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SYNCHRONIZATION OF ESTRUS AND OVULATION IN
POSTPARTUM ACYCLIC CROSSBRED COWS
By
N.RAMALAKSHMI B.V.Sc. & A.H.
TVM/13-49
Thesis Submitted to the
SRI VENKATESWARA VETERINARY UNIVERSITY
In partial fulfillment of the requirements
For the award of the degree of
MASTER OF VETERINARY SCIENCE
In the faculty of Veterinary Science
(VETERINARY GYNAECOLOGY AND OBSTETRICS)
DEPARTMENT OF VETERINARY GYNAECOLOGY AND OBSTETRICS
COLLEGE OF VETERINARY SCIENCE
SRI VENKATESWARA VETERINARY UNIVERSITY
TIRUPATI – 517 502 [A.P.] INDIA
NOVEMBER, 2015
ii
CERTIFICATE
Dr. N. RAMALAKSHMI, (TVM/13-49) has satisfactorily prosecuted
the course of research and that the thesis entitled “SYNCHRONIZATION
OF ESTRUS AND OVULATION IN POSTPARTUM ACYCLIC
CROSSBRED COWS” submitted is the result of original research work and
is of sufficiently high standard to warrant its presentation to the examination.
I also certify that the thesis or part thereof has not been previously submitted
by her for a degree of any university.
Date : Place : Tirupati
(Dr. M.SRINIVAS) Chairman of Advisory Committee
Associate Professor Department of Veterinary Gynaecology
and Obstetrics NTR College of Veterinary Science
Gannavaram 521101 [A.P.]
iii
CERTIFICATE
This is to certify that the thesis entitled “SYNCHRONIZATION OF
ESTRUS AND OVULATION IN POSTPARTUM ACYCLIC
CROSSBRED COWS” submitted in partial fulfillment of the requirements
for the degree of Master of Veterinary Science (Veterinary Gynaecology and
Obstetrics) of the Sri Venkateswara Veterinary University, Tirupati, is a
record of the bonafide research work carried out by N. RAMALAKSHMI
(TVM/13-49) under our guidance and supervision. The subject of the thesis
has been approved by the Student’s Advisory Committee.
No part of the thesis has been submitted by the student for any other
degree or diploma. The published part has been fully acknowledged. All
assistance and help received during the course of the investigations have been
duly acknowledged by the author of the thesis.
(Dr. M. SRINIVAS) Chairman of the Advisory Committee Thesis approved by the Student’s Advisory Committee CHAIRMAN : Dr. M. SRINIVAS ____________________
Associate Professor Department of Veterinary Gynaecology and Obstetrics NTR College of Veterinary Science
Gannavaram– 521101. MEMBER : Dr. K. MOULI KRISHNA ____________________ Professor and University Head
Department of Veterinary Gynaecology and Obstetrics College of Veterinary Science Tirupati – 517502.
MEMBER : Dr. B. SREEDEVI ____________________ Professor
Department of Veterinary Microbiology College of Veterinary Science Tirupati – 517502 .
iv
TABLE OF CONTENTS
Chapter No Title Page No
I INTRODUCTION 1-2
II REVIEW OF LITERATURE 3-35
2.1 Estrus synchronization 3
2.1.1 Ovsynch Protocol 6
2.1.2 Ovsynchwith PRID protocol 11
2.1.3 PRID with PG protocol 15
2.2 Estrus induction efficiency 21
2.2.1 Estrus Response 21
2.2.2 Duration of estrus 22
2.2.3 Intensity of estrus 23
2.3 Serum progesterone assay 23
2.4 Effect of estrus synchronization protocols on conception rate
27
2.4.1 Breeding at FTAI 27
2.4.2 Conception Rates 28
III MATERIALS AND METHODS 36-40
3.1 Experimental animals 36
3.1.1 Selection of Animals 36
3.2 Design of the study 36
3.3 Evaluation of estrus 37
3.4 Serum progesterone assay 37
3.5 Fertility 40
3.6 Statistical analysis 40
IV RESULTS 41-48
4.1 Estrus induction efficiency 41
v
4.1.1 Estrus response 41
4.1.2 Duration of estrus 41
4.1.3 Intensity of estrus 41
4.2 Serum progesterone assay 42
4.3 Fertility 43
4.3.1 First service conception rate 43
4.3.2 Second service conception rate 43
4.3.3 Overall conception rate 43
V DISCUSSION 49-59
5.1 Estrus induction efficiency 49
5.1.1 Estrus Response 49
5.1.2 Duration of Estrus 51
5.1.3 Intensity of Estrus 51
5.2 Serum progesterone assay 52
5.3 Fertility 54
VI SUMMARY 60-62
LITERATURE CITED 63-74
vi
LIST OF FIGURES
FIGURE NO PARTICULARS Page No.
1 Image showing TRIU-B device applicator 38
2 Image showing applicator and TRIU-B device 38
3 Insertion of TRIU-B device 39
4 Clipped tail of TRIU-B device 39
5 Withdrawal of TRIU-B device 39
6 Comparison of estrus response 45
7 Comparison of intensity of estrus 45
8 Comparison of duration of estrus 45
9 Comparision of mean serum progesterone
concentrations (ng/ml) in various synchronization
protocols on the day of initiation of treatment day ‘0’.
47
10 Comparision of mean serum progesterone
concentrations (ng/ml) in various synchronization
protocols on the day of AI.
47
11 Comparison of conception rates 48
vii
LIST OF TABLES
TABLE
NO
TITLE PAGE NO
1 Effect of synchronization on estrus induction 44
2 Analysis of variance for duration of estrus 44
3 Serum progesterone (Mean±SE) on day ‘0’ and on day
of AI
46
4 Analysis of variance for means (±SE) of serum
progesterone on day ‘0’ and day of AI
46
5 Fertility response in crossbred acyclic cows
synchronized with 3 different protocols
48
viii
Acknowledgments
I thank the God Almighty for showering his abundant blessings on me
which made me to accomplish the task.
I feel it a great privilege for having worked under the guidance of
Dr. M. Srinivas, Associate Professor, Department of Veterinary Gynaecology and
Obstetrics, NTR College of Veterinary Science, Gannavaram for his continuous
help, valuable guidance and endless encouragement during the course of
investigation. The untiring interest, critically going through the manuscript and
also spending time in correction, execution, compilation and preparation of the
thesis are invaluable.
I accord my sincere thanks to Dr. K. Mouli Krishna, Professor and
University Head, Department of Veterinary Gynaecology and Obstetrics, College
of Veterinary Science, Tirupati and member of Advisory Committee for his
guidance, deliberate counsel and help extended during presentation of thesis.
I am extremely thankful to Dr. B. Sreedevi, Professor, Department of
Veterinary Microbiology, College of Veterinary Science, Tirupati and member of
Advisory Committee for her suggestions and cooperation during presentation of
thesis.
I am greatly indebted and extend to my sincere thanks to
Dr. G. Suman kumar, Veterinary Assistant Surgeon, Masters in Veterinary
Gynaecology and Obstetrics, for his whole hearted co-operation and constant
encouragement at all stages of my work.
I wish to extend my gratitude to Dr. K. VeeraBrahmaiah, Professor and
Dr. Allu Teja, Assistant Professor, Department of Veterinary Gynaecology and
Obstetrics, College of Veterinary Science, Tirupati for their timely help, unstinted
ix
cooperation, constant encouragement and affection rendered during the period of
my study.
I wish to convey my sincere thanks to my seniors Dr. G. Padmanabham,
Dr. Y.Pavani, Teaching Assistant and Dr. Jaganath reddy, Teaching Assistant,
Dr. Vishal, Ph.D, Department of Veterinary Gynaecology and Obstretics, Dr.
Shruthi from Department of Veterinary Pathology for her wonderful love, support
and affection towards me, Dr. Jyothi sri from Department of Veterinary
Parasitology and Dr. Radhika, Dr. Lahari, Dr. Sudheer from Department of
Microbiology, Dr. Dhayana from Department of Veterinary Anatomy and Dr.
Roshan baig from Department of Veterinary Animal Husbandary and Extension,
College of Veterinary Science, Tirupati for their constant suggestions and
encouragement during the period of study.
It is the correct time to express my heartfelt thanks to my affectionate
colleagues Dr. A. Geetha reddy, Dr. P. Kalyan Venkatesh, Dr. Yedukondalu, Dr.
Hemkunar, Dr. Praveen kumar, Dr. Satish and Dr. Praveen Raj and seniors and
friends of veterinary Dr. Y.Prathiba, Dr. SivaNagaraju, Dr. Divya,
Dr.Sivajyothi, Dr. Indira, Dr. Mohan kishore, Dr. Gopikrishna, Dr.G. Srinivas,
Dr. Vamsikrishna, Dr. Chandrasekhar naik, Dr.Manoj, Dr. Sudharshan,
Dr.Sudhakar, Dr. Mahesh, Dr. Deepa, Dr. Asha Kumari, Dr. Sailu madhuri, Dr.
Sudheer, Dr. Yeswanth, Dr. Rama Chandra rao, Dr. Ramu, Dr.Prasanna and Dr.
Praveen(chano) for their affection, moral support, cheerful and generous help and
pleasant company.
I express warmest thanks to my juniors Dr.Anil, Dr.Ravikanth, Dr.
Preethi, Dr. Harini, Dr. Prasuna, Dr. Praveen Kumar, Dr.Hanuman, Dr. Harish,
Dr. Tejaswi, Dr. Prakash, Dr. Suvarna, Dr.Harshini, Dr. Sravani Pragna and
Shoba for their co-operation and affectionate help during my research work.
Lots of thanks to my dalzz lovely cute schoolmates Dr. Meena, Sowmya,
Dr.Sireesha, Gaddipati Anusha (gaddi) , Naga raju and Raghu vamsi for their pure
love and affection till today
x
I thank Mrs.Syamalamma, Mrs.Rajyalakshmi, Mr.Sekhar,
Mr.Chengalarayulu, Mr. Anand, Mr. Ramana and Mrs. Danamma for their
cooperation and affectionate help during my research work.
I thank Sri Venkateswara Veterinary University for providing monetary
support in the form of stipend to prosecute my post graduation study.
It is time to surface out my profound love and affectionate gratitude to my
beloved parents Sri. N.Anjana Rao and Smt.K. Rani and my sisters younger one
Dr. N. Alekhya and youngest Ms. Srilekha who constantly guided and moulded
me into present position and whose boundless love, unparalleled affection, moral
support is a constant source of motivation for me in shaping up my career. Where
emotions are involved, words cease to express affection, encouragement and
cooperation of my lovable family friends Dr.Anurupa, Dr. Srilatha, Dr.
Phaneendra, Dr. Vijay, Dr.Chaithanyamani, Dr. Sahitya, Dr.Kusuma, Dr.
Sailaja, Dr. Viswaja, Dr. Priyanka Roberts , Dr. Shiny, Dr. Priyanka, Dr. Dileep,
Dr. Mahendra, Dr. Asha, Dr. Poori, Dr. Swapna, Dr.Watsyavi and Dr. Bharath
without which, I would have never come to this stage of career building.
I place on record my apologies and sincere thankfulness to the unmentioned
personalities, who have played a role in this study and preparation of the
manuscript.
Ramalakshmi….
xi
DECLARATION
I, Dr. N. RAMALAKSHMI (TVM/13-49), hereby declare that the
thesis entitled “SYNCHRONIZATION OF ESTRUS AND OVULATION
IN POSTPARTUM ACYCLIC CROSSBRED COWS” submitted to Sri
Venkateswara Veterinary University, Tirupati for the degree of MASTER
OF VETERINARY SCIENCE is the result of original research work done
by me. It is further declared that the thesis or any part thereof has not been
published earlier in any manner.
Date : (N.RAMALAKSHMI)
Place : Tirupati TVM/13-49
xii
Name of the author : N. RAMALAKSHMI
Title of the thesis : “SYNCHRONIZATION OF ESTRUS AND OVULATION IN POSTPARTUM ACYCLICCROSSBRED COWS”
Degree to which it is Submitted : MASTER OF VETERINERY SCIENCE
Faculty : Veterinary Science
Department : Veterinary Gynaecology and Obstetrics College of Veterinary Science, Tirupati.
Major Advisor : Dr. M.SRINIVAS Chairman of Advisory Committee Associate Professor Dept. of Vety. Gynaec. & Obstetrics NTR College of Veterinary Science Gannavaram 521101 [A.P.]
University : SRI VENKATESWARA VETERINARYUNIVERSITY, TIRUPATI.
Year of submission : November, 2015
ABSTRACT
The present Research work was undertaken by utilizing 24 postpartum
acyclic crossbred cows maintained under diverse (village) managemental
conditions. The work was designed to study the efficacy of different
synchronization protocols viz., Ovsynch (Group I), Ovsynch+PRID (Group
II) and PRID+PG (Group III) based on estrus response, duration of estrus,
intensity of estrus, serum progesterone concentration and conception rate.
The estrus response and duration of estrus after synchronization of
postpartum acyclic crossbred cows inGroup I, Group II and Group III was
xiii
75.00, 100.00 and 87.50 percent; 50.62±8.39hrs, 68.00±2.61hrs and
58.63±9.36 hrs,respectively.
Intensity of estrus exhibited was high of (62.5%) when synchronized
with Ovsynch+PRID protocol followed by PRID+PG (50.0%) andOvsynch
(25.0%) protocols. In Ovsynch (12.5% weak, 62.5% intermediate and 25%
intense) Ovsynch+PRID, (0% weak, 37.5% intermediate and 62.5% intense)
and PRID+PG, (12.5% weak, 37.5% intermediate and 50% intense).
The mean serum progesterone concentrations in Group I, Group II and
Group III on day ‘0’ were 2.56±1.04ng/ml, 1.66±0.24 ng/ml and 1.43±0.32
ng/ml,respectively and at the time of AI they were 7.60±0.87 ng/ml,
1.86±0.28 ng/ml and 2.50±0.65 ng/ml, respectively. The difference in the
serum progesterone concentrations amongst all the three synchronization
protocols was non-significant (P>0.05) recorded on day ‘0’ and day of AI.
The first service conception rate was 50% and 50% in crossbred
acyclic cows synchronized with Ovsynchand PRID+PG protocols,
respectively while it was comparatively lower in Ovsynch+PRID protocol
(37.50%). The overall conception rate in Ovsynch, Ovsynch+PRID and
PRID+PG protocols was 50%, 50% and 62.50%.
It was concluded from the present study that Ovsynch+PRID protocol
obtained better estrus exhibition, while PRID+PG was found to be effective in
getting optimum conception rate with fixed time artificial inseminationin
postpartum acyclic crossbred cows.
xiv
LIST OF SYMBOLS AND ABBREVIATIONS
AI : Artificial Insemination
PRID : Progesterone ReleasingIntravaginal Device
CL : Corpus Luteum
d : Days
FTAI : Fixed Time Artificial Insemination
GnRH : Gonadotropin Releasing Hormone
h/hrs : Hours
LH : Luteinizing Hormone
mm : Millimeter
ml : Millilitre
ng : Nano gram
µg : Micro gram
PGF2α : Prostagladin2α
SE : Standard error
TAI : Timed Artificial Insemination
Vs : Versus
% : Percent
< : Less than
> : Greater than
± : Plus or Minus
≥ : Greater than or equal to
1
CHAPTER-I
1.INTRODUCTION
Crossbreeding programme was introduced in India during late 1970’s
as 50 percent Bostaurus cross-bred cowsas these cows had 1.8 times higher
lifetime milk yields and a 1.2 times higher number of total lactations.
