Primjena GnRH i PGF za indukciju estrusa i sinkronizaciju ovulacije u mliječnih krava

master's thesis

• Title (english): Application of GnRH and PGF for Estrus Induction and Synchronization of Ovulation in Dairy Cows
• Author: Patrik Meglić
• Mentor: Branimira Špoljarić (mentor)
• Mentor: Silvijo Vince (mentor)
• Committee member: Ivan Folnožić (predsjednik povjerenstva)
• Committee member: Branimira Špoljarić (član povjerenstva)
• Committee member: Silvijo Vince (član povjerenstva)
• Granter: University of Zagreb; Faculty of Veterinary Medicine; (Reproduction and Obstetrics Clinic); Zagreb
• Defense date and country: 2020-07-10, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Veterinary Medicine; Veterinary Clinical Sciences

Abstract

Uzgajivači mliječnih goveda u svojim krdima redovito koriste postupak umjetnog osjemenjivanja. U današnje se vrijeme tradicionalna metoda detekcije estrusa promatranjem pokazala vremenski vrlo neučinkovitom zato što se javlja tendencija za povećanjem broja životinja u stadu, kod krava se sve češće javlja tiho gonjenje ili znakovi estrusa budu slabo izraženi. Kako bi se smanjila potreba za vizualnom detekcijom estrusa sve se češće koriste hormonalni protokoli koji omogućavaju sinkronizaciju velikog broja životinja i vremenski tempirano umjetno osjemenjivanje. Najčešći korišteni hormonalni protokol koji koristi GnRH i PGF2α naziva se Ovsynch. U tom se protokolu u bilo kojoj fazi ciklusa aplicira GnRH, sedam dana nakon toga slijedi aplikacija PGF2α, dva dana kasnije druga aplikacija GnRH te vremenski tempirano umjetno osjemenjivanje uslijedi 8-24 sata nakon posljednje aplikacije GnRH. Nedostatak ovog protokola je taj što životinje različito mogu odgovoriti na hormonalni tretman. Tako na primjer Ovsynch protokol pokazuje lošije rezultate kod junica i kod krava s tri folikularna vala. Ovom se problemu pokušava doskočiti različitim modifikacijama originalnog Ovsynch protokola. Tako je na primjer razvijen Double Ovsynch protokol koji pokazuje bolje rezultate kod junica ili Ovsynch protokol uz suplementaciju progesterona koji se češće koristi kod anestričnih krava ili krava s cističnim jajnicima. Kako bi se povećala stopa sinkronizacije unutar stada koriste se presinkronizacijski protokoli koji zbog duljeg trajanja homogenije sinkroniziraju stado. Resinkronizacijski protokoli koriste se kod krava koje nisu postale gravidne nakon prethodnog osjemenjivanja. Takvi protokoli omogućavaju brzo ponovno osjemenjivanje negravidnih krava. Nadalje, primjena navedenih hormona uspješno se koristi i u liječenju određenih stanja neplodnosti u mliječnih krava.

Abstract (english)

Dairy cattle breeders regularly use the process of artificial insemination in their herds. Nowadays, the process of visual heat detection has proven to be very time consuming because there is tendency to increase the number of animals in herds. Furthermore, silent estrus is more often observed and sings of estrus are becoming weaker. In order to reduce the need for visual detection of estrus, hormonal protocols are increasingly used, which enable the synchronization of a large number of animals and timed artificial insemination. Most commonly used hormonal protocol that uses GnRH and PGF2α is called Ovsynch. In this protocol, GnRH is applied at any stage of the cycle, followed by PGF2α application seven days after, and another GnRH application two days after the application of second GnRH. Timed artificial insemination is preformed 8-24 hours after the second GnRH application. The disadvantage of this protocol is that animals respond differently to hormonal treatment. Thus, for example, the Ovsynch protocol shows poorer results in heifers and in cows with cycles with three follicular waves. Various modifications of the original Ovsynch protocol are attempted to resolve this problem. For example, the Double Ovsynch protocol was developed, which shows better results in heifers. Another modification is supplementation of Ovsynch protocol with progesterone, which is more commonly used in anestric cows or cows with cystic ovaries. In order to increase the synchronization rate within the herd, presynchronization protocols are used, which, due to their longer duration, synchronize the heard more homogeneously. Resynchronization protocols are used in cows that have not become pregnant after previous insemination. Such protocols allow rapid reinsemination of non-pregnant cows. Furthermore, these hormons are effective in treatment of some fertility-related problems in dairy cows.

• Keywords: mliječne krave; GnRH; PGF; Ovsynch; neplodnost
• Keywords (english): dairy cow; GnRH; PGF; Ovsynch; infertility
• Language: croatian
• URN:NBN: urn:nbn:hr:178:570644
• Study programme: Title: Veterinary Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica veterinarske medicine (doktor/doktorica veterinarske medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-12-09 17:39:59