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Pulsatile secretion of oestradiol-17β in post-partum dairy cows

Published online by Cambridge University Press:  02 September 2010

A. R. Peters  and
B. M. A. O. Perera
A. R. Peters
Affiliation:
AFRC Research Group on Hormones and Farm Animal Reproduction, University of Nottingham, Faculty of Agricultural Science, Sutton Bonington, Loughborough LE12 5RD
B. M. A. O. Perera
Affiliation:
AFRC Research Group on Hormones and Farm Animal Reproduction, University of Nottingham, Faculty of Agricultural Science, Sutton Bonington, Loughborough LE12 5RD
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Abstract

Thirteen dairy cows between 7 and 20 days post partum were fitted with catheters in both the jugular vein and caudal vena cava, the latter with the tips anterior to the junction with the ovarian veins. Blood samples were taken from nine control cows from both sites at 15-min intervals for periods of between 8 and 16 h. Four more cows were sampled for 13 h and given 4 × 2·5 ug GnRH intravenously at 3-h intervals starting 1 h after sampling began. Plasma oestradiol-17(3 concentrations were significantly higher in the vena cava than in the jugular vein in the two cows in which they were compared. Twenty-eight LH pulses occurred in the nine control cows during the sampling periods. These were followed within 1 h by increases in caval oestradiol-17β concentrations in 26 cases. LH pulses occurred after 14 of the 16 GnRH injections and with one exception were associated with oestradiol pulses in the vena cava. Oestradiol concentrations generally peaked 15 to 45 min after each LH peak. It is concluded that ovarian follicles are responsive to LH pulses by releasing oestradiol pulses early in the post-partum period.

Type
Research Article
Information
Animal Production , Volume 49 , Issue 3 , December 1989 , pp. 335 - 338
Copyright
Copyright © British Society of Animal Science 1989

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References

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