However, it had registered a negative correlation on reproductive traits
(Galukandeet al., 2013).
Assisted reproductive techniques like Estrus synchronization has been
promoted historically as a labor saving tool for those producers who want to
capitalize on the superior genetics available through use of AI. However, the
labor saving aspect is meagerwhen compared to the economic returns
available when estrus synchronization was used as a “reproductive
managemental tool”. Thus, estrous cycle was manipulated to bring large
number of females into estrus at a predetermined time to enhance the
reproductive efficiency by shortening the calving interval. This was done by
adopting reproductive management techniques like synchronization of
estrus/ovulationwith fixed timed artificial insemination yielding optimum
conception rates (Islam, 2011). Results of many of the synchronization
protocols depend on body condition scoreas it was the measure of nutritional
status of animals and was an important factor(Baruselliet al., 2011).
Ovsynchwas a fixed-time AI synchronization protocol that has been
developed, tested and used extensively in dairy cattle as it allows acceptable
synchrony of follicular development, regression of corpus luteum and
1
2
synchronizes ovulation allowing effective FTAIwith no need for heat
detection with optimum pregnancy rates (Stevensonet al., 2006). During
natural estrous cycle prostaglandin F2αreleased from the uterus was a
triggering factor that resulted in luteolysis and helped the diestrus open cowto
return to estrus every 21 days, this mechanism was used artificially to shorten
the life span of the CL by administration of PGF2α in several synchronization
protocols for induction of estrus in postpartum acyclic cows (Mel DeJarnette,
2004).
Administration of GnRH helped in termination of ovarian follicle
development of one wave and emergence of new follicle of next wave leading
to the maturing as dominant follicle within 7 days after the injection, thus
helping in synchronization of estrus/ovulation (Twagiramunguet al., 1995).
Use of exogenous progestagen like PRID along with Ovsynchprotocol
increasedthe pregnancy rates and decreased days open which was helpful to
bring the animals to fertile estrus (JagirSingh et al., 2009).
Perusal of literature revealed that limited studies were conducted to
evaluate the efficacy of different estrus synchronization protocols to
synchronize estrus and ovulation in postpartum acyclic crossbred cows under
rural conditions. Hence, the present study was undertaken to study the
efficacy of different estrus synchronization protocols.
3
CHAPTER-II
2. REVIEW OF LITERATURE
2.1 ESTRUS SYNCHRONIZATION
Whittier et al. (1989) expressed that prostaglandins and its analogues
were approved and being used to improve the reproductive efficiency in dairy
herds as it increased the conception rates by effective observation of cyclicity
and detection of estrus.
GnRH along with progesterone and PGF2α resulted in an acute
treatment for programmed follicular development and ovulation (Thacther et
al., 1993). Interval of 6 or 7 days between Buserelin and PGF2α had
satisfactory synchronization with regards to fertility (Coleman et al., 1991 and
Guilbault et al., 1991) when compared with two PGF2α injections at 11 days
apart (Coleman et al., 1991). Gonadotrophin releasing hormone (GnRH)
occupies a central role in the reproductive function and has a potential for
fertility control in mammals (Diskin et al., 2002).
Estrus detection is one of the most important factors affecting the
reproductive success of artificial insemination programs, an increase in basic
understanding to manipulate ovarian follicular and corpus luteum dynamics
over the last decade have developed better results in synchronization protocols
and these protocols have a potential to enhance pregnancy rates and successful
artificial insemination programs (Rajamahendran et al., 2001).
Use of various hormonal combinations like estrogen and GnRH and
steroids like estradiol, progesterone with PGF2α were used for the regulation
3
4
of lifespan of the corpus luteum, controlling follicular wave emergence and
ovulation (Larson and Ball, 1992 and Thatcher, 2001).
Progesterone therapy was the treatment of choice for inducing cyclicity
in postpartum anoestrus cows, where hormones progesterone and
GnRH+PGF2α were used for the onset of estrus as in most of the anoestrus
cows there was no progesterone in the animal’s circulation upto 45 days of
calving due to which there was failure of ovulation and CL formation
(Mozaffari et al., 2014). Progestagens yielded satisfactory results in crossbred
cows under tropical conditions for induction of estrus and ovulation (Soto et
al., 1998 and 2002).
Progesterone releasing inserts have been used to synchronize estrus where
85% of the cattle exhibited estrus between 36 and 60 hrs after removal of the
device (Cavalieri et al., 2004).
Widespread acceptance of follicular wave emergence and luteal
regression using GnRH and PGF2α was seen in ovsynch protocol for dairy
herd management, while a second dose of GnRH after 48 h of administering
PGF2α induced ovulation and allowed fixed time insemination after 16 h
(Kasimanickam et al., 2004).
The ability to precisely control the time of ovulation after a
programmed follicular development and corpus luteum regression
sequentially permits a timed insemination which synchronizes with estrus and
helps in overcoming the errors in heat detection (Ozturk, 2009).
5
Synchronization of estrus could be accomplished with the injection of
prostaglandin alone, but this needed correct identification of the ovarian status
of cows as prostaglandin is sensitive to functional corpus luteum aged
between 8 to 17 days of the estrus cycle. Progesterone therapy may reduce
fertility upto 14%, but short time progesterone exposure (≤14 days) was
beneficial. GnRH addition in progesterone and prostaglandin synchronization
programme was more helpful to induce estrus as this protocol synchronized
estrus in delayed pubertal heifers and postpartum cows. Newer methods of
synchronizing estrus with GPG protocol preceded by progesterone treatment
were effective with high fertility (Islam, 2011).
Synchronization of estrus shortened the calving interval, increased
uniform calving dates, reduced the time devoted for estrus detection and
facilitated the use of AI (Waldmann et al., 2006) and thereby enhancing the
economic returns to farmers (Islam, 2011).
Estrus synchronization, ovulation synchronization and AI are
reproductive management tools that have been available to farmers for more
than 30 years. These tools remain the most important and widely applicable
reproductive biotechnologies available for beef cattle operations (Seidel,
1995). Ideal synchronization program should have similar or more conception
rate than the natural conception rate and the selection of the protocol should
be on the basis of its managemental capabilities and expectations of the farmer
(Vasconcelos et al., 1999).Synchronization of estrus is one of the advanced
6
managemental process through which the humane errors and managemental
costs could be minimized (Islam, 2011).
2.1.1 Ovsynch Protocol
Wolfenson et al.(1994) reported that use of Buserelin (8µg) on day 12
and seven days prior to synchronization of estrus with PGF2α altered follicular
development and produced preovulatory follicles which were more
homogenous, more estrogen-active and more dominant with a greater size
difference between the preovulatory and subordinate follicles prior to estrus
when compared to untreated cows.
A protocol using GnRH and PGF2α called Ovsynch was developed to
synchronize ovulation in dairy cattle (Pursley et al., 1995; Pursley et al., 1998
and Moreira et al., 2000a) and with a goal of synchronizing the ovulation
within 8 h period (from 24 to 32 h after the second GnRH treatment) enabling
TAI without the detection of estrus (Pursley et al., 1995) and with pregnancy
rates in the range of 30 to 40 % (Burke et al.,1996; Pursley et al., 1997a and
Stevenson et al., 1999). In Ovsynch protocol, GnRH injection was
administered on day 0followed by PGF2 after 7 days and a second injection
of GnRH after 48h with TAI at 72 h after PGF2.Synchronization with
Ovsynchprotocol was successful to detect estrus, efficient artificial
insemination and also helped the producers to enhance reproductive
efficiently as this protocol caused precised ovulations (Pursley et al., 1995).
The series of injections, synchronized ovulation for timed AI with
uncompromised pregnancy rates (Pursley et al., 1997) and this administration
7
of GnRH 6 days prior to PGF2 treatment improved the precision of estrus as
reported by Pursley et al., (1995). Thus, Ovsynch is an effective planned
breeding program developed for lactating dairy cows which allowed TAI
without estrus detection (Burke et al., 1996; Pursley et al., 1997a, 1996 and
1995 and Schmitt et al., 1996).
Geary et al., (1998) reported that Ovsynch protocol was capable of
inducing fertile ovulation in anoestrusand cycling beef cows. In addition,
Rabiee et al. (2005) and Kacar et al. (2008)also have recommended that
Ovsynch with TAI as one of the advanced reproductive tool for
improvementof reproduction in lactating dairy cows.
Ovarian follicles in cattle grow in distinct wave-like patterns with
generally one follicle becoming dominant (Fortune et al., 1988). Estrogens
and GnRH induce atresia or ovulation of dominant follicles and synchronize
the emergence of a new follicular wave (Macmillan and Thatcher, 1991; Bo et
al., 1994; Wolfenson et al., 1994 and Burke et al., 1999).
Controlling follicular waves with a single injection of GnRH at random
stages of the estrous cycle induces release of LH leading to ovulation or
luteinization of the dominant follicle(s) (≥10 mm) (Garverick et al., 1980; Bao
and Garverick, 1998 and Sartori et al., 2001). GnRH has synchronously
terminated most stages of ovarian follicle development to be followed by a
synchronized emergence of a new follicular wave leading to the presence of a
maturing dominant follicle 7 days after the injection (Twagiramungu et al.,
1992 and 1995). Further studies of Silcox et al.(1995) revealed that first
8
GnRH injection in Ovsynch induced a new follicular wave with a dominant
follicle that ovulated in response to the second GnRH injection given on
day 9.
Luteal tissue that formed after the GnRH administration was capable of
undergoing PGF2induced luteolysis 6 or 7 days later (Twagiramungu et al.,
1995). Follicular waves are controlled with an injection of GnRH followed 7 d
later by an injection of PGF2 to lyse the CL. After PGF2 a second injection
of GnRH was administered 48 h later to initiate ovulation of a dominant
follicle followed by TAI after 16 h (Lamb et al., 2010).
Vasconcelos et al. (1999) and Navanukraw et al. (2004) reported that
the ability of GnRH-PGF2based protocols to precisely synchronize estrus
and / or ovulation was dependent upon the stage of the follicle at the time of
the initial GnRH injection and is the major limitation in synchronization
programs.
Bello et al. (2006) observed that the ovulatory response after the first
GnRH administration was a critical factor for successful synchronization of
ovulation in Ovsynch protocol and also stated that high ovulation rate after the
first GnRH treatment increased the likelihood that cows will have a functional
dominant follicle capable of ovulation during the final GnRH treatment.
Previous studies have shown that response to first GnRH in Ovsynch protocol
was 45-90% and the synchronization rate was 90.1% (Pursley et al., 1995;
Vasconceles et al., 1999; Bello et al., 2006; Galvao and Santos 2010 and
Keskin et al., 2010). Atkins et al. (2008) had linked the size of the dominant
9
follicle at the time of the second GnRH with the ability of the first GnRH to
reset follicular development at appropriate stage of the estrous cycle.
Thatcher et al. (1993) reported that GnRH-induced turnover of follicles
or induction of a new follicular wave will be most efficient if ovulation was
induced in response to the first administration of GnRH and resetting
follicular development which could produce a new dominant follicle
containing an oocyte of greater fertility (Mihm et al., 1994). The cows
ovulating after the first GnRH treatment in Ovsynch have higher rates of
pregnancy than those of non responders (Bello et al., 2006 and Cirit et al.,
2007).
Perry et al. (2005) reported that follicles of smaller than normal
diameter ovulated and resulted in decreased fertility and correlated that these
females might have had decreased preovulatory concentrations of
estradiol.Lamb et al. (2010) also recorded similar findings when the interval
between GnRH and PGF2 administration was 7 days.
Vasconcelos et al. (1999) reported that the overall synchronization rate
in Ovsynch protocol was 85% and there were clear differences in response
according to the day of protocol initiation. They have also recorded that 64%
of cows ovulated to the first GnRH and 93% of the cows showed low
progesterone at second GnRH after PGF2 administration.
The stage of the estrous cycle when Ovsynch was initiated also
affected synchronization and conception rate. Initiation of Ovsynch protocol
in cows during the early cycle had higher synchronization rates but lower
10
pregnancy rates per AI possibly due to presence of large follicles than in cows
during the mid cycle which had the smallest ovulatory follicle and the greatest
pregnancy rate per AI(Vasconcelos et al., 1999 and Aali et al., 2008).
Moreira et al. (2000a) reported that initiating the Ovsynch protocol in
dairy heifers on days 15 of the estrous cycle exhibited estrus before the second
GnRH injection whereas no estrus behavior was observed when the protocol
was initiated on d 2, 5, 10 (or) 18 of the estrous cycle.
Pursley et al. (1995) recorded that ovulations occurred 24-32 h after the
second GnRH treatment in cattle. In subsequent studies,Pursley et al. (1998)
reported that conception rate was reduced, if AI was performed at 32 h after
the second GnRH treatment in the Ovsynch protocol or just after ovulation
compared with AI done at 8-24 h after detected estrus in dairy cows.
Momicilovic etal.(1998) observed that better reproductive performance was
observed in cows inseminated at synchronized ovulation rather than in cows
inseminated at synchronized estrus period.Geary et al. (2001) reported greater
conception rates with Ovsynch in cyclical cows when compared to anoestrus
cows. In another study Peters and Pursley (2003) reported that administration
of second GnRH in Ovsynch protocol at 0 h or within 24 h after PGF2
resulted in poor fertility compared to its injection at 36 or 48 h after PGF2.
Dejarnette (2004) reported that though Ovsynch allowed acceptable
pregnancy rates with no heat detection, it does not eliminate the need for heat
detection and also opined that natural heats can occur on any given day and as
many as 20% of cows will display standing estrus between days 6 and 9 of the
11
Ovsynch protocol and conception rates in these animals will be compromised
if bred strictly on a timed AI basis.The disadvantage of this protocol is that
approximately 5 to 15% of lactating cows exhibit estrus before or immediately
after the PGF2 injection (Kojima et al., 2000 and Lamb et al., 2001). These
cows might have been in the late stages of the estrous cycle when the
synchronization protocol was initiated (Geary et al., 2000).
Moreira et al. (2000b) observed incomplete luteal regression rate (21.0
%) 48 h after injection of PGF2which resulted in decreased pregnancy after
TAI (Burke et al., 1996, Peters et al., 1999 and Moreira et al., 2000).Kim et
al. (2003) also reported that 12.9% of the cows exhibited premature estrus
prior to injection of PGF2 in Ovsynch protocol andbased on serum
progesterone concentrations (48 h after the injection of PGF2)approximately
25.8 % of the cows in Ovsynch group had incomplete luteal regression.
2.1.2 Ovsynch with PRID protocol
The basic Ovsynch protocol, with numerous variations have been
tested and developed where they have become standard components in current
breeding management has TAI to avoid practical difficulties associated with
detection of estrus.
