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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
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
Copyright
Copyright © British Society of Animal Science 1989

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References

REFERENCES

Baird, D., Swanston, I. and Scaramuzzi, R. J. 1976. Pulsatile release of LH and secretion of ovarian steroids in sheep during the luteal phase of the oestrous cycle. Endocrinology 98: 14901496.CrossRefGoogle Scholar
Bulman, D. C. and Lamming, G. E. 1978. Milk progesterone levels in relation to conception, repeat breeding and factors influencing acyclicity in dairy cows. Journal of Reproduction and Fertility 54: 447458.CrossRefGoogle ScholarPubMed
Foster, J. P., Lamming, G. E. and Peters, A. R. 1980. Short-term relationships between plasma LH, FSH and progesterone concentrations in post-partum dairy cows and the effect of Gn-RH injection. Journal of Reproduction and Fertility 59: 321327.CrossRefGoogle ScholarPubMed
Jagger, J. P., Peters, A. R. and Lamming, G. E. 1987. Hormone responses to low-dose GnRH treatment in post-partum beef cows. Journal of Reproduction and Fertility 80: 263269.CrossRefGoogle ScholarPubMed
Lamming, G. E., Peters, A. R., Riley, G. M. and Fisher, M. W., 1982. Endocrine regulation of post-partum function. In Factors Influencing Fertility in the Postpartum Cow (ed. Karg, H. and Schallenberger, E.), pp. 148172. Martinus Nijhoff, The Hague.Google Scholar
Peters, A. R., Lamming, G. E. and Fisher, M. W. 1981. A comparison of plasma LH concentrations in milked and suckling post-partum cows. Journal of Reproduction and Fertility 62: 567573.CrossRefGoogle ScholarPubMed
Peters, A. R., Pimentel, M. G. and Lamming, G. E. 1985. Hormone responses to exogenous GnRH pulses in post-partum dairy cows. Journal of Reproduction and Fertility 75: 557565.CrossRefGoogle ScholarPubMed
Riley, G. M., Peters, A. R. and Lamming, G. E. 1981. Induction of pulsatile LH release, FSH release and ovulation in post-partum acyclic beef cows by repeated small doses of Gn-RH. Journal of Reproduction and Fertility 63: 559565.CrossRefGoogle ScholarPubMed
Schallenberger, E., Schams, D., Bullermann, B. and Walters, D. L. 1984. Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during prostaglandin-induced regression of the corpus luteum in the cow. Journal of Reproduction of Fertility 71: 493501.CrossRefGoogle ScholarPubMed
Sears, P. M., Paape, M. J., Pearson, R. E. and Gwazdauskas, F. C. 1978. Comparison between tail vein and jugular vein cannulation in cattle. Journal of Dairy Science 61: 974979.CrossRefGoogle ScholarPubMed
Walters, D. L. and Schallenberger, E. 1984. Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during the periovulatory phase of the oestrous cycle in the cow. Journal of Reproduction and Fertility 71: 503512.CrossRefGoogle ScholarPubMed
Walters, D. L., Schams, D. and Schallenberger, E. 1984. Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during the luteal phase of the oestrous cycle in the cow. Journal of Reproduction and Fertility 71: 479491.CrossRefGoogle ScholarPubMed
Webb, R., Lamming, G. E., Haynes, N. B., Hafs, H. D. and Manns, J. G. 1977. Response of cyclic and post-partum suckled cows to injections of synthetic LHRH. Journal of Reproduction and Fertility 50: 203210.CrossRefGoogle Scholar