7/16/2019 estrous synchronization in sheep and goat
1/56
1
Estrus synchronization inSheep and Goat
ByDr. T.C.Jangir (2012V22M)
MAJORCREDIT SEMINAR
ON
7/16/2019 estrous synchronization in sheep and goat
2/56
DEFINITIOS:-
ESTRUS: Period of sexual receptivity.
Commonly referred to as Heat
ESTROUS CYCLE: Reproductive cycle of female,
generally defined as period from one estrus to the
next.
ESTROUS CYCLE
7/16/2019 estrous synchronization in sheep and goat
3/56
ESTROUS CYCLE
Seasonally polyestrus:
Cycles occur only during certain times of the year
Long-day breeders:
Cycle when day length increases
Ex: mare
Short-day breeders:
Begin to cycle as day length decreases
Ex: sheep, goats
7/16/2019 estrous synchronization in sheep and goat
4/56
Reproductive parameters of sheep and goat (Jainudeen, et al.
Reproduction in farm animals 7th edition)
Particular sheep goat
Length of estrous cycle
(days)
17
(14-19)
21 (also short cycles)
(18-22)
Duration of estrous (hrs) 24-36 24-48
Time of ovulation 30-36 hrs from begning
of estrous
21-36 hrs from begning
of estrous
7/16/2019 estrous synchronization in sheep and goat
5/56
Considerations for Small Ruminants
seasonal breeding patterns
lack of large-scale application of AI.
In sheep, AI is further impaired by problems in freezing
ram semen and problems in the transcervical deposition
of semen.
7/16/2019 estrous synchronization in sheep and goat
6/56
Endocrine changes during the
oestrous cycle
7/16/2019 estrous synchronization in sheep and goat
7/56
7
7/16/2019 estrous synchronization in sheep and goat
8/56
8
7/16/2019 estrous synchronization in sheep and goat
9/56
7/16/2019 estrous synchronization in sheep and goat
10/56
Trends in harmone concentrations in the peripheral
circulation of the ewe during the oestrous cycle (DavidNoakes ,Veterinary Reproduction and Obstetrics 9th edition)
FSH (ng/ml)
LH (ng/ml)
Estrogens (pg/ml)
Progestrone
(ng/ml)
7/16/2019 estrous synchronization in sheep and goat
11/56
Endocrine changes during the oestrous cycle
in ewe-
Just before the onset of oestrus rise in oestrogens in the
peripheral circulation, particularly oestradiol-17.
This is followed by a sudden surge of LH which reaches a peakabout 14 hours before ovulation; coincidental with this peak is
a rise in FSH.
There is also a second FSH peak 2 days after ovulation.
Prolactin fluctuates throughout the oestrous cycle.
7/16/2019 estrous synchronization in sheep and goat
12/56
Trends in harmone concentrations in the
peripheral circulation of the goat during theoestrous cycle
7/16/2019 estrous synchronization in sheep and goat
13/56
Behavioral signs of estrus
Does
Bleating continuously
Swollen red colored vulva
Flagging of the tail
Frequent urination
Cervical mucus discharge, which causes hairs to stick
together
Restlessness
Mounting other goats andseeking the buck
7/16/2019 estrous synchronization in sheep and goat
14/56
Behavioral signs of estrus
Ewes
The signs of estrus in the ewe are not obvious unless a
ram is present.
As in the doe, the vulva is swollen and redder than usual,and there is a discharge of mucus but is difficult to see in
a ewe with a tail or fleece.
Normal duration will be 24 to 36 hours.
7/16/2019 estrous synchronization in sheep and goat
15/56
Ram has found ewe on heat. She stands still, looking around
at the ram, tail fanning, ears pricked. She is waiting to be
mounted.
7/16/2019 estrous synchronization in sheep and goat
16/56
Ram 'sniff hunting' ewes
7/16/2019 estrous synchronization in sheep and goat
17/56
Estrus detection techniques
Using a teaser ram or buck
Tying an apron made of leather or canvas around thebody of a ram or buck.
Using a teaser with a marking harness
7/16/2019 estrous synchronization in sheep and goat
18/56
7/16/2019 estrous synchronization in sheep and goat
19/56
7/16/2019 estrous synchronization in sheep and goat
20/56
7/16/2019 estrous synchronization in sheep and goat
21/56
Estrus synchronization
Manipulation of the estrous cycle to bring a large
proportion of females in estrus at a pre-determined
time.