Failure of response to the initial GnRH injection in the Ovsynch
protocol has resulted in lowered TAI pregnancy rates due to asynchronous
ovarian responses (Vasconcelos et al., 1999; Dejarnette et al., 2001 and Bello
et al., 2006) and inability of the GnRH to turn over dominant follicles late in
the estrous cycle leading to premature estrus in 8-10 % of treated cows (Geary
12
et al., 2000), 5–15% of treated cows ( Roy and Twagiramungu 1996 and1999;
Seguin, 1997 and Dejarnette et al., 2001) and in 11-14% of treated cows
(Gabor et al., 2002). In Ovsynch protocol after the injection of PGF2on the
day 7 at times resulted inpremature estrus, incomplete luteal regression
associated with conception failure (Burke et al., 1996).
Similarly, Moreira et al. (2000a) demonstrated that the CL formed by
the first injection of GnRH had not regressed completely after the PGF2
injection. Therefore modifications have been employed to improve the
Ovsynch protocol (Lamb et al., 2001 and Martinez et al., 2000).
Alternatively, inclusion of an exogenous progesterone device such as
CIDR/PRID inserts between GnRH and PGF2 injection prevented
premature estrus with increased response to estrus synchronization in cyclical
as well as anoestrus cows (Kojima et al., 2000) with enhanced the pregnancy
rate (Martinez et al., 2002 and Steckler et al., 2002).Accordingly, Thatcher et
al. (1989) observed that buserelin administration at the time of CIDR insertion
causedovulation or partial luteinization of follicles and 3 to 4 days later a new
wave of follicles were recruited.Ryan et al. (1995) reported that intravaginal
insertion of a progestagen for 8 d, with buserelin treatment on the day of
progestagen insertion and PGF2 treatment on the day before progestagen
removal resulted in the best overall estrus detection rate and pregnancy
rate.Intravaginal progesterone insert (CIDR) during an Ovsynch protocol
enhanced the fertility rate in noncycling cows (Pursley et al., 2001).
13
Kim et al. (2003) have also tried insertion of CIDR progesterone
device combined with a capsule containing 10 mg estradiol benzoate as an
alternative to administration of the first GnRH treatment in the Ovsynch
protocol and stated that progesterone based TAI protocol would prevent
premature estrus and incomplete luteal regression with increased pregnancy
rate.
Savio et al. (1993) and Diskin et al. (2002) have stated that the size and
maturity of the follicle at the time of PGF2 treatment was an influencing
factor in synchrony of estrus and ovulation.Utt et al. (2003) concluded that
removal of CIDR after 9 days resulted in a larger dominant follicle compared
to removal after 7 days.
In the studies of Lane et al. (2001); Utt et al. (2003);Cavalieri et al.
(2004) and Hittinger et al. (2004) the diameter of the ovulatory follicle,
synchrony of the estrus, synchrony of ovulation and diameter of the corpus
luteum post ovulation were not influenced by the duration of the
progesterone-releasing insert (5, 7, 8, or 9 days).
Kawate et al.(2004) conducted experiments in suckled Japanese Black
cows were in control group were given GnRH (100µg) on day zero, PGF2α
(500µg) on day 7, GnRH on day 9 with AI on day 10 and cows of treatment
group were given CIDR for 7 days along with standard Ovsynch protocol.
Plasma progesterone concentrations were determined on day 0, 1, 7, 9, 10 and
17. The conception rate was greater in Ovsynch+CIDR group (72.5%) when
compared to Ovsynch group (47.7%).
14
Kim et al. (2005) reported that the treatment with GnRH in a CIDR
based FTAI protocol has induced synchronized follicular wave emergence
with a large preovulatory follicle and synchronous ovulation following a
second injection of GnRH with acceptable pregnancy rate in lactating Holstein
cows.
Amongst Ovsynch and Ovsynch+CIDR protocols,Ovsynch+CIDR
protocol had more conception rate of 67.7% when compared to Ovsynch
alone. Inclusion of CIDR in Ovsynch protocol prevented early maturation of
follicles by maintaining elevated blood progesterone concentrations until
PGF2α was administered (Sakase et al., 2005).
Kim et al. (2005) evaluated the efficacy of three protocols using
CIDR+P+G, G+CIDR+P+G and EB+CIDR+P+G for estrus synchronization
in lactating Holstein cows. They concluded that G+CIDR+P+G protocol
resulted in synchronous follicular wave emergence, large preovulatory
follicles and synchronous ovulation with higher pregnancy rates to TAI.
Stevenson et al.(2006) conducted studies with CIDR insert during the
Ovsynch protocol and recorded increased fertility in lactating cows having
low serum progesterone before PGF2α injection and concluded
thatprogesterone supplementation during an Ovsynch protocol would enhance
fertility in lactating dairy cows. They further opined that supplementation of
progesterone, pretreatment cycling status, and luteal status before PGF2α
injection altered the follicular diameters at the time of the second GnRH
injection, but were unrelated to pregnancy outcomes.
15
Sakase et al. (2007) demonstrated that Ovsynch+CIDR protocol
corrected premature follicular maturation and ovulation and precised the
timing of TAI in the beef cows by maintaining high blood progesterone level
until administration of PGF2.
Ambrose et al. (2008) observed that pregnancy rates (61.8%) were
higher in Holstein heifers, irrespective of season when Ovsynch protocol was
adopted in combination insertion of intravaginal progesterone releasing device
(CIDR) when compared to that of Ovsynch alone.CIDR (Progesterone
releasing device) and PGF2α program increased the occurrence of estrus,
pregnancy rates and overall conception rates were significantly high in
anoestrus non-descriptive cows than unsynchronized cattle (Vijayarajan and
Meenakshisundaram, 2013).
2.1.3 PRID with PG protocol
The retention rate of PRID was 100% and more than 80% of the
animals exhibited signs of estrus after removal of PRID in post-partum cows.
Maximum progesterone concentrations were attained within 24h of PRID
insertion which was 2.5 ng /ml and gradually decreased to 1ng/ml by day 12
the day of device removal. Conception rates to natural mating were 26% while
the same for fixed-time insemination at 60 and 84 h after PRID removal was
33% and it was concluded that use of intra vaginal progesterone device
without any hormonal supplementation yielded very low conception rates
(Rajamahendran et al., 1983).
16
In the absence of a corpus luteum, intravaginal progesterone (CIDR)
inserts consisting of a layer of silicone containing 10% progesterone by
weight (1.38g) molded over a T-shaped nylon spine acted as an artificial CL
by releasing sufficient progesterone to maintain plasma progesterone
concentrations >2 ng/ml for at least 7 d (Brown et al., 1988; Macmillan et al.,
1991; Van Cleeff et al., 1992 and Lucy et al., 2001) and an injection of
PGF2 the day before CIDR removal caused synchronization and improved
pregnancy rates (Lucy et al., 2001).While, Kyle et al. (1992) reported that
exposure to progesterone was a prerequisite to first postpartum behavioral
estrus in a large portion of cows. Anderson et al. (1996), Fike et al. (1997)
and Imwalleet al. (1998) also reported that progesterone in the
synchronization of estrus treatment regimen initiates estrous cycles in a
portion of anoestrus cows and peripubertal heifers andreduced the interval to
pregnancy.
McDougall et al.(1992) reported that progesterone pretreatment in
postpartum cows sensitized the receptors in the brain, which were then able to
respond to ovarian estrogen by eliciting the psychic phenomenon associated
with estrus.
Roche et al. (1999) reported that administration of the progestagen for
7 days before PGF2ensures that CL would regress in response to
PGF2becauseall cattle would have a CL aged about 7 days. They have also
stated that the progestagen will also delay the estrus incattle that naturally
undergo CL regression during the progestagen treatment period before
17
PGF2injection.The rationale for inclusion of the progesterone during the
period between GnRH and prostaglandin was that progesterone prevented
premature ovulation after spontaneous luteolysis during the treatment period
and a small proportion of cows whose dominant follicles failed to respond to
GnRH (Xu and Burton, 2000 and Xu et al., 2000).
Lane et al. (2000) conducted a study by decreasing the length of
treatment with PRID inserted for 7 days and injected PGF2α one day before
the device removal and observed that progesterone treatment improved the
estrus synchrony. They opined that pregnancy rates were high when short-
term progestagens were used along with a luteolytic agent when compared to
use of long-term progestagens. While, Stevenson et al. (2000) stated that
limitation of synchronization programs was the presence of either anoestrus
cows or prepubertal heifers in a breeding herd and about 60% of beef cows
may not be cycling at the initiation of a breeding season. On the other hand,
Lucy et al. (2001) have observed that administration of the CIDR for 7 days
with an injection of PGF2 on day 6 of insertion was an effective method for
estrus synchronization in cattle.
Progestagen administration accomplished two objectives: 1) it
suppressed estrus in cows and heifers that have spontaneously regressing CL
during the administration period and upon progesterone withdrawal these
cows and heifers expressed a synchronized estrus and 2) the CL in cows and
heifers that was within 1-5 d of the estrous cycle at initiation of progesterone
administration, continued to develop during the progesterone administration
18
period, so that it responded to PGF2 at the time of its administration. Thus,
all cows and heifers that are estrus/cycling are expected to have a
synchronized estrus in response to a program incorporating administration of
progesterone for 7 d with an injection of PGF2 near the end of progesterone
administration (Chenault et al., 2003).
The increased proportions of anoestrus suckled beef cows that ovulated
and formed a CL of normal lifespan after CIDR removal were 44% ( Fike et
al., 1997) and 41% for multiparous cows and 75% for primiparous cows
(Wheaton and Lamb, 2007).
Alnimer and Lubbadeh (2003) recorded an increased pregnancy rates
by adopting PRID in combination with Ovsynch protocol (65%) with TAI
compared to that of Ovsynch alone (30%) with AI at detected estrus. This
justifies the use of PRID along with Ovsynch to induce estrus, increase
pregnancy rates and decrease days open.
Chenault et al. (2003) reported that initiation of estrous cycles after
administration of CIDR inserts could have a major impact on the fertility as
measured by first service conception rate or first-service pregnancy rate at the
estrus following insert removal. Further, they have reported that retention
rates of CIDR inserts ranged from 90 to 96%, if loss rates were>5% the
producers should evaluate their insertion technique, housing and animal
density and should consider clipping the tails of the inserts after insertion into
the vagina. Since loss of a CIDR insert does not necessarily result in lack of a
synchronized estrus, those cows and heifers that have lost their inserts might
19
have a spontaneously regressed CL during the CIDR administration period
which might lead to occurrence of a pre-mature estrus instead of a
synchronized estrus during the first 3 to 4 d after the scheduled day for insert
removal.
Walsh et al. (2007) determined the occurrence and intensity of
vaginitis based on the amount of debris on the intra vaginal progesterone
device at removal. They recorded that 28% of the cows had evidence of mild
vaginitis in response to the intra vaginal device, whereas 6% of the cows had
copious debris associated with device at removal. They further reported that
the pregnancy rates were 43.8% after fixed artificial insemination when
treated with PRID and the same were 34.9% when treated with placebo intra
vaginal device. PRID has the efficacy to induce estrus in anoestrus cows and
decrease total days open. They concluded that vaginitis score did not show
any effect on the reproductive outcome.
Earlier reports cited that fertility depends on the lifespan of ovulatory
follicle and concluded that ovulatory estrus could be successfully induced by
using PRID for 15 days and bred at 48-72 h after its removal. It was observed
that short life spanned ovulatory follicle had better post-ovulation luteal
profile than long life spanned ovulatory follicles in true anoestrus buffalo
heifers (Jagir Singh et al., 2009).
Pacala et al. (2010) evaluated two protocols of Ovsynch+PRID (1.55g)
with that of Ovsynch alone where PRID was removed on day 8 and eCG was
given instead of GnRH as in Ovsynch. They opined that progestagen
20
treatments mimed the luteal phase of estrous cycle and thus recommended
their use for heat induction as they stimulated the hypothalamus-pituitary-
ovarian axis, while eCG at the end of progestagenic treatment stimulated the
terminal folliculogenesis and ovulation.
Ovarian inactivity during anoestrus was related to low level of pituitary
and gonadotrophic hormones, thus progesterone treatment in these animals
was effective for induction of estrus and also explains that
Progesterone+GnRH treatment was further more effective. Progesterone acted
as an artificial CL, while its withdrawal removedthe negative feedback on
hypothalamus and promoted estrus with follicular development (Pawar et al.,
2012).
From the later studies it was noticed that PRID-Delta (1.55g)
maintained greater circulating progesterone levels when compared to CIDR
(1.38g) where animals had come to estrus within 4 days of insertion with
potential benefits in fertility of dairy cows. The protocol included insertion of
PRID/CIDR on day 0, PGF2α (25mg) on day 6, PRID/CIDR removed on day
7 and the animals were inseminated 56 h after removal. Final cumulative
pregnancies per AI were greater in PRID-Delta group (Van Werven et al.,
2013).
Progesterone therapy along with other hormones was effective for
treatment of anoestrus cows, for better response an intravaginal progesterone
device was used along with other hormones which resulted in estrus induction
rates ranging from 80% to 100%. GnRH along with intravaginal device like
21
PRID induces ovulation if a mature follicle was present at the time of
inducing LH surge, while a single injection of GnRH was not effective in deep
anoestrus cases. For better results GnRH has been combined with drugs such
as phosphorous, estradiol and progesterone (Shams et al., 1991 and Rhodes et
al., 2003). It was further opined that PGF2α was effective between 6-16th day
of the cycle in the presence of active CL (Kumar et al., 2014).
Mozaffari et al. (2014) concluded that progesterone therapy was the
treatment of choice for inducing cyclicity in postpartum anoestrus cows with
low body condition score (<3 in1-5 score).
2.2 ESTRUS INDUCTION EFFICIENCY
2.2.1 Estrus Response
Ryan et al. (1995) reported that estrus detection rate in CIDR+PG
protocol was 85 % (8 days CIDR with PG one day before), but Chenault et al.
(2003) reported that the estrus was 58 % in cows on d 1, 2, and 3 after insert
removal following the CIDR+PG treatment.
Steckler et al. (1999) reported that estrus response was 94% with both
Ovsynch and Ovsynch +CIDR protocols.
Lucy et al. (2001) recorded that 59% of cows were in estrus within 3 d
across all locations in both cyclic and acyclic statuses in CIDR+PG protocol,
respectively.
Estrus was synchronized in only 48% of the cows treated on d 3 and in
100% of the cows when treatment began on d 9 of the estrous cycle with
progesterone treatment (Pratt et al., 1991).
22
Stevenson et al. (2004) stated that the proportion of cows that were
detected in estrus after 2nd GnRH in Ovsynch were 54% and addition of
CIDR insert had no effect on the incidence of estrus. But, Xu and Burton,
(2000) reported that estrus response was 92.2% when cows were treated with
GnRH agonist and CIDR followed by PGF2 injection on day 7 and device
removed on day 8 and 92.8% when device was removed on same day in a
total of 6 days.
Murugavel et al. (2010) observed that estrus induction in anoestrus
cows after CIDR+PG protocol was 81.82% with 63.64% ovulation rate
following induction of estrus.Cevik et al. (2010) reported that estrus response
in lactating dairy cows treated with Ovsynch and CIDR+PG protocol were
46.2 and 66.7%, respectively.
2.2.2 Duration of estrus
Sathiamoorthy et al. (2007) reported that estrus duration was 18.4±2.6
h in post partum nondescript cows in Ovsynch protocol and the same was
16.2±4.2 h in buffaloes.
