FU Berlin Digitale Dissertation
Swantje Kuchenbuch : Reproductive management in dairy heifers: Comparison of timed artificial insemination and insemination on observed estrus Fruchtbarkeitsmanagement bei Färsen durch Brunstsynchronisation: Vergleich von terminierter Doppelbesamung mit der Besamung nach Brunstanzeichen
|Abstract| |Table of Contents| |More Information|

Abstract This study was conducted to improve reproductive efficiency and to increase the knowledge of follicular dynamics after synchronization of estrus with GnRH and Prostaglandin F2 in dairy heifers. Three experiments were carried out on a confinement housing heifer raising unit in Brandenburg. Each experiment compared reproductive management protocols based on synchronization of estrus by means of treating heifers with GnRH (Fertagyl Intervet) 7 days apart. The control group of all experiments was watched for signs of estrus during 5 days after the administration of PGF2. In experiment 1 this procedure (Group 1a) was compared to two timed artificial inseminations (TAI) carried out 72 and 96 hours after the application of PGF2(Group 2). In experiment 2 Group 1b was compared to a group inseminated twice at 72 and 104 hours after treatment with PGF2(Group 3). In experiment 3, Group 1c was compared to Group 4. Heifers in Group 4 were inseminated twice at 72 and 96 hours after treatment with PGF2 but received a second dose of GnRH at the first insemination. Follicular dynamics were observed by ultrasound during a period between 48 and 104 hours after PGF2 in all groups. Examinations were carried out twice daily in the morning and in the afternoon on three consecutive days. The diameter of large follicles was documented in a spreadsheet. An ovulation was characterized by the disappearance of a large diameter follicle, that had been observed during the previous examination. In experiment 1 conception rates did not differ between the two groups (46.9 % vs. 53.6 %, p>0.05). However, as all heifers in Group 2 were inseminated, pregnancy rates on induced estrus were higher in Group 2 (40.6 % vs. 53.6 %, p<0.05). Insemination of heifers returning to estrus in Group 1a compensated for this (Conception rate: 88,2%), so that the number of pregnancies per time interval was significantly higher in Group 1a than in Group 2.

Table of Contents Download the whole PhDthesis as a zip-tar file or as zip-File For download in PDF format click the chapter title Titelblatt,Gutachter,Abkürzungsverzeichnis,Inhaltsverzeichnis, Lebenslauf,Selbstständigkeitserklärung, Danksagung 1.Einleitung 2.Literaturübersicht 3. Material und Methode 4. Ergebnisse 5. Diskussion 6. Zusammenfassung 7. Summary Literaturverzeichnis

More Information:
Online available:	http://www.diss.fu-berlin.de/2001/97/indexe.html
Language of PhDThesis:	german
Keywords:	Heifers;Estrus;Synchronization;Reproduction;Management
DNB-Sachgruppe:	34 Veterinärmedizin
Date of disputation:	09-Feb-2001
PhDThesis from:	Fachbereich Veterinärmedizin, Freie Universität Berlin
First Referee:	Univ. -Prof. Dr. W. Heuwieser
Second Referee:	Univ.- Prof. Dr. R. Mansfeld
Third Referee:	Univ.- Prof. Dr. Zessin
Contact (Advisor):	swantje@eule.de
Date created:	20-Dec-2001
Date available:	17-Jan-2002

 

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