7/16/2019 estrous synchronization in sheep and goat
22/56
Introduction
Estrus synchronization (ES) in livestock focuses on themanipulation of either the luteal or the follicular phase
of the estrous cycle.
In does and ewes, the opportunity for control is greaterduring the luteal phase, which is of longer duration and
more responsive to manipulation.
Strategies can be employed to extend the luteal phase by
supplying exogenous progesterone or to shorten this
phase by prematurely regressing existing CL.
7/16/2019 estrous synchronization in sheep and goat
23/56
Why do we need to synchronize estrus?
To facilitate the practice of artificial insemination, eitherfor genetic improvement or to reduce the number oframs/bucks needed to be kept.
To match the period of lambing/kidding with feedavailability or to produce products out-of-season.
Used as an initial step for super-ovulation and
subsequent embryo transfer.
Induction of estrus in ewes/does with silent estrus toshorten the lambing/kidding interval.
7/16/2019 estrous synchronization in sheep and goat
24/56
Disadvantages of synchronized
ovulation
Low conception rates
Cost
Concentrated labor required during breeding and
calving season
E S h i i
7/16/2019 estrous synchronization in sheep and goat
25/56
Estrous SynchronizationMethods
A. Hormonal :
Shortening the luteal phase
PGF2Estrogen
Extending the luteal phase
Long term use of progestrone or progestogen (14-21 days)
B. Non-hormonal :Light,
nutrition,
weaning,
male stimulation
7/16/2019 estrous synchronization in sheep and goat
26/56
Compounds used in estrous
synchronization1. Progesterone
It controls the life of thecorpus luteum ormanipulate circulatingprogesteroneconcentrations thatallows regulation ofoestrus and ovulation(Hansel and Convey,1983).
7/16/2019 estrous synchronization in sheep and goat
27/56
The progesterone or progestagen treatment can be
delivered through-
intravaginal sponge,
CIDR, PRID or
a subcutaneous implant
(Evans and Maxwell, 1987; Ritar et
al., 1989; Freitas et al., 1997).
7/16/2019 estrous synchronization in sheep and goat
28/56
2. Synthetic progestogens
Norgestomet Crestar(implant)
Medroxy acetate
progesterone (MAP)
Melengestrol acetate
(MGA) (oral)
flurogestone acetate (FGA)
7/16/2019 estrous synchronization in sheep and goat
29/56
Steps in CIDR application/loading
7/16/2019 estrous synchronization in sheep and goat
30/56
CIDR application/loading
7/16/2019 estrous synchronization in sheep and goat
31/56
CIDR application/loading
7/16/2019 estrous synchronization in sheep and goat
32/56
CIDR application/loading
7/16/2019 estrous synchronization in sheep and goat
33/56
Intravaginal Sponges
Intravaginal sponges have
been the traditional
treatment of choice for ES
in small ruminants, during
the breeding and anestrusseasons. They are
impregnated with -
A. progestagens or
B. natural progesterone
7/16/2019 estrous synchronization in sheep and goat
34/56
Cont
In sheep, progestagen
impregnated intravaginal
sponges or CIDRs are
inserted intravaginally for
1214 days. Ewes show oestrus
approximately 48 h after
device removal.
7/16/2019 estrous synchronization in sheep and goat
35/56
In goats, progestagen
impregnated sponges are
inserted intravaginally for 1618 days, whilst CIDRs are left
in place for 1821 days.
The majority of does will bein oestrus approximately 48 h
after removal (Wheaton et al.,
1993).
At the time of removal,
animals are administered
eCG/PMSG.
Intra-vag na sponges or estrus n uct on
7/16/2019 estrous synchronization in sheep and goat
36/56
Intra-vag na sponges or estrus n uct on
and synchronization (prepaired at CSWRI)
Developed indigenously for
estrus induction and
synchronization in sheep
and goats.
A solution of progesterone
(0.175 g/ml) was prepared
in ethanol and each sponge
was loaded with 2 mlsolution.
7/16/2019 estrous synchronization in sheep and goat
37/56
Intra-vaginal sponges for estrus induction
and synchronization (CSWRI) Protocol
7/16/2019 estrous synchronization in sheep and goat
38/56
7/16/2019 estrous synchronization in sheep and goat
39/56
7/16/2019 estrous synchronization in sheep and goat
40/56
7/16/2019 estrous synchronization in sheep and goat
41/56
prostaglandin or its analogue
The primary luteolytic factor in ruminants is the
prostaglandin F2 ( McCracken et al., 1972); thus,
administration of exogenous PGF2 or its analogues
is useful for inducing luteolysis (Douglas andGinther, 1973).