Jyothi (2011)reported that the mean duration of estrus in postpartum
crossbred cows with Ovsynch,Ovsynch+CIDRand CIDR+PG protocols was
24.17±0.75 (range from 21 to 28), 23.33±1.18 h (range from 17 to 30) and
25.50±0.70 (range from 24 to 30), respectively and concluded that the
duration of estrus in CIDR+PG protocol was longest when compared with
other protocols.
23
2.2.3 Intensity of estrus
Callesen et al. (1986, 1987 and 1993) reported that animals that
belonged to weak estrus intensity group were expected to have poor oocyte
and/or follicular quality with reduced capacity for fertilization and embryonic
development.
Ravikumar et al. (2009) observed that the percent of animals showing
intense estrus was almost the similar in Ovsynch and Ovsynch+CIDR
treatments in subestrus buffaloes.
In CIDR+PG protocol the percent of anestrous cows exhibiting intense
estrus behavior were 63.64 and the percent of moderate and weak estrus
intensity was 18.18 and 18.18, respectively (Murugavel et al., 2010).
Jyothi (2011)observed that thepostpartum crossbred cows treated with
Ovsynch,Ovsynch+CIDRand CIDR+PG protocols exhibited intense estrus in
33.33 (4/12), 58.33 (7/12) and 66.67 (8/12) percent of cows and intermediate
estrus in 33.33 (4/12), 16.67 (2/12) and 33.33 (4/12) percent of cows,
respectively. Weak estrus was recorded in Ovsynch (33.33) (4/12)
andOvsynch+CIDR (25.00) (3/12) protocols.
2.3 SERUM PROGESTERONE ASSAY
Fonseca et al. (1983) showed a positive relationship between
concentration of progesterone at induction of luteolysis and conception rates.
Schmitt et al. (1996) indicated that the mean progesterone values were
in increasing trend from the day of treatment which might be due to the
formation of accessory CL by GnRH administration.
24
Pursley et al. (1997a) reported that evaluation of serum progesterone
concentration at each hormonal injection indicated that the first injection of
GnRH synchronized luteal function of lactating dairy cows but not of heifers
and CL regression occurred in 94% of cows in Ovsynch group (high
progesterone on the day of PGF2 injection and low progesterone 24 to 48 h
later). On the day of first GnRH injection, where 61.2% cows showed high
concentration of progesterone and this percentage has increased to 86% on the
day of PGF2 injection but the pregnancy rate was unaffected by the
concentration of progesterone.
Vasconcelos et al. (1999) observed that the stage of estrous cycle
affected serum progesterone concentration at first GnRH and at PGF2
treatment but not at second GnRH. Further, cows in the later estrous cycle
(days 10-12) were more likely to have low serum progesterone (<1ng/ml) at
PGF2 than those early in the cycle. Overall 20% of cows had a low
progesterone concentration before the injection of PGF2 and 93% had low
progesterone by the time of second GnRH. They have also showed that cows
having low progesterone concentrations at the time of the administration of
PGF2 in the Ovsynch protocol had significantly lower conception rate when
compared to that of those cows having high progesterone concentration.
Kawate et al. (2004) observed that plasma progesterone concentrations
were not significantly different between days 0 and 1 and significantly
increased from days 1 to 7 in Ovsynch group but the same progesterone
25
concentration were increased significantly from days 0 to 1 and did not
change significantly from days 1 to 7 in the Ovsynch+CIDR group.
Sakase et al. (2005) observed significantly higher plasma progesterone
concentrations in Ovsynch+CIDR than in Ovsynch protocol on day 7. Plasma
progesterone concentrations on day 1 were greater in the Ovsynch+CIDR
group than in the Ovsynch group and tended to be higher in the
Ovsynch+CIDR group than in the Ovsynch group on day 7 but were not
significantly different between the groups on days 9, 10, or 17 (Kawate et al.,
2004). Further, It has been suggested by Folman et al. (1990) that higher
blood progesterone concentrations during the luteal phase preceding the
insemination increased conception rates in dairy cows. It was also mentioned
that plasma progesterone concentrations in CIDRtreated cows remained
elevated for 7 days (to the time of CIDR removal), perhaps these elevated
progesterone concentrations increased the conception rate (Kawate et al.,
2004).
Stevenson et al. (2006) stated that cows having low progesterone at
PGF2 injection benefited from progesterone supplementation regardless of
pretreatment cyclic status (conception rate in Ovsynch+CIDR 36% vs
Ovsynch18%). They have also observed that the progesterone concentration in
blood samples collected just before the insert removal was 2.2±0.3 and
2.4±0.3 ng/ ml in Ovsynch and Ovsynch+CIDR, respectively. Progesterone
concentration in blood samples one hour after insert removal and before
PGF2 injection was 2.4±0.2 and 2.5±0.2 ng/ml in Ovsynch+CIDR and
26
Ovsynch groups, respectively. The serum progesterone concentration
approached basal levels in 83 to 99% cows in Ovsynch+CIDR and 79 to
100% in Ovsynch cows.
Sakase et al. (2007) reported that the plasma progesterone
concentrations decreased below 0.5ng/ml on day 5 in Ovsynch group whereas
this occurred on day 8 in Ovsynch+CIDR treated group. They have concluded
that the dominant follicle ovulated on day 10 in the Ovsynch group while it
ovulated on day 11 in Ovsynch+CIDRtreated group.
Sathiamoorthy et al. (2007) reported that the progesterone
concentrations on day 0, 6 and 9 were 3.84±0.57, 4.98±0.63 and 0.65±0.12
ng/ml, respectively in cows treated with Ovsynch protocol.
Jyothi (2011)recorded that the mean serum progesterone concentrations
on the day of treatment initiation i.e. on day 0 were 1.16±0.28 (range from
0.38 to 2.31), 1.98±0.34 (range from 0.07 to 3.08) and 2.29±0.26 (range from
1.28 to 3.28) ng/ml in Ovsynch,Ovsynch+CIDR and CIDR+PG groups,
respectively. It was also observed that the mean serum progesterone
concentration on the day of AI were lowest in Ovsynch protocol (0.95±0.05
ng/ml) (range from 0.77 to 1.17) when compared withOvsynch+CIDR
(0.96±0.17 ng/ml) (range from 0.04 to 1.46), CIDR+PG (1.00±0.16 ng/ml)
(range from 0.62 to 1.69) protocols.
27
2.4 EFFECT OF ESTRUS SYNCHRONIZATION PROTOCOLS ON
CONCEPTION RATE
2.4.1 Breeding at FTAI
Artificial inseminations impart new genetic material from progeny
tested bulls but it requires accurate estrus detection (Taponen, 2009). Lack of
an efficient and accurate method of estrus detection at field level was the
major limiting factor in the reproductive performance of lactating dairy cattle
(Mayne et al., 2002). The estrus periods in nearly half of the normal cycling
dairy cows in a herd could not be detected as reported by Rounsaville et al.
(1979) and Pankowski et al. (1995).
Larson and Ball, (1992) reported that pregnancy rates from fixed TAI
following synchronization with PGF2 were inconsistent particularly in
lactating cows as compared to heifers mainly due to changes in the time of
ovulation in relation to AI which resulted in variable estrous cycle length in
cows (Smith et al., 1998).
Pursley et al. (1995 and 1997) have developed TAI program with
Ovsynch that reduced the emphasis on detection of estrus because all cows
were inseminated at a specified time relative to hormonal injection.
Thatcher et al. (1993) reported that fixed time insemination program
could potentially revolutionize reproductive management in dairy animals
which eliminated the need of estrus detection.
28
Burke et al. (1996) and Stevenson et al. (1999) observed that the
pregnancy rates in cows receiving AI at observed estrus after GnRH–PGF2
were higher when compared to Ovsynch with FTAI program.
Chenault et al. (2003) concluded that estrus after CIDR insert removal
was distributed over a 3 to 4d interval making it unacceptable for fixed TAI.
Lamb et al. (2010) reported that TAI protocols reduced the annoying
factors associated with ovulation synchronization and AI on detected estrus
and opined that they could provide an fixed time insemination program
efficient and effective means for capturing selective genetic traits of economic
consequences. They have also stated that differences in the pasture and diet,
breed composition, body condition, postpartum interval, climate, and
geographic location would affect the success of TAI protocols. All these
hurdles have motivated the scientists to evolvenumerous estrous
synchronization protocols having TAI that suited the area specific
requirements (Borman et al., 2003 and Amer, 2008).
2.4.2 Conception Rate
The first service pregnancy rate was a valuable tool for evaluation of
fertility which at 60-70% was stated to be optimum in well managed herds
(Yildiz, 2010). Geary et al. (2001) reported that conception rates of TAI were
higher for cycling cows than for non-cycling cows. Burfening et al. (1978)
stated that breeding the heifers at 80 h after the second injection of PGF2
might be too late thus leading to reduced conception rates.
29
Hansel et al. (1961) and Zimbelman et al. (1970) reported that fertility
was considerably reduced by use of long term progestagens treatment (10 to
20 d) while short-term progestagen treatments (< 10 d) used in conjunction
with PGF2 did not reduce the pregnancy rates (Roche, 1976 and Heersche et
al., 1979).
However, Beal et al. (1988) reported that short term progestagen
treatment in cattle which was initiated later than 13d of the estrous cycle also
exhibited reduced fertility. This reduction in the fertility rate might be
associated with the ovulation of persistent follicles (Rajamahendran and
Taylor, 1991 and Schmitt et al., 1994) which might be overcome by
administering GnRH for recruitment of a new follicular wave (Macmillan and
Thatcher, 1991 and Twagiramungu et al., 1992).
Elsewhere it was reported that conception rates were 26% in natural
mating and the same at fixed time artificial insemination was 33% which was
higher than natural mating (Rajamahendran, 1991).
In CIDR+PG protocol (8 days CIDR with PG one day before) the
pregnancy rate to first AI was 46.6% (Ryan et al., 1995).In CIDR based
synchronization studies, Day and Macmillan (1996) and Kastelic et al. (2001)
proved that conception rates to fixed TAI were not different when PGF2 was
administered on Days 6 or 7 of a 7 day CIDR treatment regime. While, Xu et
al. (1996) and Ryan et al. (1995) reported a reduced conception rate to AI in
lactating dairy cows following 8d CIDR insert administration with
administration of PGF2 either 1 day or 2 day before insert removal.
30
Lucy et al. (2001) observed that beef cows and heifers were in estrus
within the first 3 d after removal of the CIDR insert with comparable
conception rate to contemporary cycling herd mates. They have also reported
46 and 71 percent pregnancy rate in anoestrus cows and heifers and 61 and 65
percent of first service conception rate in cyclic cows and heifers treated with
CIDR+PG protocol, respectively.
Many previous studies have evaluated the fertility of lactating dairy
cows following Ovsynch protocol and the fertility rates per AI varied from 27
to 39% (Pursley et al., 1997a; Pursley et al., 1997b; Pursley et al., 1998;
Burke et al., 1996; Vasconcelos et al., 1999 and Peters and Pursley, 2003).
Pursley et al. (1995) observed that when PGF2was administered 48 h
and 24 h prior to second GnRH conception rates were 55 and 46%,
respectively. They further observed that pregnancy rates varied in cows
inseminated at fixed time of 0, 8, 16, 24 and 32 h after the second injection of
GnRH in the Ovsynch protocol were 37, 40, 44, 40 and 32%, respectively.
Similarly, Fricke et al. (1998), Stevenson et al. (1996) and Klindworth et al.
(2001) reported 48.9, 41 and 35% conception rates, respectively with Ovsynch
protocol.
Burke et al. (1996) compared the effectiveness of TAI and AI at
detected estrus after Ovsynch protocol in lactating dairy cows and observed
that the conception rates were 30.5 and 29.0%, respectively.
Pursley et al. (1997a) reported that cows in the Ovsynch group that
were above 76 days postpartum had 43.4% pregnancy rate and cows that were
31
60-75 days postpartum had 26% pregnancy rate. They have also reported that
pregnancy rate was 38.9% following TAI after the Ovsynch treatment in
lactating dairy cows which was similar to that of cows bred following double
PG and inseminated 12 h after detection of estrus (37.8%).
In postpartum (43–57 days) lactating dairy cows, Momcilovic et al.
(1998) reported that conception rates with the Ovsynch protocol were 33%
compared to conception rates of only 6% in those inseminated after
spontaneous estrus.Burke et al. (1996), Britt and Gaska, (1998), Momcilovic
et al. (1998) and Stevenson et al. (1999) observed similar pregnancy rates
after TAI following with Ovsynch with that of AI after detected estrus.
Steckler et al. (1999) reported that pregnancy rates in Ovsynch and
Ovsynch+CIDR protocols at day 28 were 49 and 72%, respectively and at day
56 were 37 and 55%, respectively.
Vasconcelos et al. (1999) reported that ovulation after administration
of first GnRH was 87% while the same after second GnRH was 64% in
Ovsynch protocol.In lactating dairy cowsnon-cystic ovarian cows were given
GPG protocol with timed AI after 16 h of second GnRH injection had a
conception and pregnancy rates of 31.5% (Bartolome et al., 2000).
Whisnant et al. (2000) reported that estrus synchronization has become
a reproductive managemental tool for dairy producers where estrus
synchronization controls both the function of corpus luteum and the
development of follicles with viable oocytes which are critical for conception.
They observed that the conception and pregnancy rates from a series of
32
studies using Ovsynch protocol averaged 34.9 and 34.9%,respectively and the
same at breeding during detected estrus after PGF2α averaged 37.7% and
19.8%, respectively.
Fricke and Wiltbank (1999) and Bartolome et al. (2000) recorded that
Ovsynch followed by TAI performed 16-20 h after the second GnRH
treatment yielded 25% pregnancy rates in cows with occurrence of
synchronization of ovulation.
Xu and Burton (2000) reported that conception rate in Ovsynch+CIDR
group was 64.6% and the same was 56.5% when the device was removed one
day after PGF2 injection but the precision of estrus was less in former than
later.
Lamb et al. (2001) and Kawate et al. (2004) reported that pregnancy
rates were varied from 47.7 to 53% after the Ovsynch protocol in beef cows.
Dejarnette et al. (2001) observed that 20% of Ovsynch treated cows
were detected in estrus before 48 h after PGF2injection. High conception
rates of 49 and 72 percent have been reported by Pursley et al. (2001) and
Steckler et al. (2002) in Ovsynch and Ovsynch+CIDR treated postpartum
cows, respectively.
The pregnancy rates for a CIDRbased Ovsynch protocol in beef heifers
ranged from 55.9 to 70.6% (Martinez et al., 2002).
Kim et al. (2003) concluded that the pregnancy rate after TAI
following the inclusion of exogenous progesterone for 7 days and estrogens
on the initiation of treatment in Ovsynch protocol was higher than that after
33
TAI following the Ovsynch protocol (41.2 vs 20.6%) and opined that the
higher pregnancy rate might be due to a decreased incidence of premature
estrus and incomplete luteal regression.Pregnancy rates were recorded to be
65% in PRID+Ovsynch protocol and 30% in Ovsynch (Alnimer and
Lubbadeh, 2003).
