| Abstract | Cilj kontroliranog rasplođivanja je poboljšanje plodnosti. Današnja razina razumijevanja
folikularne dinamike rezultirala je razvojem sustava kontroliranog rasplođivanja s fiksnim
vremenom osjemenjivanja i resinkronizacijom plotkinja koje nisu koncipirale, uz pomoć
farmakoloških metoda indukcije folikulogeneze, luteolize i luteogeneze te ranom ultrazvučnom
dijagnostikom graviditeta. Ovsynch protokol je rutina u poslijeporodnom rasplođivanju te
programu resinkronizacije koji se koriste za poboljšanje učinkovitosti i skraćenje trajanja
ponovnih inseminacija. Kako se najveći postotak koncepcije postigne ako se s protokolom
započne sredinom ciklusa, najbolji način za postizanje tog cilja jest primjena
presinkronizacijkih protokola koji prethode Ovsynchu, a za bolju sinkronizaciju faza ciklusa.
Istraživanjem je bilo obuhvaćeno 60 visokomliječnih krava podijeljenih u tri jednake skupine.
Prva skupina je primila presinkronizaciju sa GnRH i PGF 9 i 2 dana prije početka Ovsyncha,
druga samo PGF 2 dana prije Ovsyncha, a treća skupina je bila kontrolna i primila je samo
Ovsynch. 23 dana po UO sve krave su primile GnRH a sedam dana kasnije su ultrazvukom
pregledane na gravidnost. Plotkinjama koje nisu koncipirale je nastavljena resinkronizacija
Ovsynchom. Postotak koncepcije se značajno razlikovao u fazi sinkronizacije, i krave koje nisu
bile presinkronizirane su imale najslabiju koncepciju. U fazi resinkronizacije sve tri grupe su
imale podjednaku stopu gravidnosti. Nesumnjivo je da protokoli koji se baziraju na Ovsynchu
predstavljaju velik korak u shvaćanju i korištenju reprodukcije. Njihov cilj je kontrola rasta,
funkcije i trajanja dominantnog folikula kako bi se poboljšala plodnost. U konačnici, dolazi i
do poboljšanja mliječnosti, smanjenja stopa pobola i izlučenja i stvaranja dovoljnog broja
zamjenskih junica. |
| Abstract (english) | Aim: The aim of controled reproduction is enhanced fertility. Knowledge of the factors and
mechanisms involved in folliculogenesis and luteogenesis has resulted in development of
controled reproduction system with timed artificial insemination, resynchronization of cows
that did not concieve at first AI, and strategies for better embryo survival rate. This is achieved
through pharmacologicaly induced methods of folliculogenesis, luteolysis and luteogenesis
and resynchronization in due time, with the main goal of enhancing fertility and preventing
subfertility. Ovsynch is a routine procedure in postpartal insemination programs and in
resynchronization programs, which are used to shorten the period between inseminations. Since
the middluteal phase of oestrous cycle is desired time to start the protocol, the best way to
achieve this is to apply presynchronization protocols. This induction protocols precede
Ovsynch, and thanks to them, better cycle synchronization is achieved.
Methodology: The research was conduceted on one dairy farm in Croatia, on 60 cows
divided in three equal groups, each comprised of 20 animals. The first group A was
presynchronized with GnRh and PGF nine and two days before startin Ovsynch. The second
group B was presynchronized with just one application of PGF two days before Ovsynch. The
third group C served as control, and was not subjected to presynchronization. All cows were
artificially inseminated at fixed time. 23 days after TAI, GnRH was applied to all cows, as a
start of Ovsynch in resynchronization. Seven days later, all cows were checked on pregnancy
with ultrasound. Those diagnosed as non-pregnant continued with Ovsynch and TAI. Blood
samples were collected for analysis of hormones (progesteron, estradiol, luteinizing hormone)
and several metabolic parameters (urea, creatinin, cholesterol, total protein, glucosis, ALT,
AST, GGT). Also, body condition score, parity and lactation was analysed for all cows.
Results: The results indicate that cows recieving presynchronisation had better pregnancy
rate comparedAim: The aim of controled reproduction is enhanced fertility. Knowledge of the factors and
mechanisms involved in folliculogenesis and luteogenesis has resulted in development of
controled reproduction system with timed artificial insemination, resynchronization of cows
that did not concieve at first AI, and strategies for better embryo survival rate. This is achieved
through pharmacologicaly induced methods of folliculogenesis, luteolysis and luteogenesis
and resynchronization in due time, with the main goal of enhancing fertility and preventing
subfertility. Ovsynch is a routine procedure in postpartal insemination programs and in
resynchronization programs, which are used to shorten the period between inseminations. Since
the middluteal phase of oestrous cycle is desired time to start the protocol, the best way to
achieve this is to apply presynchronization protocols. This induction protocols precede
Ovsynch, and thanks to them, better cycle synchronization is achieved.
Methodology: The research was conduceted on one dairy farm in Croatia, on 60 cows
divided in three equal groups, each comprised of 20 animals. The first group A was
presynchronized with GnRh and PGF nine and two days before startin Ovsynch. The second
group B was presynchronized with just one application of PGF two days before Ovsynch. The
third group C served as control, and was not subjected to presynchronization. All cows were
artificially inseminated at fixed time. 23 days after TAI, GnRH was applied to all cows, as a
start of Ovsynch in resynchronization. Seven days later, all cows were checked on pregnancy
with ultrasound. Those diagnosed as non-pregnant continued with Ovsynch and TAI. Blood
samples were collected for analysis of hormones (progesteron, estradiol, luteinizing hormone)
and several metabolic parameters (urea, creatinin, cholesterol, total protein, glucosis, ALT,
AST, GGT). Also, body condition score, parity and lactation was analysed for all cows.
Results: The results indicate that cows recieving presynchronisation had better pregnancy
rate compared to cows that recieved Ovsynch only (A 29,41 %, B 47,37 % and C 21,05 %). In
resynchronization, conception rate did not differ among groups, and was around 30 %.
However, BCS, parity and lactation did not have any effect on pregnancy rate. Analysis of
luteinizing hormone showed that all cows had ovulated. Progesteron concentration differed
significantly between group C and groups A and B (p<0,001) on the start of Ovsynch in
synchronization, thus indicating that combined protocols are more effective due to better
homogenization of folliculogenesis and synchronization of ovulation.
Conclusion: There is no doubt that the protocols that are based on Ovsynch (simple, and
modified, but combined) represent a major step in understanding and managing the
reproduction. The philosophy of this aspect is controlled induction of a new follicular wave and
induction of ovulation synchronization. This is only a phase of research, one of which goals is
a control of growth, function and duration of the dominant follicle, all in order to enhance
fertility. Finally that would enhance milk production, reduce the morbidity and culling rate,
and create a sufficient number of replacement heifers. Both of these two combined synchronization protocols used in this research are original, and they have not been previously
used on dairy cow farms. Therefore, they are not found in up-to date literature. Due to good
results, their application should be furtherly evaluated. |
