Ovarian dynamics in response to two modified intravaginal progesterone releasing device and oestradiol benzoate based ovulation synchronisation protocols designed for use in Brahman heifers

Edwards, S. A. A., Atkinson, P. C., Satake, N., Boe-Hansen, G. and McGowan, M. R. (2014) Ovarian dynamics in response to two modified intravaginal progesterone releasing device and oestradiol benzoate based ovulation synchronisation protocols designed for use in Brahman heifers. Animal Reproduction Science, 148 1-2: 18-25. doi:10.1016/j.anireprosci.2014.05.005


Author Edwards, S. A. A.
Atkinson, P. C.
Satake, N.
Boe-Hansen, G.
McGowan, M. R.
Title Ovarian dynamics in response to two modified intravaginal progesterone releasing device and oestradiol benzoate based ovulation synchronisation protocols designed for use in Brahman heifers
Journal name Animal Reproduction Science   Check publisher's open access policy
ISSN 0378-4320
1873-2232
Publication date 2014-07
Year available 2014
Sub-type Article (original research)
DOI 10.1016/j.anireprosci.2014.05.005
Open Access Status
Volume 148
Issue 1-2
Start page 18
End page 25
Total pages 8
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2015
Language eng
Formatted abstract
The objective was to investigate the ovarian response of Brahman heifers to two modified ovulation synchronisation protocols developed to increase the proportion of normal synchronous ovulations. Experiment 1 characterised the growth of the ovulatory follicle in heifers (n = 19) treated with an intravaginal progesterone releasing device (IPRD) and oestradiol benzoate (ODB), to determine the optimal time to induce ovulation. Using the findings from Experiment 1, Experiment 2 investigated the effect of reducing the duration of IPRD insertion and increasing the interval from IPRD removal to ODB treatment (modified protocol 1 – OPO-6; n = 20), and omitting ODB treatment at the time of IPRD insertion (modified protocol 2 – PO-6; n = 20). An IPRD (0.78 g progesterone) was inserted at Day 0 (OPO-8) or Day 2 (OPO-6 and PO-6) and all heifers also received 1 mg ODB i.m. Day 8: IPRD removed + 500 μg cloprostenol i.m. At 24 h (OPO-8) and 36 h (OPO-6 and PO-6) post IPRD removal: 1 mg ODB i.m. Fixed-time AI (FTAI) occurred at 54 h for OPO-8 and 72 h for OPO-6 and PO-6, post IPRD removal. After IPRD treatment all OPO-6 and OPO-8 heifers initiated a new follicular wave whereas 25% of PO-6 heifers failed. Diameter of the dominant follicle was larger at FTAI in the PO-6 (11.34 ± 0.50 mm) compared to the OPO-8 protocol (9.74 ± 0.51 mm; P < 0.05), but similar to the OPO-6 protocol (10.52 ± 0.51 mm). Proportion of ovulations occurring 12 h prior and 24 h post FTAI was similar for the PO-6 (80%) and OPO-6 (75%) protocols but numerically lower in the OPO-8 heifers (60%). The apparent improvement in ovarian response in heifers treated with the modified protocols needs to be confirmed in larger field studies.
Keyword Bos indicus
Brahman
Progesterone
Fixed-time artificial insemination
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Veterinary Science Publications
 
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Created: Tue, 15 Jul 2014, 17:58:21 EST by Dr Sophia Edwards on behalf of School of Veterinary Science