Kawate et al. (2004) reported that the conception rate was 72.5 and
47.7% in the Ovsynch+CIDR and Ovsynch group, respectively indicating that
CIDR with the Ovsynch protocol had significantly improved the conception
rates in postpartum suckled Japanese Black beef cows.
Stevenson et al. (2004) reported that the pregnancy rate after Ovsynch
was 27% and in combination with CIDR it was 30.6%.
Kasimanickam et al. (2005) reported 23.9% of conception rate with
Ovsynch protocol in lactating dairy cows.While, Sathiamoorthy et al. (2007)
and Keskin et al. (2010) reported that pregnancy rates were 40 and 48.4%,
respectively in lactating dairy cows.
Sakase et al. (2005) reported that conception rate in Ovsynch and
Ovsynch+CIDR group was 48.6 and 67.7%, respectively in Japanese Black
beef cows.Ui-Hyug Kim et al. (2005) also reported that conception rates were
65% in GnRH + CIDR protocol.
Kasimanickam et al. (2006) reported that the pregnancy rates were
55.6% and 56.5% with Ovsynch+CIDR and in slightly modified
Ovsynch+CIDR protocol, where PGF2 administration and CIDR removal are
delayed by 12 h.
34
Stevenson et al. (2006) reported that conception rates after TAI in
Ovsynch and Ovsynch+CIDR protocols at day 28 were 40 and 50%,
respectively and at day 56 same were 33 and 38%, respectively.
Vasconcelos et al.(2006) concluded that fertility in cattle was
influenced by many factors which included cyclicity, energy balance, heat
stress, parity, level of milk production, diet and diseases.
Aali et al. (2008) reported that the cows which responded to ovulation
after Ovsynch treatment was 49% with an overall pregnancy rate of 31%.
Ambrose (2008) reported that pregnancy rates in Ovsynch+PRID were
61.8% while the same in Ovsynch was 55.6%.
Taponen, (2009) reported that the pregnancy rate was 51.5% in a
modified Ovsynch protocol in which animals without CL (20.7%) after 7 days
of initiation of protocol were rejected.
Murugavel et al. (2010) reported that first service pregnancy rate in
CIDR+PG protocol was 36.36% in anoestrus cows.
Cevik et al. (2010) reported that first and second service pregnancy rate
in lactating dairy cows treated was 76.9 and 53.3%, respectively with
Ovsynch and 100 and 71.4%, respectively with CIDR+PG protocol.
Ozturk et al. (2010) reported that pregnancy rates of cows having
small, medium, or large follicles at the day of second GnRH administration in
the Ovsynch group were 45.5, 28.1 and 5.3%, respectively showing
dramatically reduced pregnancy rates as follicle size increased particularly in
cows with follicles greater than 16 mm.
35
Yildiz, (2010) concluded that Ovsynch did not offer desired pregnancy
rate with FTAI and he had also reported that pregnancy rates for cows treated
with Ovsynch protocol, Ovsynch with post breeding infusion treatment and
control group were 25, 66.7 and 41.7%, respectively which were inseminated
after spontaneous estrus.
Pregnancy rates for Ovsynch+PRID was 39% and Ovsynch alone was
31.7% (Pacala et al., 2010).
Jyothi (2011)observed that thecows inseminated with frozen semen at
the fixed time the first service conception rate was 33.33 (4/12), 41.67 (5/12)
and 41.67 (5/12) percent in crossbred cows synchronized withOvsynch,
Ovsynch+CIDR and CIDR+PG protocols, respectively. While, the second
service conception rateswith Ovsynch,Ovsynch+CIDRand CIDR+PG groups
were16.67 (2/12), 16.67 (2/12) and 00.00 (0/12) percent, respectively.From
this study it was concluded that the overall conception rate in
Ovsynch,Ovsynch+CIDR andCIDR+PG, groups was 50.00 (6/12), 58.33
(7/12) and 41.67 (5/12) percent, respectively. It was concluded that the overall
conception rate in Ovsynch+CIDR was highest when compared to Ovsynch,
CIDR+PG. In another studyRaquel Rodrigues Costa Mello et al. (2013)
reported that pregnancy rate was 50% on using PRID alone.
CHAPTER-III
3. MATERIALS AND METHODS
The present study on “Synchronization of estrus and ovulation in
postpartum acyclic crossbred cows” was carried out at College of Veterinary
Science, Tirupati.
3.1 EXPERIMENTAL ANIMALS
Healthy crossbred cows, with 60 days postpartum interval maintained
under rural conditions were included in the present study. These animals were
fed mainly with paddy straw, dry fodders and concentrate mixture.
3.1.1 Selection of Animals
The crossbred cows were subjected to thorough clinical examination
including rectal palpation and animals with smooth inactive ovaries were
selected. These cows were given presynchronized mineral supplementation
and oral dewormer. Rectal palpations were done twice; spread apart at 12 days
was carried out to confirm acyclicity.
3.2 DESIGN OF THE STUDY
Twenty four cows were divided randomly into three uniform groups
and assigned to Group I (Ovsynch), Group II (Ovsynch+PRID) and Group III
(PRID+PG).
Cows in Group I were administered with 10µg of GnRH (Pregulate,
Virbac Animal Health India Pvt. Limited) intramuscularly on day 0, 500 µg of
cloprostenol sodium (Pregova, Virbac Animal Health India Pvt. Limited) on
day 7 and 10µg of GnRH on day 9, respectively.
36
37
Cows in Group II were administered intramuscularly with 10µg of
GnRH with simultaneous insertion of progesterone releasing intravaginal
device-PRID (TRIU-B, Progesterone Impregnated Intravaginal Device, Virbac
Animal Health India Pvt. Limited) on day 0 (Fig 1 & 2), 500 µg of
cloprostenol sodium intramuscularly at removal of PRID on day 7 and 10µg
of GnRH on day 9, respectively.
In Group III, cows were inserted with PRID and kept in situ for 7 days,
administered 500 µg of cloprostenol sodium at removal of PRID on day 7 and
10µg of GnRH on day 9, respectively. Fixed time artificial insemination (TAI)
was performed 16 to 24 hrs after the end of protocols in all the animals.
3.3 EVALUATION OF ESTRUS
The observations on estrus response, duration of estrus and intensity of
estrus were evaluated (Rao and Rao, 1981).
3.4 SERUM PROGESTERONE ASSAY
Blood sera were collected sterile by making use of vaccutainers from
all the animals for estimation of progesterone on day ‘0’ (day of initiation of
treatment) and at the time of AI and stored at -200C until progesterone assay.
Serum progesterone concentrations were determined by ELISA (enzyme
linked immune sorbent assay) based commercial diagnostic kit (Pathozyme
progesterone, Omega diagnostics Ltd., cotland, UK).
38
39
40
3.5 FERTILITY
Fertility in all the three groups, based on 60 day pregnancy rates by
rectal examination were determined for all the under the study (Noakes et al.,
2009). 3.6 STATISTICAL ANALYSIS
The results were tabulated and analyzed by using One-way ANOVA
and Chi-square which are standard statistical procedures adopted by SPSS
windows package.
CHAPTER-IV
4. RESULTS
The results of the study titled “Synchronization of estrus and ovulation
in postpartum acyclic crossbred cows” were presented in this chapter.
4.1 ESTRUS INDUCTION EFFICIENCY
4.1.1 Estrus response
The estrus response after synchronization of postpartum acyclic
crossbred cows with Group I (Ovsynch), Group II(Ovsynch+PRID) andGroup
III(PRID+PG) protocols was 75.00 (6/8), 100 (8/8) and 87.50 (7/8) percent,
respectively (Table 1 and Fig.6). The highest estrus response is observed
inGroup IIprotocol synchronized cows followed by Group IIIand Group I.
4.1.2 Duration of estrus
The mean duration of estrus in postpartum acyclic crossbred cows with
Group I,Group IIand Group IIIprotocols was 50.62±8.39hrs (ranging from 0 to
72), 68.00±2.61 hrs (ranging from 56 to 72) and 58.63±9.36hrs (ranging from
0 to 72), respectively (Table 1 and Fig.8 ). The difference in the duration of
estrus among all groups was not significant (P>0.05) but duration of estrus in
Group II protocol was longest when compared with other protocols (Table 2).
4.1.3 Intensity of estrus
The postpartum acyclic crossbred cows treated with Group I, Group II
and Group IIIprotocols exhibited intense estrus in 25.00 (2/8), 62.50 (5/8) and
50.00 (4/8) percent of cows and intermediate estrus in 62.50 (5/8), 37.50(3/8)
and 37.50 (3/8) percent of cows, respectively (Table No. 2 and Fig. 7). None
41
42
of theacyclic crossbred cows were detected to be in weak estrus when treated
with Group II protocol, while 12.5 and 12.5 percent of cows were detected to
be in weak estrus when treated with Group I and Group III protocols,
respectively. Highest number of postpartum acyclic crossbred cows exhibited
intense estrus (62.5%) when synchronized with Group II protocol followed by
Group III (50.0%) and Group I (25.0%) protocols.
4.2 SERUM PROGESTERONEASSAY
The mean serum progesterone concentrations on treatment initiation
day i.e. on day 0 were 2.56±1.04ng/ml(ranging from 0.30 to 3.0),1.66±0.24
ng/ml (ranging from 0.7 to 2.6) and 1.43±0.32ng/ml(ranging from 0.3 to
27.4)in Group I, Group II and Group III groups respectively (Table 3).
Concentrations of the same at the time of AI in Group I,Group II and Group
III protocol was 7.60±0.87ng/ml (ranging from 3.8 to 11.4),1.86±0.28ng/ml
(ranging from 0.4 to 3.0) and 2.50±0.65ng/ml (range from 0.5 to 5.6),
respectively (Table 3 and Fig.9 and 10 ). Highest mean progesterone
concentration at AI injection was observed inGroup Ifollowed by Group
IIIand Group II.
The mean serum progesterone concentration on the day of initiation of
treatment were lowest in Group II protocol (1.66±0.24ng/ml)when compared
toGroup I(2.56±1.04ng/ml)followed byGroup III (4.67±3.25ng/ml) protocols.
The difference in the serum progesterone concentrations amongst all
the three synchronization protocols was non-significant (P>0.05), further a
non-significant difference (P>0.05) in the serum progesterone concentrations
43
recorded at day 0 and day of AI for all the three different protocols studied
(Table 3&4).
4.3 Fertility
4.3.1 First service conception rate
All the cows were inseminated with frozen semen at the specified time
of 16-24 hrs after administration of second GnRH. The first service
conception rate (%) was 50.00 (4/8),37.50 (3/8) and 50.00 (4/8) percent in
crossbred acyclic cows synchronized with Group I, Group II and Group III
protocols, respectively (Table 5). The first service conception rate was similar
in Group I and Group III protocols (50.00% each) while it was comparatively
lower in Group II protocol (37.50%).
4.3.2 Second service conception rate
Second service conception rate in Group I, Group II and Group III
groups was 00.00 (0/4), 20.00 (1/5) and 25.00 (1/4) percent, respectively
(Table5). The second service conception rate was slightly higher in Group
IIIprotocol in the present study.
4.3.3 Overall conception rate
The overall conception rate in Group I,Group II and Group III
protocols was50.00 (4/8), 50.00 (4/8) and 62.50 (5/8) percent, respectively
(Table 5 and Fig.11 ). The overall conception rate in Group III was marginally
high when compared to Group I and Group IIprotocols while the differences
were non-significant (P>0.05).
44
Table 1: Effect of synchronization on estrus induction
Groups Estrus
response %
Intensity of estrus % Duration of estrus (hrs) (Mean±SE) Weak Intermediate Intense
Group I 75.0 12.5 62.5 25.0 50.62±8.39NS
Group II 100.0 00.0 37.5 62.5 68.00±2.61NS
Group III 87.5 12.5 37.5 50.0 58.63±9.36NS
Chi-square value
2.28NS 1.09NS 1.35NS 2.35NS
NS: Non-significant
Table 2: Analysis of variance for duration of estrus
Sum of Squares
Degrees of
freedom
Mean Square F Sig
Between groups 1210.083 2 605.42 1.375NS 0.275
Within groups 9239.75 21 439.988
Total 10449.833 23
45
Fig.6: Comparison of estrus response
Fig7: Comparison of intensity of estrus
Fig8: Comparison of duration of estrus
0
20
40
60
80
100
120
Ovsynch Ovsynch + PRID
PRID + PG
Estrus response %
Ovsynch
Ovsynch + PRID
PRID + PG
0
10
20
30
40
50
60
70
ovsynch ovsynch+PRID PRID+PG
weak
intermediate
intense
0
10
20
30
40
50
60
70
80
Ovsynch Ovsynch + PRID PRID + PG
46
Table 3: Serum progesterone (Mean±SE) on day ‘0’ and on day of AI
NS: Non-significant
Table 4: Analysis of variance for means (±SE) of serum progesterone on day ‘0’ and day of AI
Day 0 Day of AI
df Mean Sum of Squares df Mean Sum of
Squares
Between Groups 2 19.130 2 68.780
Within Groups 21 31.370 21 27.333
Total 23 23
S No Groups Day 0 Day of AI
Mean±SE
1 Group I 2.56±1.04 7.60±0.87
2 Group II 1.66±0.24 1.86±0.28
3 Group III 1.43±0.32 2.50±0.65
4 F value 0.610NS 2.516NS
47
Fig 9: Comparison of mean serum progesterone concentrations (ng/ml) in various synchronization protocols on the day of initiation of treatment day ‘0’.
Fig 10: Comparison of mean serum progesterone concentrations (ng/ml) in various synchronization protocols on the day of AI.
0
1
2
3
4
5
Ovsynch Ovsynch + PRID PRID + PG
Day of initiation of treatment ‘0’ day
0
1
2
3
4
5
6
7
8
Ovsynch Ovsynch + PRID PRID + PG
Day of AI Mean ± SE
48
Table 5: Fertility response in crossbred acyclic cows synchronized with 3 different protocols
S No Conception rate (%) Group I Group II Group III Chi-square
value
1 First AI conception 50.00 (4/8) 37.50 (3/8) 50.00 (4/8)
2 Second AI conception 00.00 (0/4) 20.00 (1/5) 25.00 (1/4)
3 Overall conception 50.00 (4/8) 50.00 (4/8) 62.50 (5/8) 0.336NS
NS: Non-significant
Fig. 11 Comparison of conception rates
0
10
20
30
40
50
60
70
ovsynch ovsynch+PRID PRID+PG
ovsynch
ovsynch+PRID
PRID+PG
CHAPTER-V
5. DISCUSSION
In recent times, the fertility in lactating dairy cows was lower than the
desired conception rates and perusal of literature revealed that the conception
rates per AI have been decreased from 66% in 1951 to about 50% in 1975 and
at present it is about 40%. In order to enhance the lowered reproductive
efficiency scientists proposed estrus synchronization programs (Pursley et al.,
1997). Among the range of reproductive technologies available to programme
the reproductive management with the use of estrus and ovulation
synchronization and TAI protocols, three such protocols are compared in the
present study to understand the efficacy of these in inducing or synchronizing
the estrus and ovulation and enhancing the fertility among postpartum acyclic
crossbred cows.
