Synchronization methods: Synchronization methods: drug trade names and drug trade names and

effectivenesseffectivenessMethodMethod Trade Trade

namenameFemale “type” for Female “type” for drug effectivenessdrug effectiveness

ProstaglandinsProstaglandins Lutalyse*Lutalyse*Estrumate*Estrumate*Prostamate*Prostamate*EquimateEquimate∞∞

PregmaPregma

*Cycling cows or heifers*Cycling cows or heifers∞∞Cycling maresCycling mares

ProgestinsProgestins MGA*MGA*CIDR*CIDR*RegumateRegumate∞∞

*Cycling cows or heifers*Cycling cows or heifers*Anestrous cows or heifers*Anestrous cows or heifers∞∞MaresMares

* Cattle ∞Equine ^Swine

Synchronization methods:Synchronization methods:drug trade names and drug trade names and

effectivenesseffectivenessMethodMethod Trade Trade

namenameFemale “Type” for Female “Type” for drug effectivenessdrug effectiveness

Gonadotropin Gonadotropin Releasing Releasing HormonesHormones

Receptal*Receptal*Gynarich*Gynarich*Ovulanta Ovulanta injinj∞∞

*Postpartum cows*Postpartum cows*Anestrous cows*Anestrous cows∞∞Cycling maresCycling mares

PlacentalPlacentalGonadotropinsGonadotropins

PG600^PG600^ ^Peri-pubertal gilts ^Peri-pubertal gilts

* Cattle ∞Equine ^Swine

One Injection of PGFOne Injection of PGF AdvantagesAdvantages

– Useful for detection Useful for detection of estrus in heifers of estrus in heifers and cowsand cows

– Decreased drug costDecreased drug cost– Limited animal Limited animal

handlinghandling

LimitationsLimitations– 10-25% of females 10-25% of females

may not be may not be detected in estrus detected in estrus during days 0 to 10during days 0 to 10

– Poor degree of Poor degree of synchrony on synchrony on females that return females that return to estrusto estrus

– Must have CLMust have CL– Length of estrus Length of estrus

detectiondetection– AbortionAbortion

Two Injections of PGFTwo Injections of PGF AdvantagesAdvantages

– Useful for detection Useful for detection of estrus in heifers of estrus in heifers and cowsand cows

– Tighter synchrony Tighter synchrony than one injection than one injection methodmethod

– Can use fixed Can use fixed insemination time insemination time after 2after 2ndnd injection injection

LimitationsLimitations– Females must have Females must have

functional CLfunctional CL– Length of estrus Length of estrus

detectiondetection– Administration of Administration of

PGF will cause PGF will cause abortion in abortion in pregnant animalspregnant animals

MGA and ProstaglandinMGA and Prostaglandin AdvantagesAdvantages

– Proven system for Proven system for heifersheifers

– Inexpensive methodInexpensive method– Can hasten cyclicity Can hasten cyclicity

in anestrous in anestrous femalesfemales

LimitationsLimitations– Length of programLength of program– Must have appropriate Must have appropriate

feeding space to allow feeding space to allow efficient consumptionefficient consumption

– Estrus synchronization Estrus synchronization may be variablemay be variable

– Must ensure uniform Must ensure uniform daily consumption of daily consumption of feed supplement prior feed supplement prior to and during oral to and during oral administration of MGAadministration of MGA

CIDRCIDR AdvantagesAdvantages

– Useful for detection of Useful for detection of estrus in heifers and estrus in heifers and cowscows

– Induces cyclicity in a Induces cyclicity in a percentage of percentage of anestrous cattleanestrous cattle

– High pregnancy ratesHigh pregnancy rates– Treatment of follicular Treatment of follicular

cystcyst– Improve oocyte qualityImprove oocyte quality– Treatment of repeat Treatment of repeat

breederbreeder

LimitationsLimitations– Possible retention Possible retention

failure of CIDRfailure of CIDR– Cost per treatment Cost per treatment

may be higher than may be higher than other methodsother methods

– An additional day of An additional day of processing for processing for hormone treatment hormone treatment would be required would be required to facilitate fixed to facilitate fixed time AItime AI

Cost $9.00/head

Heat-SynchECP at 48hrs

GnRH-PGF BASED SYNCHRONIZATION GnRH-PGF BASED SYNCHRONIZATION OPTIONSOPTIONS

THE SELECT SYNCH SYSTEM

COSYNCH/OVISYNCHCOSYNCH/OVISYNCH

I. Ovisynch is a fixed – time AI synchronization protocolII. Average pregnancy rate to ovisynch is 30 to 40%III. Ovisynch pregnancy rate can be significantly improved if cows are set-up

or pre-synchronized .IV. Ovisynch, pregnancy rates are maximized if the early heat are visually

detected and bred using the AM/PM rule

GnRH GnRH AdvantagesAdvantages

– Higher and tighter Higher and tighter rate of estrus rate of estrus synchrony synchrony compared to PGF compared to PGF protocolsprotocols

