Use of vaginal electrical resistance to diagnose oestrus, dioestrus and early pregnancy in synchronized tropically adapted beef heifers

Hockey, C. D., Norman, S. T., Morton, J. M., Boothby, D., Phillips, N. J. and McGowan, M. R. (2010) Use of vaginal electrical resistance to diagnose oestrus, dioestrus and early pregnancy in synchronized tropically adapted beef heifers. Reproduction In Domestic Animals, 45 4: 629-636. doi:10.1111/j.1439-0531.2008.01320.x


Author Hockey, C. D.
Norman, S. T.
Morton, J. M.
Boothby, D.
Phillips, N. J.
McGowan, M. R.
Title Use of vaginal electrical resistance to diagnose oestrus, dioestrus and early pregnancy in synchronized tropically adapted beef heifers
Journal name Reproduction In Domestic Animals   Check publisher's open access policy
ISSN 0936-6768
1439-0531
0940-5496
Publication date 2010-08-01
Year available 2009
Sub-type Article (original research)
DOI 10.1111/j.1439-0531.2008.01320.x
Volume 45
Issue 4
Start page 629
End page 636
Total pages 8
Place of publication Berlin, Germany
Publisher Wiley-Blackwell Verlag GmbH
Language eng
Formatted abstract
The primary objective of this study was to determine whether a single measurement of intravaginal electrical resistance (VER), using the commercially available Ovatec® probe, can discriminate between dioestrus and oestrus in Bos indicus females, which had been treated to synchronize oestrus. Santa Gertrudis heifers (n = 226) received one of three oestrous synchronization treatments: double PGF2α 10 days apart, 8-day controlled internal drug release (CIDR) treatment or CIDR pre-synchronization + PGF2α 10 days after CIDR removal. The heifers were inseminated within 12 h following observed oestrus, or, if not observed, at a fixed time approximately 80 h, following the last synchronization treatment. They were palpated per rectum for signs of pregnancy 9 weeks after artificial insemination (AI). Vaginal electrical resistance measurements were taken at the completion of synchronization treatments (presumed dioestrus), immediately prior to AI (oestrus), and then at 3 and 9 weeks post-AI. Mean VER differed between presumed dioestrus and oestrus (113.7 vs 87.4, p < 0.001). The area under the receiver operating characteristics (ROC) curve was 0.925, indicating that VER was highly discriminatory between dioestrus and oestrus. Vaginal electrical resistance at time of AI was negatively associated with odds of conception when all inseminations were included in the analyses [odds ratio (OR) = 0.97; 95% CI 0.95-1.00; p = 0.018], but not when fixed time AIs were excluded (OR = 1.00; 95% CI 0.97-1.03; p = 0.982). Mean VER readings differed between pregnant and non-pregnant animals at both 3 weeks (120.5 vs 96.7, p < 0.001) and 9 weeks (124.0 vs 100.3, p < 0.001) post-AI. However, 3- and 9-week VER measurements were not highly discriminatory between pregnancy and non-pregnancy (area under ROC curve = 0.791 and 0.736, respectively). Mean VER at time of AI for animals diagnosed in oestrus differed between each of the oestrous synchronization treatments (84.7, 73.6 and 78.9, groups 1-3 respectively, p < 0.001). These findings suggest that measurement of VER may improve accuracy of oestrus diagnoses when selecting cattle for AI following oestrous synchronization programmes involving tropically adapted cattle. © 2009 The Authors. Journal compilation © 2009 Blackwell Verlag.
Keyword Electronic proble measurements
Dairy-cows
Milk progesterone
Reproductive management
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Available online: 9 JAN 2009

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Veterinary Science Publications
 
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Created: Sun, 01 Aug 2010, 10:01:01 EST