5.1 ESTRUS INDUCTION EFFICIENCY
5.1.1 Estrus Response
In the present study, estrus response in postpartum acyclic crossbred
cows after estrus synchronization was 75.00 (6/8), 100 (8/8) and 87.50 (7/8)
percent in Group I, Group II and Group III, respectively. The highest estrus
response was observed in Group II followed by Group III and Group I.
The estrus response recorded in Group II was the highest when
compared with Group I and Group III. The estrus response (87.50) observed
in Group III was similar that of Pratt et al. (1991). Whereas, Lucy et al.
(2001), Chenault et al. (2003), Murugavel et al. (2010) and Cevik et al. (2010)
49
50
recorded comparatively lowered estrus response (58 to 81.82%) in cows. The
highest estrus response attained in Group II in the present study might be
attributed to the progesterone priming sensitizing the endocrine axis to obtain
better follicular development (Anderson et al., 1996 and Noakes et al., 2009).
Estrus response observed in Group II was 100%. When the estrus
response was compared between Group I and Group II (75% vs 87.5%) there
was no significant difference between the responses, whereas no such
difference was noticed by Stevenson et al. (2004) with Ovsynch+CIDR
(54%). This difference in the estrus response might be due to the inclusion of
exogenous progesterone during the interval between GnRH and PGF2
administration which might have prevented premature estrus and thus had
increased the estrus response (Steckler et al., 2002). In addition induction of
luteolysis with PGF2 on day 7 of the treatment might have caused an
increase in the plasma concentration of estradiol leading to the enhanced
response (Taponen et al., 1999).
Similar percentage of estrus response (75%) in Group I in the present
study was in agreement with the findings of Stevenson et al. (2004) and Cevik
et al. (2010) who recorded 54 and 46.2%, respectively. While, Steckler et al.
(1999) reported higher estrus response (94%) with Ovsynch protocol as
compared to the findings in the present study. This lowered estrus response in
Group I might be due to presence of a small, less estrogenic dominant follicle
(Brantmeier et al., 1987) and also the stage of estrous cycle at the time of
initiation of the protocol in Ovsynch treated cows (Vasconcelos et al., 1999).
Further, during Ovsynch protocol peak concentrations of estrogen secreted by
51
the preovulatory follicle might have prematurely abrogated LH surge induced
by the second GnRH injection (Stevenson et al., 2004). The lowered response
in the present study might be attributed to the nutritional status of animals,
scarcity of fodder during summer, seasonal, breed and locational differences
which might have adversely affected the follicular growth and ovulation
(Dejarnette, 2004).
5.1.2 Duration of Estrus
The mean duration of estrus in this study in postpartum crossbred cows
with Group I, Group II and Group III was 50.62±8.39 hrs (0 to 72),
68.00±2.62 hrs (56 to 72) and 58.63±9.36 hrs (0 to 72), respectively with no
statistical significance between groups.
However, the mean duration of estrus in Group II (68.00±2.62 hrs) was
longer when compared to Group I and Group III in the present study and was
in line with Sathiamoorthy et al. (2007). Whereas, Jyothi (2011) reported
lesser duration with Ovsynch+CIDR when compared to the present study.
The mean duration of estrus 68.00±2.62 hrs in Group II in the present
study was longer (16.2±4.2 and 17.61±0.36 hrs) when compared to the reports
of Kim et al. (2005) and Sakase et al. (2005), respectively. The duration of
estrus in Group III was 58.63±9.36 hrs which was more or less similar to
Group I in the present study.
5.1.3 Intensity of Estrus
During the period of induced estrus all the cows have exhibited the
estrous symptoms but the intensity of estrus symptoms were at varying levels.
The percentage of crossbred cows those exhibited intense, intermediate and
52
weak estrus after synchronization were 12.5, 62.5 and 25.0; 00.0, 37.5 and
62.5 and 12.5, 37.5 and 50.0 respectively in Group I, Group II and Group III
in the present study.
The intense estrus (62.5%) observed in Group II was comparable with
that of Alnimer and Lubbadeh (2003) and Ravikumar et al. (2009). In
contrast, less intensity of estrus was recorded by Fike et al. (1997) in
Ovsynch+PRID protocol. The variations in the intensity of estrus recorded in
the present study, amongst the different protocols might be due to variations
in the methodology of estrus score, parity, breed and environment. To
conclude better estrus characteristics were observed in postpartum acyclic
cows in Group II might be due to the fact that progesterone pretreatment in
postpartum cows sensitized the receptors in the brain, which were then able to
respond to the ovarian estrogen by eliciting the psychic phenomenon
associated with estrus (McDougall et al., 1992).
5.2 SERUM PROGESTERONE ASSAY
The mean serum progesterone concentrations (ng/ml) on day 0 were
2.56±1.04 (0.30 to 7.6), 1.66±0.24 (0.7 to 2.6) and 4.67±3.25 (0.3 to 27.4) in
Group I, Group II and Group III, respectively while the same at the time of AI
were 7.60±0.87 (3.8 to 11.4), 1.86±0.28 (0.4 to 3.0) and 5.51±3.06 (0.5 to
26.6) in Group I, Group II and Group III, respectively. The difference in the
serum progesterone concentrations among protocols and among different days
of collection was non-significant.
53
In the present study no significant difference (P>0.05) was observed in
mean serum progesterone concentration between day 0 and on the day of AI.
On the contrary, Prakash et al. (1995) and Dugwekar et al. (2003) reported
lower serum progesterone values (0.58±0.14 ng/ml) at the time of AI when
compared to those recorded in the present study.
While, Kim et al. (2003) in Ovsynch protocol reported lower mean
serum progesterone concentration (0.96±0.1 ng/ml) on day of AI than the
present study. Similary, Deshmukh et al. (2010) recorded lower levels of
progesterone on day of AI with a mean value of 1.1±0.2 ng/ml which was less
than those recorded in the present study (7.60±0.87 ng/ml) at AI.
In parallel to the present study with Ovsynch, Vasconcelos et al. (1999)
reported a fall in progesterone concentration on day 9 (on the day of AI) with
concentrations 0.50±0.1, 0.40±0.1, 0.20±0 and 0.40±0.1 ng/ml on day 1-4,
day 5-9, day 10-16 and day 17-21, respectively which were less than those
recorded in the present study (7.60±0.87 ng/ml) at the time of AI.
In contrast, Kawate et al. (2004) observed a significant difference in
plasma progesterone concentration between the concentrations on treatment
initiation day and on day of administration of PGF2α. Sathiamoorthy et al.
(2007) also reported the progesterone concentration on day 0 and 9 as
3.84±0.57 and 0.65±0.12 ng/ml, respectively in Ovsynch protocol. Stevenson
et al., (2006) also reported basal concentration of progesterone in 79-100% of
Ovsynch treated cows.
54
In Group I, Group II and Group III no significant difference in the
concentrations of progesterone was observed on day ‘0’ and on the day of AI
which were similar in findings with Kawate et al. (2004). Apparently higher
serum progesterone concentrations on the day of AI were observed in Group I
might have caused ovulatory aberrations leading to reduced conception rate.
5.3 FERTILITY RESPONSE
In the present investigation, the first service conception rate in
postpartum crossbred cows synchronized in Group I, Group II and Group III
was 50.00, 37.50 and 50.00 percent, respectively. Similarly, same protocols
have resulted overall conception rate of 50.00, 50.00 and 62.50 percent,
respectively in postpartum acyclic crossbred cows with no significant
difference between groups.
The first service conception rate and overall conception rate (62.5%) in
postpartum crossbred cows in Group III was highest in the present study was
in support with the findings of Lucy et al. (2001) and Cevik et al. (2010). In
contrast, Murugavel et al. (2010) and Stevenson et al. (2004) reported lower
conception rates of 36.36 and 30.6% with CIDR+PG, respectively in cows
compared with those observed in the present study might be due to
administration of progesterone during late luteal phase of the estrous cycle
might have caused development of persistent dominant follicles in the absence
of a functional CL and subsequent ovulation of aged and unhealthy oocytes in
some of the cows (Ahmad et al., 1995; Revah and Butler, 1996; Roche et al.,
1999 and Lucy et al., 2001) and resulted in a poor quality embryos and
55
embryonic deaths with a reduction in a conception rate at synchronized estrus
(Mihm et al., 1994; Ahmad et al., 1995 and Chenault et al., 2003).
While, the higher conception rates in cows synchronized in Group III
(62.5%) than the Group II and Group I protocols observed in the present study
might be due to reasons that ovarian acyclicity during anoestrus was related to
low level of pituitary and gonadotrophic hormones and thus progesterone
treatment in these animals might be effective for induction of estrus and also
justified that Progesterone+GnRH treatment was further more effective as
progesterone would act as an artificial CL, while its withdrawal removed the
negative feedback on hypothalamus and promoted estrus with follicular
development leading to ovulation and thus conception on fixed time AI
(Anderson et al., 1996; Imwalle et al., 1998 and Pawar et al., 2012).
Ovsynch protocol in the present study has resulted in first service
conception rates as 50.00 percent and none of the remaining animals
conceived on second AI. The overall conception rate with Ovsynch (%) in
postpartum crossbred cows in the present study is in agreement with the
findings (47.7 to 53%) of Geary et al. (2001), Lamb et al. (2001), and
Klindworth et al., (2001), Kawate et al. (2004), Taponen (2009) and Keskin et
al. (2010), However, Pursley et al. (1995), Pursley et al. (1997), Burke et al.
(1996), Stevenson et al. (1996), Momcilovic et al. (1998), Fricke and
Wiltbank (1999), Bartolome et al. (2000), Kim et al. (2003), Kasimanikam et
al. (2005), Stevenson et al. (2006), Sathiamoorthy et al. (2007), Aali et al.
(2008) and Yildiz (2010) observed lower conception rate (20.6 to 41%) in
56
cows than the present study. This higher conception rates obtained with
Ovsynch might be due to reason that the first GnRH might have initiated the
growth of a new wave of follicles (Macmillan and Thatcher, 1991 and
Twagiramungu et al., 1994) followed by emergence and selection of a
dominant follicle that becomes preovulatory within 9 days of emergence and
the most fertile ova (Savio et al., 1993).
These variations observed by various authors in the conception rates
with Ovsynch protocol might be due to the difference in response to the first
GnRH administration and also cyclicity status of the animal at the time of
initiation of the treatment (Thatcher et al., 2002 and Bello et al., 2006). The
estrus stage at the time of first injection of GnRH in the Ovsynch protocol is
particularly critical because the proportion of follicles ovulating in response to
the first GnRH injection and the synchrony of ovulation following the second
GnRH injection may affect the pregnancy rate (Vasconcelos et al., 1999).
Premature follicular maturation before 2nd GnRH, ovulation before TAI
(Moreira et al., 2000a) and inability of 1st GnRH to turn over the dominant
follicle late in the estrous cycle leading to premature estrus (Geary et al.,
2000) might also have decreased the conception rate. Further, the dominant
follicle present at the time of second GnRH treatment might have failed to
express LH receptors leading to failure of ovulation suggesting that GnRH did
not induce ovulation due to asynchronous wave emergence and/or a small
dominant follicle without LH receptors (Colazu et al., 2004). Further, the
second GnRH which resulted in ovulation and the subsequent CL formed
57
might have produced lesser progesterone leading embryonic mortality
resulting in reduced conception rate (Moreira et al., 2000a). Lowered
conception rate observed in Ovsynch protocol along with higher levels of
serum progesterone at the time of AI might be suggestive of incomplete luteal
regression following the injection of PGF2 (Burke et al., 1996; Peters et al.,
1999; Moreira et al., 2000; Lamb et al., 2001and Kim et al., 2003).
To correct the above premature follicular maturation and ovulatory
problems supplementation of progesterone through PRID was attempted to
enhance the blood progesterone concentrations until PGF2 administration
and conception rate. Group II cows, in the present study the first service,
second service and overall conception rates in postpartum crossbred cows
were 37.00, 20.00 and 50.00 percent, respectively. These findings gained
support from the reports of Steckler et al. (1999) and Kasimanikam et al.
(2006) who have recorded conception rates of 55.0 and 55.6%, respectively.
However, Xu and Burton (2000), Pursley et al. (2001), Steckler et al. (2002),
Kawate et al. (2004) and Sakase et al. (2005) observed higher conception
rates (64.6 to 72.5%) than those recorded in the present study in crossbred
cows. In contrast, Kim et al. (2003) and Stevenson et al. (2006) reported
lower conception rates (41.2 and 38%).
The improved and higher conception rate observed in this study in
Group III when compared with previous studies might be due to the
synchrony between luteolysis, ovulation and TAI and the supplementation of
progesterone through PRID (Steckler et al., 2002 and Stevenson et al., 2006).
58
Further, the low progesterone concentration recorded in this study at the time
of AI expect in Ovsynch group might have caused marginal enhancement in
the conception rate (Lamb et al., 2001). The enhanced conception rates with
PRID+PG protocol might be due to increased concentrations of estradiol-17
beta in cows treated previously with progesterone that caused release of more
LH after GnRH resulting in increased ovulatory response and in turn
conception rates (Thompson et al., 1999). In addition, supplementation of
progesterone with GnRH would reduce the dominant follicle size at the time
of PGF2 treatment and improve the fertility, apparently due to the reduced
incidence of persistence of follicle (Martinez et al., 2001). The highest
conception rates in the present study also might be due to creation of a
congenial environment in the uterus since progesterone concentrations during
one estrous cycle affects the endometrial morphology in the subsequent cycle
and maintains the pregnancy effectively (Albalancy et al., 1997). Further,
Pacala et al. (2010) opined that progestagen treatment mimed the luteal phase
of the estrous cycle and thus recommended their use for heat induction as they
stimulated the hypothalamus-pituitary-ovarian axis.
It is concluded from the present study that supplementation of
exogenous progestagens like PRID to Ovsynch protocol had helped the cows
to exhibit better estrus parameters due to progesterone priming. Further, it was
opined that PRID+PG (Group III) protocol yielded apparently higher
conception rates compared to Ovsynch+PRID (Group II) and Ovsynch (Group
I) protocols. Under field conditions in the treatment of postpartum acyclic
59
crossbred cows estrus parameters had little significance when compared to
achieving optimum conception rate with a cost effective protocol like
PRID+PG (Group III) which required one dose less of GnRH hormone which
is economical to the farmers. However, systematic studies on a large sample
of cows are warranted before drawing concrete conclusions.
CHAPTER-V1
6. SUMMARY
The present study was done on 24 healthy postpartum acyclic crossbred
cows maintained under diverse managemental conditions to study the efficacy
of different synchronization protocols viz., Ovsynch (Group I),
Ovsynch+PRID (Group II) and PRID+PG (Group III) based on estrus
response, duration of estrus, intensity of estrus, serum progesterone
concentration and conception rate.
The estrus response in Group I, Group II and Group III was was 75.00
(6/8), 100 (8/8) and 87.50 (7/8) percent, respectively. The highest estrus
response is observed in Group II synchronized cows followed by Group III
and Group I.
The mean duration of estrus in postpartum acyclic crossbred cows in
Group I, Group II and Group III was 50.62±8.39 hrs, 68.00±2.61 hrs and
58.63±9.36 hrs, respectively. The difference in the duration of estrus among
all groups was not significant (P>0.05) but duration of estrus in Group II was
longest when compared with other protocols.