The main advantage of prostaglandin treatment is
the possibility of administration by intramuscular
injection.
7/16/2019 estrous synchronization in sheep and goat
42/56
ProstaglandinsIntramuscular injection requires higher dosage than
intrauterine injection because of the short half-life ofthe substance.
Half-life about 2-3 minutes; approximately 90%deactivated in single passage through body.
7/16/2019 estrous synchronization in sheep and goat
43/56
The inconveniences of using
7/16/2019 estrous synchronization in sheep and goat
44/56
The inconveniences of using
PGF2 are-
1.The CL can be responsive to PGF2 from day 3 of the
oestrous cycle (Rubianes et al.,2003) to the day of natural
luteolysis; therefore, animals should contain an active CL.
2. The second inconvenience is that the 910-day protocol is
effective in synchronising oestrus, but fertility of the ewes at
first mating is only about 70%, significantly lower than that
after progestagen treatments and natural services (Boland et
al., 1978; Godfrey et al., 1999).
7/16/2019 estrous synchronization in sheep and goat
45/56
A protocol developed for synchronization of estrus in
cycling native ewes at CSWRI includes administration of
two intramuscular injections of PGF2 7.5 mg at 10 days
interval.
7/16/2019 estrous synchronization in sheep and goat
46/56
GnRH agonists Hypothalamus hormone
Release of FSH, LH
Buselerin (Cystorelin, Factrel, Fertagyl,
OvaCyst, Receptal etc.)
7/16/2019 estrous synchronization in sheep and goat
47/56
7/16/2019 estrous synchronization in sheep and goat
48/56
Estrogens Estradiol conjugates
Estradiol valerate
Estradiol bazoate
Estradiol cypionateGonadotropins
eCG or PMSG
FSHhCG
7/16/2019 estrous synchronization in sheep and goat
49/56
Melatonin and Photoperiodicity
Discovered by Lerner et al. (1958).
Photoperiodic information is received at the level of the
retina and transmitted, via a multi-step neural pathway, tothe pineal gland, where the message modulates the
rhythm of melatonin secretion (Bittman et al., 1983).
7/16/2019 estrous synchronization in sheep and goat
50/56
Diagram on the role of photoperiod and pineal gland onsteroid feedback and seasonal estrous cycles.
7/16/2019 estrous synchronization in sheep and goat
51/56
Cont It has been reported that in anoestrous ewes a
significant increase of GnRH secretion after 40 days andhigh GnRH and LH pulsatility occurs after 74 days of
melatonin treatment (Vigui et al., 1995).
And it is done by reducing tyrosine hydroxylase activity and,therefore, the secretion of dopamine in the median
eminence (Vigui et al., 1997).
Thereby, implants cause a short day-like response bylengthening the duration of the melatonin signal (Malpaux
et al., 1997).
7/16/2019 estrous synchronization in sheep and goat
52/56
Cont
The implants contain 18 mg of melatonin and are
designed to maintain high plasma melatonin
concentrations for at least 60 days, although most of
them continue releasing the hormone for over 100 days
(Forcada et al., 2002).
The implant release maintains daytime plasma
concentrations of melatonin >100 pg/mL, in both ewes
(Forcada et al., 1995) and goats (Delgadillo et al., 2001).
The male effect
7/16/2019 estrous synchronization in sheep and goat
53/56
The male effect
The male can be used to stimulate estrus activity of
females that have been previously isolated from males
for a period of 34 weeks.
The so-called male effect is a technique to stimulate thesexual activity in seasonally anovulatory goats ( Pellicer-
Rubio et al., 2007).
After the period of separation, the male animal is
suddenly introduced to the group of females.
7/16/2019 estrous synchronization in sheep and goat
54/56
In response to introduction of the male, ewes/does secrete
increasing amounts of LH and FSH, which result in ovulationafter 2 or 3 days of male introduction.
In cyclic goats, highest frequency of estrus was observed
within the first 3 days of buck introduction.
7/16/2019 estrous synchronization in sheep and goat
55/56
The following factors affect response to male
introduction:
High sexual activity or libido test scores of male
High plane of nutrition of female
The longer lambs/kids have been weaned from ewes/does,
the better the response of the ewes/does.
7/16/2019 estrous synchronization in sheep and goat
56/56
Top Related