– Allows for estrus Allows for estrus detection or timed detection or timed AIAI

LimitationsLimitations– Higher cost due to Higher cost due to

hormone injectionshormone injections– Increase of time Increase of time

and laborand labor– Not recommended Not recommended

for use in heifersfor use in heifers

Synchronization in the MareSynchronization in the Mare Feeding mare altrenogest for 15 day induces oestrus Feeding mare altrenogest for 15 day induces oestrus

about 3 days after progesterone withdrawal and about 3 days after progesterone withdrawal and satisfactory fertility can be obtained by matting on satisfactory fertility can be obtained by matting on alternate days during oestrusalternate days during oestrus

Diestrum mare will respond to a single injection of Diestrum mare will respond to a single injection of PGF2alpha by exhibiting oestrus within 3 to 5 days. PGF2alpha by exhibiting oestrus within 3 to 5 days.

In randomly cycling mare, oestrus can be synchronized In randomly cycling mare, oestrus can be synchronized by a regime that involve two dose of PGF2 alpha and by a regime that involve two dose of PGF2 alpha and two dose of hCGtwo dose of hCG

Synchronization in the SowSynchronization in the Sow Progesterone (Altrenogest) fed for 14 to18 days is effective in Progesterone (Altrenogest) fed for 14 to18 days is effective in

synchronizing oestrus in cycling gilt and sow Normally oestrus synchronizing oestrus in cycling gilt and sow Normally oestrus begins on 4begins on 4thth or 5 or 5thth day after progesterone withdrawal day after progesterone withdrawal

PGF is not useful for synchronizing in cycling swine because CL PGF is not useful for synchronizing in cycling swine because CL do not respond to PGF during 12 or 13 day of oestrus cycledo not respond to PGF during 12 or 13 day of oestrus cycle

Potential way of synchronizing oestrus in swine is to inject 500 Potential way of synchronizing oestrus in swine is to inject 500 to 1000 IU OF hCG on day 12 of oestrus cycle ,then inject PGF to 1000 IU OF hCG on day 12 of oestrus cycle ,then inject PGF about 3 week later.about 3 week later.

Noncycling gilts can be synchronized with P.G. 600 (400 IU eCG Noncycling gilts can be synchronized with P.G. 600 (400 IU eCG and 200 IU hCG)and 200 IU hCG)

Synchronization in the EweSynchronization in the Ewe

Progesterone for 12-21 Progesterone for 12-21 days with eCG given near days with eCG given near the end of progesterone the end of progesterone treatment &treatment &

animal will be in estrus animal will be in estrus within 2-4 days within 2-4 days

Most common protocols Most common protocols use either use use either use prostaglandins or CIDRprostaglandins or CIDR

Acyclic Cyclic Progesterone(Pessary for 18-21 days)+eCG (on day of pessary removal) & animal will be in estrus within 2-3 day

Two PGF injection (11-12 days apart)

ThankThank YouYou

Estrus synchronization Estrus synchronization protocolsprotocolsPROSTAGLANDIN

S

LIMITATIONSI.Fixed time insemination after single and double injection of PGF alone seldom yields acceptable result and in general not recommended.II.A major limitation of PGF is that it only works in cyclic animals.

Effect of select synch or 2PGF injection 14 days apart on estrus detection, conception and pregnancy rate in anoestrus beef cows1. Major benefit of the select synch are simplicity and tight synchrony of

estrus2. Most animal display standing estrus2 to 4 day after the PGF injection

GnRH-PGF BASED SYNCHRONIZATION GnRH-PGF BASED SYNCHRONIZATION OPTIONSOPTIONS

THE SELECT SYNCH SYSTEM

THE MGA-PGF SYNCHRONIZATION THE MGA-PGF SYNCHRONIZATION PROTOCOLPROTOCOL

I. The-PGF

COSYNCH/OVISYNCHCOSYNCH/OVISYNCH

I. Ovisynch is a fixed – time AI synchronization protocolII. Average pregnancy rate to ovisynch is 30 to 40%III. Ovisynch pregnancy rate can be significantly improved if cows are set-up

or pre-synchronized .IV. Ovisynch, pregnancy rates are maximized if the early heat are visually

detected and bred using the AM/PM rule

Effect of select synch or 2PGF injection 14 days apart on estrus detection, conception and pregnancy rate in cycling cows