The postpartum acyclic crossbred cows treated in Group I, Group II
and Group III was exhibited intense estrus in 25.00, 62.50 and 50.00 percent
of cows and intermediate estrus in 62.50, 37.50 and 37.50 percent of cows,
respectively. None of the acyclic crossbred cows were detected to be in weak
estrus when treated with Ovsynch+PRID protocol, while 12.5 and 12.5
percent of cows were detected to be in weak estrus when treated with
60
61
Ovsynch and PRID+PG protocols, respectively. Highest number of
postpartum acyclic crossbred cows exhibited intense estrus (62.5%) when
synchronized with Ovsynch+PRID protocol followed by PRID+PG (50.0%)
and Ovsynch (25.0%) protocols.
The mean serum progesterone concentrations on treatment initiation
day i.e. on day 0 were 2.56±1.04 ng/ml, 1.66±0.24 ng/ml and 1.43±0.32 ng/ml
in in Group I, Group II and Group III, respectively. Concentrations of the
same at the time of AI were 7.60±0.87 ng/ml, 1.86±0.28 ng/ml and 2.50±0.65
ng/ml, respectively. Highest mean progesterone concentration at AI injection
was observed in Ovsynch followed by PRID+PG and Ovsynch+PRID.
The mean serum progesterone concentration on the day of initiation of
treatment were lowest in Ovsynch+PRID protocol (1.66±0.24 ng/ml) when
compared to Ovsynch (2.56±1.04 ng/ml) followed by PRID+PG (4.67±3.25
ng/ml) protocols.
The difference in the serum progesterone concentrations amongst all
the three synchronization protocols was non-significant (P>0.05), further a
non-significant difference (P>0.05) in the serum progesterone concentrations
recorded at day 0 and day of AI for all the three different protocols studied.
All the cows were inseminated with frozen semen at the specified time
of 16-24 hrs after administration of second GnRH. The first service
conception rate (%) was 50.00, 37.50 and 50.00 percent in crossbred acyclic
cows synchronized in Group I, Group II and Group III, respectively. The first
service conception rate was similar in Group I (Ovsynch) and Group III
62
(PRID+PG) (50.00% each) while it was comparatively lower in
Ovsynch+PRID protocol (37.50%). Second service conception rate in
Ovsynch, Ovsynch+PRID and PRID+PG groups was 00.00, 20.00 and 25.00
percent, respectively. The second service conception rate was slightly higher
in PRID+PG protocol in the present study. The overall conception rate in
Ovsynch, Ovsynch+PRID and PRID+PG protocols was 50.00, 50.00 and
62.50 percent, respectively.
From the present study it was concluded that Ovsynch+PRID protocol
was effective with regards to estrus parameters while the overall conception
rate in PRID+PG was marginally high when compared to Ovsynch and
Ovsynch+PRID protocols. However, the present study was targeted to achieve
synchronized estrus in postpartum acyclic cows with normal conception rate
by adopting fixed time artificial insemination. Under field conditions in the
treatment of postpartum acyclic crossbred cows estrus parameters had little
significance when compared to achieving optimum conception rate with a cost
effective protocol like PRID+PG (Group III) which required one dose less of
GnRH hormone which is economical to the farmers.
LITERATURE CITED
Aali M, Pretheeban T, Giritharan G and Rajamahendran R 2008 Pregnancy rates and peripheral progesterone levels following Ovsynch or CIDR ovulation synchronization/timed artificial insemination protocols in postpartum dairy cows. Canadian Journal of Animal Science. 457-461.
Ahmad N F, Sherick N, Butcher R L and Inskeep E K 1995 Effect of
persistent follicles on early embryonic losses in beef cattle. Biologyof Reproduction. 52:1129-1135.
Albalancy S. A, Nyska A, Kaim M, Rosenberg M, Folman Y and Woltenson
D 1997 Delayed effect of progesterone on endometrial morphology in dairy cows. Animal Reproduction Science 48 : 159-174.
Alnimer M and Lubbadeh W 2003 Effect of using Progesterone Releasing
Intravaginal Device with ovsynch program on reproduction in dairy cattleduring summer season. Asian-Australian Journal of Animal Science. 16:1268-1273.
Amer H A 2008 New trends for oestrus synchronization in lactating dairy
cows. Research Journal of Dairy Sciences 2(1) : 16-21. Ambrose D J, Emmanuel D G V, Colazo M G and Kastelic J P 2008
Pregnancy rates to Timed Artificial Insemination in Holstein Heifers givenProstaglandinF2α twenty-four hours before or concurrent with removal of an Intravaginal Progesterone-Releasing Insert. Journal of Dairy Science. 91 :2678-2683.
Anderson L H, McDowell C M and Day M L 1996 Progestin-induced puberty
and secretion of luteinizing hormone in heifers. Biology of reproduction 54:1025.
Bartolome J A, Archbald L F, Morresey P, Hernandez J, Tran T, Kelbert D,
LongK, Risco C A and Thatcher W W 2000 Comparision of synchronizationof ovulation and induction of estrus as therapeutic strategies for bovineovarian cysts in the dairy cows. Theriogenology. 53:815-825.
Baruselli P S, Ferreira R M, Sales J N S, Gimenes L U, Sa Filho, Martins C
M, Rodrigues C A, Bo G A 2011 Timed embryo transfer programs for management of donor and recipient cattle. Theriogenology 76 : 1583-1593.
63
64
Beal W E, Chenault J R, Day M L and Corah L R 1988 Variation in conception rates following synchronization of estrus with melengesterol acetate and prostaglandin F2α. Journal of Animal Science 66 : 599.
Bello N M, Steibel J P and Pursley J R 2006 Optimizing ovulation to first
GnRHimproved outcomes to each hormonal injection of ovsynch in lactatingdairy cows. Journal of Dairy Science. 89:3413-3424.
Borman J M, Radcliff R P, McCormack B L, Kojima F N, Patterson D J,
Macmillan K L and Lucy M C 2003 Synchronization of oestrus in dairy cows using prostaglandin F2α, Gonadotrophin-releasing hormone and oestradiol cypionate. Animal Reproduction Sciences 76: 163-176.
Brantmeier S A, Bellin M E, Boehm S K, Bushmeyer S M, Kubajak C L,
Dentine M R 1987 Influence of stage of cycle, corpus luteum location, follicle size and number of large follicles on estradiol-17 β concentrations in bovine follicle. Journal of Dairy Science. 70 : 2138-2144.
Britt J S and Gaska J 1998 Comparison of two estrus synchronization
programmes in a confinement-housed dairy herd. Journal of American Veterinary Medical Association 212 : 210-212.
Burfening P G, Anderson P C, Kankie R A, Williams J and Fried Rich R L
1978 Synchronization of oestrus with PGF in beef cattle. Journal of Animal Science. 47 : 999.
Burke J M, De la Sota R L, Risco C A, Staples C R, Schmitt E J P and
ThatcherW W 1996 Evaluation of timed insemination using a gonadotropin- releasing hormone agonist in lactating dairy cows. Journal of Dairy Science. 79:1385-1393.
Butler S A A, Atkinson P C, Boe-Hansen G B, Burns B M, Dawson K, Bo G
A and McGowan M R 2011 Pregnancy rates after-fixed artificial insemination of Brahman heifers treated to synchronize ovulation with low-dose intravaginal progesterone releasing devices, with or without eCG. Theriogenology. 76:1416-1423.
Callesen H, Greve T and Hyttel P 1986 Preovulatory endocrinology and oocyte
maturation in super ovulated cattle. Theriogenology 25 : 71-86. Callesen H, Greve T and Hyttel P 1987 Premature ovulations in super
ovulated cattle. Theriogenology 28 : 155-166.
65
Callesen H, Greve T and Hyttel P 1993 Estrus characterization in super
ovulated cattle. Theriogenology 40 : 1243-1250. Cavalieri J, Hepworth G and Macmillan K L 2004 Ovarian follicular
development in Holstein of estrus with oestradiol benzoate and an intravaginal progesterone releasing insert for 5-9 days and duration of the oestrous cycle and concentrations of progesterone following ovulation. Animal Reproduction Science. 81:177-193.
Cevik M, Selcuk M and Dogan S 2010 Comparison of pregnancy rates after
timed artificial insemination in Ovsynch, heatsynch and CIDR-Based Synchronization Protocol in Dairy Cows. Kafkas Universitesi Veteriner Fakultesi Dergisi16:85-89.
Chenault J R, Boucher J F and Hafs H D 2003 Synchronization of estrus in
beef cows and beef and dairy heifers with intravaginal progesterone inserts and prostaglandin with or without Gonadotropin-Releasing hormone. The professional Animal Scientist. 19:116-123.
Coleman D A, Bartol F F, Spencer T E, Floyd J G, Wolfe D F and
Brendemuehl J P 1991 Effects of potent GnRH agonist on hormonal profiles, synchronization of estrus and fertility in beef cattle. Journal of animal science 69 : 396.
DeJarnette J M, Salverson R R and Marshall C E 2001 Incidence of premature
estrus in lactating dairy cows and conception rates to standing estrus or fixed time inseminations after synchronization using GnRH and PGF2α. Animal Reproduction Science. 67:27-35.
Deshmukh Y D, Markandeya N M, Chaudhari R J and Deshmukh V V 2010
Progesterone profile in two different protocols of estrus synchronization in postpartum Red Kandhari cows. Indian Journal of Animal Reproduction 31 (2) : 37-39.
Diskin M G, Austin E J and Rochi J F 2002. Exogenous hormonal manipulation of ovarian activity in cattle. Domestic Animal Endocrinology 23 : 211-228.
Dugwekar Y G, Patel D M and Sarvaiya N P 2003 synchronization of estrus in jersey cows treated with PGF2α by two different routes. The Indian Journal of Animal Reproduction 24 (2): 163-164.
Fike K E, Day M L, Inskeep E K, Kinder J E, Lewis P E, Short R E and Hafs H D 1997 Estrus and luteal function in suckled beef cows that were anestrous when treated with an intravaginal device containing progesterone with or without a subsequent injection of estradiol benzoate. Journal of Animal Science 75 : 2009-2015.
66
Folman Y, Kaim M, Herz Z and Rosenberg M 1990 Comparison of methods for the synchronization of estrus cycles in dairy cows. 2. Effects of progesterone and parity on conception. Journal of Dairy Science. 73:2817-825.
Fonseca F A, Britt J F, McDanial B T, Wilk J C and Rakes A H 1983
Reproductive traits of Holstein and Jerseys effect of age, milk yield and clinical abnormalities on involution of cervix and uterus, ovulation, estrus cycles, detection of estrus, conception rates and days open. Journal of Dairy Science. 66 : 1128-1147.
Fortune J E, Sirois J and Quirk S M 1988 The growth and differentiation of
ovarian follicles during the bovine estrus cycle. Theriogenology. 29 : 95-109.
Fricke P M and Wiltbank M C 1999 Effect of milk production on the
incidence of double ovulation in dairy cows. Theriogenology. 52:1133-1143.
Gabor G Y, Kastelic J P, Pinter S, Szasz F, Szigeti and Solymosi N 2002
Improving reproductive performance in lactating dairy cows by synchronizing ovulation or inducing oestrus. Acta Veterinaria Hungarica.50:231-234.
Galvao K N and Santos J M P 2010 Factors affecting synchronization and
conception rates after the ovsynch protocol in lactating Holstein dairy cows. Reproduction in Domestic Animals. 45 : 439-446.
Garverick H A, Elmore R G, Vaillan Court D H, and Sharp A J 1998 Ovarian
response to gonadotropin releasing hormone in postpartum dairy cows. Animal Journal of Veterinary Research. 41:1582-1585.
Geary T W, Whittier J C, Hallford D M and MacNeil M D 2001 Calf removal
improves conception rates to the Ovsynch and Co-synch protocols. Journal of Animal Science. 79:2536-2541.
Hansel W, Malven P V and Black D L 1961 Estrous cycle regulation in the bovine. Journal of Animal Science 20 : 621-625.
Heersche G, Jr. Kiracofe G H, DeBenedetti R C, Wen S and Mckee R M 1979 Synchronization of estrus in beef heifers with a norgestomet implant and prostaglandin- F2α. Theriogenology 11: 197.
Hittinger M A, Ambrose J D and Kastelic J P 2004 Luteolysis, onset of estrus and ovulation in Holstein heifers given prostaglandinF2α concurrent with or 24hr prior to, removal of an intravaginal progesterone-releasing device. Canadian Journal of Veterinary Research. 68:283-287.
67
Imwalle D B, Patterson D J and Schillo K K 1998 Effect of melengestrol
acetateon onset of puberty, follicular growth and patterns of lutenizing hormone secretion in beef heifers. Biology of Reproduction58:1432.
Islam R 2011 Synchronization of estrus in cattle: A Review. Veterinary world
4(3):136-141. Jagir Singh, Ghuman S P S, Honparkhe M and Singh N 2009 Investigations
ondominant follicle development, estrus response, ovulation time, and fertility in PRID-Treated anestrous buffalo heifers. The Indian Journal of Animal Sciences 79 (8) : 34-45.
Jyothi K 2011 Efficacy of different estrus synchronization protocols on
fertility in postpartum crossbred cows. Thesis submitted to Sri Venkateswara Veterinary University.
Kasimanickam R, Collins J C, Wuenschell J, Currin J C, Hall J B and Whittier
DW 2006 Effect of timing of prostaglandin administration, controlledinternal drug release removal and gonadotropin releasing hormoneadministration on pregnancy rate in fixed-time AI protocols in crossbred Angus cows. Theriogenology 66:166-172.
Kasimanickam R, Cornwell J M and Nebel R L 2004 Fertility following
fixed-time AI or insemination at observed estrus in Ovsynch and Heatsynch programs in lactating dairy cows. Theriogenology 63:2550-2559.
Kawate N, Itami T, Choushi T, Saitoh T, Wada T, Matsuoka K, Uenaka
K,Tanaka N, Yamanaka A, Sakase M, Tamada H, Inaba T and Sawada T 2004 Improved conception in timed-artificial insemination using a progesterone-releasing intravaginal device and Ovsynch protocol in postpartum suckled Japanese Black beef cows. Theriogenology 61:399-406.
Keskin A, Yilmazbas-Mecitoglu G, Gumen A, Karakaya E, Darici R, Okut H
2010 Effect of hCGvs GnRH at the beginning of the Ovsynch on first ovulation and conception rates in cyclic lactating dairy cows. Theriogenology 74:602-607.
Kim U H, Gook-Hyun Suh and Dong- Soo Son 2003 A progesterone- based
timed AI protocol more effectively prevents premature estrus andincomplete luteal regression than an Ovsynch protocol in lactating Holstein cows. Theriogenology 60:809-817.
68
Klindworth H P, Hoedemaker M, Burfeindt D and Heilkenbrinker T 2001 Ovulation synchronization (ovsynch) in hochleistenden milchviehherden. I. Fruchtbarkeitsparameter, body condition score and plasma progesterone. Konzentration DTSCH Tierarztl. Wschr. 108:11-19.
