Synchronization means to happen at the same time or to move at same
speed. Synchronization of estrus causes the herd to come in estrus
almost at the same time.
It is used for reproductive management of herd at individual
level or at herd level.
For induction of parturition at the same time we also
synchronize. All animals parturate at same time with difference
of 1-2 days.
Preparation of animal for competition. For example for milk
production we prepare animal for specific period of time by
Help in breeding program specially beef production program.
Methods of Synchronization
There are two methods:
Non hormonal method
If you are going to use non hormonal method then it should be done
20-30 days prior to commencement of breeding season. It includes the
Introduction of Male in a Herd:
If you enter male one month prior to breeding season then
all females will show heat. It is due to pheromones secreted in
urine, feaces, sweat and saliva of male. These are chemicals and act
as hormones. By smelling theses females are affected.
Provision of Artificial Light:
Particularly it works in the mare. The mare is a long day breeder.
It requires extra light. We provide 15- 16 hours extra light per day
for the onset of heat.
By improving nutrition we may get help.
There are three types of hormones used:
Gonadotropin releasing hormone
They may be used as single or in combination
Synthetic or natural preparations of prostaglandins are available
Prostaglandin hormone works in cyclic animals having CL on the
ovary. It will cause the lysis of CL, progesterone level will go
down, feedback mechanism stimulates anterior pituitary and FSH will
be secreted. In case of plain ovary use other hormones.
Prostaglandin and progesterone can be given in combination. Give
progesterone for 10-15 days and then sudden drop in it and give
Cloprostenol is synthetic analogue of PGF2α. It can be used through
intramuscular, intravenous, intrauterine or direct injection in CL
(using specific needle and syringe). 2 ml is dose for intramuscular
rout, 1 ml for intrauterine (1 ml + 9 ml of dextrose solution or
normal saline), and 0.5 ml for CL.
Programs for Synchronization with PGF2α:
There are 4 programs for synchronization on herd level. At
individual level go for rectal palpation, judge CL, if persistent
then give PG to make animal to come in heat. Response time for PG is
within 48-120 hours and average 72 hours. One must be careful after
injection; within 5 days animal shows heat.
Single injection with 5 day breeding program
will palpate all the animals, confirmation of CL
Injection of PGF2α (natural 2 cc and synthetic 4-5 cc)
Confirmation of estrous
(12 hours after standing estrus).
Single injection with 10 day breeding program
Should be implemented at the starts of breeding season
In first 5 days of breeding season animals show the natural estrus;
they will be inseminated.
Animals not showing estrus in first 5 days will not be inseminated
and they are given single
injection of PGF2α.
Confirmation of estrus
AI (12 hours after standing estrus).
Double injection with 10 day breeding program
Inject PGF2α on day 1 to all animals
For next 5 days detection of estrus and proper insemination
PGF2α (second injection) to those which did not show estrus
in first 5 days
In next 5 days detection of estrus and proper insemination
2 injections within 5 day program
injection to all animals in herd to be synchronized and then do not
go for detection of estrus
in next 5 days and without A.I give second
injection to animal at the interval of 11-14 days (14 days
preferred) from the first injection
Detection of estrous and confirmation within 5 days of second
injection and AI
Accuracy of this program is above 80 %. It is mostly used. It
is the best method
animal should be shifted to high plan of nutrition before going for
can go for synchronization after 40-50 days of calving.
There should be accurate estrus detection method.
should be cyclic one (key point for PGF2α)
careful upto 120 hours after giving injection.
Limitations for Use of PGF2α:
be used only in cyclic animals
effective one in proestrus or immediate metestrus
effective upto 7 days post estrus
Other major hormone which can be used is progesterone. It should be
used 15-20 days before the onset of breeding season.
With progesterone basic principle is; first you have to maintain
luteal activity of animal. You have to continue this for 10-12 days
and after 10-12 days suddenly remove the source of progesterone. Due
to sudden removal there will be negative feedback, anterior
pituitary will be stimulated and there will be release of FSH.
Possibility of estrus is 5-7 days after the removal of source. This
can be used by intramuscular, subcutaneous, oral, or intravaginal
Oral dose is 0.5 mg/herd/day. Mix the drugs with vegetable oil and
that oil is mixed in concentrate and given for 10 days. When you
stop; within next 5-7 days following animal will show estrus.
Intravaginal: Progesterone Releasing Intravaginal Device (PRID) and
Control Internal Drug Releasing (CIDR) placed in vagina. Take care
of urination. Special speculum is used. Place near cervix. Gel is
used to lubricate sponge, oil is not used. Lubricate it from side.
Keep it for 7-10 days. Each time sterilize speculum when speculum is
used in large number of animals. Never use oral preparation for
Hormones ECG and PMSG are used for induction of estrus. After
removal of sponge you give ECG 300-400 IU through I/M in animal that
increases the fecundity rate.
It is for induction of estrus. Gonadotropin and gonadotropin like
hormones stimulate the release of FSH and LH. ECG, PMSG are
gonadotropin like hormones.
Estrogen is not good choice for synchronization. This is for estrus
induction. It does not help in formation of follicle. It only
stimulates epithelium of the reproductive system. High dose may
produce the behavioral signs and some mucous. If ovary has mature
follicle then it may help in ovulation.
It is used for induction of estrus but still not good choice.
10-20 mg (1-2 cc of stilbestrol) I/M
This is given in combination with progesterone or dexamethasone for
induction of parturition.