Kojima F N, Salfen B E, Bader J F, Ricke W A, Lucy M C, Smith M F and
Patterson D J 2000 Development of an estrus synchronization protocol for beef cattle with short- term feeding of melengestrol acetate, 7-11 synch. Journal of Animal Science 78 : 2186-2191.
Kumar M, Shiv Saran Pant, Ramsharan Ram, Salendra Kumar and Gupta PK
2014 Therapeutic efficacy of levofloxacin along with vitamin E for themanagement of repeat breeding syndrome in cow under field condition. International Journal of Veterinary Science 155-157.
Kyle S D, Callahan C J and Allrich R D 1992 Effect of progesterone on the
expression of estrus at the first postpartum ovulation in dairy cattle. Journal of Animal Science 75 : 1456-1460.
Lamb G C, Dahlen C R, Larson J E, Marquezini G and Stevenson J S
2010Control of the estrus cycle to improve fertility for fixed-time artificial insemination in beef cattle: A review. Journal of Animal Science 88:E181-E192.
Lamb G C, Stevenson J S, Kesler D J, Garverick H A, Brown D R and Salfen
B E 2001 Inclusion of an intravaginal progesterone insert plus GnRH andprostaglandin for ovulation control in postpartum suckled beef cows. Journal of Animal Science 79:2253-2259.
Lane E A, Austin E J, Roche J F and Crowe M A 2000 The effect of
EstradiolBenzoate or a synthetic Gonadotropin Releasing Hormone used at the start of a progesterone treatment on estrus response in cattle. Theriogenology 56:79-90.
Larson L L and Ball P J H 1992 Regulation of estrous cycles in dairy cattle: a
review. Theriogenology 38 : 255. Lucy M C 2001 A.D.S.A Foundation Scholar award, Reproduction loss in
high producing dairy cattle where will it end? Journal of Dairy Science 84:1277.
Macmillan KL 2010 Recent advances in the synchronizing of estrus
andovulation in dairy cows. Journal of Reproduction and Development 56:S42-S47.
69
Martinez M F, Kastelic J P, Adams G P and Mapletoft R J 2001 The use of GnRH or estradiol to facilitate fixed time insemination in an MGA based synchronization regimen in beef cattle. Animal Reproduction Science. 67:221-229.
Mayne C S, McCoy M A, Lennox S D, Mackey D R, Verner M and Catney D
C 2002 Fertility of dairy cows in Norther Ireland. Veterinary Record 150 : 707-713.
McDougall, Burke C R, MacMillan and Williamson N B 1992 The effect of
pretreatment on the estrous response to estradiol-17β benzoate in the postpartum dairy cows. Proceedings of the New Zealand Society of Animal Reproduction 52:157-160.
Mihm M, Curran N, Hyttel P, Boland M P and Roche J F 1994 Resumption of
meiosis in cattle oocytes from preovulatory follicles with a short and a long duration of dominance. Journal of Reproduction and Fertility. Abstr.Ser. 13:14.
Momcilovic D, Archbald L F, Walters A, Tran T, Kelbert D, Risco C and
Thatcher W W 1998 Reproductive performance of lactating dairy cowstreated with gonadotropin –releasing hormone(GnRH) and/orprostaglandin F2α (PGF2α) for synchronization of estrus and ovulation. Theriogenology 50:1131-1139.
Moreira F, Risco C, Pires M F A, Ambrose J D, Drost M, DeLorenzo M
andThatcher W W 1999 Effect of body condition on reproductive efficiency of lactating dairy cows receiving a timed insemination. Theriogenology 53:1305-1319.
Mozaffari N, Hamali H and Jafari R 2014 Effects of two different protocols:
injections of progesterone vs. injection of GnRH+PGF2αa on the onset of estrus in dairy cows with postpartum anestrous. International journal of Advanced Biological and Biomedical Research 2 (1) :146-150.
Murugavel K, Antoine D and Raju M S 2010 Effect of eCG on fertility in
CIDR treated anusmores cows. Indian Veterinary Journal 87:670-672.
Nicolae Pacala, Nicolae Corin, Ioan Bencisk, Dorel Dronca, Ada Cean,
Alexandra Boleman, Valeriu Caraba and Stefan Papp 2010 Stimulation of the reproductive functions at acyclic cows by ovsynch and PRID/eCG. Animal Science and Biotechnologies 43(1):317-320.
70
Noakes E. David, Timothy J. Parkinson and Gary C.W.England 2009 Text book of Veterinary Reproduction and Obstetrics. Chapter- Anoestrus and other functional causes of infertility, Page no: 425-429.Ninth edition. Saunders Elsevier, London.
Ozturk O A, Cirit U, Baran A and Ak K 2009 Is Doublesynch protocol a new
alternative for timed artificial insemination in anestrus dairy cows. Theriogenology 73:568-576.
Pankowski J W, Galton D M, Erb H N, Guard C L and Grohn Y T 1995 Use
of prostaglandin F2α as a postpartum reproductive management tool for lactating dairy cows. Journal of Dairy Science 78 : 1477-1488.
Pawar S A, Markandeya N M, Sawale A G and Kasbe R D 2012 Studies on
induction of estrous in local anestrous cows with progesterone primed GnRH and progesterone treatment. Indian Journal of Animal Reproduction 33(2):84-86.
Perry G A, Smith M F, Lucy M C, Green J A, Parks J E and McNeill M D
2005 Relationship between follicle size at insemination and pregnancy success. Proceedings of the National Academy of Science USA, 102 : 5268-5273.
Peters AR, Mawhinney I, Drew SB, Ward SJ, Warren MJ and Gordon PJ
1999Development of a gonadotrophin-releasing hormone and prostaglandinregimen for the planned breeding of dairy cows. Veterinary Record 145(18):516-521.
Prakash N, Ramachandran S G and Narayana K 1995 Endocrine profiles
during luteolysis induced by low dose of cloprostenol in crossbred HF cows and heifers. Indian Journal of Animal Reproduction 16 : 9-11.
Pratt S L, Spitzer J C, Burns G L and Plyler B B 1991 Luteal function,
anestrous response and pregnancy rate after treatment with norgestomet and various dosages of estradiol valerate in suckled cows. Journal of Animal Science 69:2721-2726.
Pursley J R,Mee M O and Wiltbank M C 1995 Synchronization of ovulation
indairy cows using PGF2α and GnRH. Theriogenology 44:915-923. Pursley J R, Wiltbank M C, Stevenson J S, Ottobre J S, Garverick H A and
Anderson L L 1997b Pregnancy rates per artificial insemination for cows and heifers inseminated at synchronized ovulation or synchronized estrus. Journal of Dairy Science 80:295-300.
71
Rajamahendran R and Thamotharam M 1991 Effect of progesterone releasing intravaginal device (PRID) on fertility in the post-partum buffalo cow.Animal Reproduction Science 6:111-118.
Rao S V and Rao A R 1981 Estrus behavior and ovarian activity of cross bred
heifers. Indian Veterinary Journal 58 : 881-884. Raquel Rodrigues Costa Mello, Marco Roberto Bourg de mello, Joaquim
Esquerdo Ferreira, Ana Paula Toledo Barbosa da Silva, Leandro Mendes Mascarenhas, Bernardo Janella, Ferreira da Silva, Beatriz de Oliveira Cardoso, Helcimar Barbosa Palhano 2013 Reproduvtive parameters of Sindhi cows (Bos Taurus indicus) treated with two ovulation synchronization protocols. Revista Brasileira de Zootecnia 42 : 414-420.
Ravikumar K, Asokam S A and Veera Pandian C 2009 Inclusion of CIDR in
ovsynch protocol to improve fertility in postpartum subestrum buffaloes. Indian Journal of Animal Reproduction 30 : 1.
Rhodes F M, McDougall S, Burke C R, Verkerk G A and Macmillan K L
2003 Treatment of cows with an extended postpartum anestrous interval. Journal of Dairy Science 86 (6) : 1876-1894.
Roche J F, Austin E J, Ryan M, Roorky M O, Mahim M and Diskin M G
1999 Regulation of follicle waves to maximize fertility in cattle. Journal of Reproduction and Fertility 54:61-71.
Ryan D P, Snijders S, Yaakub H and O’Farrell K J 1995 An evaluation of
estrous synchronization programs in reproduction management of dairy herds. Journal of Animal Science 73:3687.
Sakase M, Seo Y, Fukushima M, Noda M, Takeda K, Ueno S, Sawada T
andKawate N 2005 Effect of CIDR-based protocols for timed-AI on the conception rate and ovarian functions of Japanese Black beef cows in the early postpartum period. Theriogenology 64:1197-1211.
Sathiamoorthy T, Parthasarathy R and Karthircalvan M 2007 Estrus response
andfertility rate in PGF2α, CIDR and Ovsynch treated cows. Indian Veterinary Journal 84:600-602.
Savio J D, Thatcher W W, Morris G R, Entwistle K, Drost M and Mattiacci M
R 1993 Effects of induction of low plasma progesterone concentrations with a progesterone- releasing intravaginal device on follicular turnover and fertility in cattle. Journal of Reproduction and Fertility 98 : 77-84.
72
Schmitt E J, Diaz T, Drost M and Thatcher W W 1996 Use of a Gonadotrophin releasing hormone agonist or hCG for timed insemination in cattle. Journal of Animal Science 74 : 1084-1091.
Seidel G E Jr 1995 Reproductive biotechnologies for profitable beef production. Proceedings Beaf Improvement Federation P. 28-39.
Shams ZH, Kharche KG, Thakur MS 1991 The efficacy of gonadotrophin releasing hormone (receptal) alone and in combination for oestrusinduction in anoestrus crossbred cows. Indian Journal of Animal Reproduction 12 : 175.
Smith S T, Ward W R and Dobson H 1998 Use of ultrasound to help to
predict observed oestrus in dairy cows after the administration of prostaglandin F2α. Veterinary Record 142 : 271-274.
Soto B E, Portillo Martinez G, De Ondiz A, Rojas N, Soto Castillo G,
Ramirez Iglesia L and Perea Ganchou F 2002 Improvement of reproductive performance in crossbred Zebu anestrous primiparous cows by treatment with norgestomet implants or 96 h calf removal. Theriogenology 57 : 1503-1510.
Soto B E, Gonzalez R, Portillo G and Ramirez L 1998 Use of CIDR
intravaginal device for the treatment of anoestrus in dual purpose crossbred cows. Revista Cientifica 8 : 84- 86.
Steckler T L, Lock T F, Mcloy G C and Kesler D J 2002 Efficacy of Ovsynch
alone or in combination with intravaginal progesterone inserts in dairy cows. (Available at: http://www. Selectsires.com/selection/2002-q3-page7- 0.html) accessed May 2003.
Stevenson J S, Pursley J R, Garverick H A, Fricke P M, Kesler D J, Ottobre J
Sand Wiltbanks M C 2006 treatment of cycling and noncycling lactating dairy cows with progesterone during ovsynch. Journal of Dairy Science 89:2567-2578.
Stevenson J S, Kobayashi Y and Thompson K E 1999 Reproductive performance of dairy cows in various programme breeding system including ovsynch and combinations of Gonadotropin releasing hormone and prostaglandin F2α. Journal of Dairy Science 82 : 506-515.
Taponen J 2009 Fixed-time artificial insemination in beef cattle. Acta veterinaria Scandinavica Research 51 : 48.
Thatcher W W 2001 Current concepts for estrus synchronization and timedinsemination. In:Proceedings of the 34th Annual Convention of the American Association of Bovine Practitioners, Vancouver, Canada 34 : 95-105.
73
Thatcher W W, Drost M, Savio J D,Macmillan K L, Entwistle K W, Schmitt
E J, De la Sota R L andMorris G R1993 New clinical uses of GnRH and its analogues in cattle. Animal Reproduction Science, 33:27-49.
Thompson K E, Stevenson J S, Lamb G S, Grieger D M and Loest C A 1999
Follicular, hormonal and pregnancy responses of early postpartum suckled beef cows to GnRH, Norgestomet and prostaglandin F2α. Journal of Animal Science 77 : 1823-1832.
Twargiramungu H, Guilbault L A and Dufour J J 1995 Synchronization of
ovarian follicular waves with a Gonadotropin releasing hormone agonist to increase the precision of estrus in cattle: A review. Journal of Animal Science 73:3141-3151.
Vav werven T, Waldeck F, Souza A H, Floch S and Englebienne M 2013
Comparision of two intravaginal progesterone releasing devices (PRID-Delta vs CIDR) in dairy cows: Blood progesterone profile and field fertility. Animal Reproduction Science 138:143-149.
Vasconcelos J L M, Silcox R W, Rosa G J M, Pursley J R and Wiltbank M
C1999 Synchronization rate,size of the ovulatory follicle, and pregnancy rate after synchronization of ovulation beginning on different days of the estrus cycle in lactating dairy cows. Theriogenology 52:1067-1078.
Vijayarajan A and Meenakshisundaram S 2013 Reproductive performance of
anestrus non-descriptive cows treated with CIDR and PGF2α. Indian Journal of Animal Reproduction 34(1).
Waldmann A, Kurykin J, Jaakman U, Kaart T, Aidnik M, Jalakas M, Majas
Land Padrik P 2006 The effects of ovarian function on estrus synchronization with PGF in dairy cows. Theriogenology 66:1364-1374.
Walsh R B, LeBlanc S J, Duffield T D, Kelton D F, Walton J S and Leslie K E2007(a) Synchronization of Estrus and Pregnancy Risk in Anestrous Dairy Cows after treatment with a Progesterone- Releasing Intravaginal Device. Journal of Dairy Science 90:1139-1148.
Whittier W D, Gwazduaskas F C and McGilliard M L 1989 Prostaglandin F2α
usage in a dairy reproduction program for treatment of unobserved estrus, pyometra and ovarian luteal cysts. Theriogenology. 32:693-704.
74
Wolfenson D, Thatcher W W, Savio J D, Bandinga L and Lucy M C 1994 Theeffect of a GnRH analogue on the dynamics of follicular development and synchronization of estrus in lactating dairy cows. Theriogenology 42 : 633-644.
Walsh R B, LeBlanc S J, Duffield T F, Kelton D F, Walton J S and Leslie K
E2007(b) The effect of a progesterone releasing intravaginal device(PRID)on pregnancy risk to fixed-time insemination following diagnosis of non pregnancy in dairy cows. Theriogenology 67:948-956.
Whisnant C S, Washburn S P and Farin P W 2000 Current concepts
insynchronization of estrus and ovulation of dairy cows. American society of Animal sciences.
Xu Z Z and Burton L J 2000 Estrus synchronization of lactating dairy cows
withGnRH, progesterone and prostaglandinF2α. Theriogenology 83:471-476.
Xu, Z Z, Burton L J, McDougall S and Jolly P D 2000 Treatment of
noncycling lactating dairy cows with progesterone and estradiol (or) with progesterone, GnRH, prostaglandinF2α and estradiol. Journal of Dairy Science 83:464-470.
Yildiz A 2010 Effects of administering ovsynch protocol plus post breeding
infusion on service pregnancy outcome in cows. Journal of Animal andVeterinary Advances 9(9):1345-1350.
Zimbelman R G, Lauderdale J W,Solowski J H and Schalk T G 1970 Safety
and pharmacologic evaluations of melengesterolacetate in cattle and other animals. A review. Journal of American Veterinary Medical Association 157 : 152.
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