HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by SAUMANDE, J. Articles by PELLETIER, J. Search for Related Content PubMed PubMed Citation Articles by SAUMANDE, J. Articles by PELLETIER, J.

I.N.R.A., Station de Physiologie de la Reproduction, 37380 Nouzilly, France

(Received 5 July 1974)

Plasma levels of oestradiol-17β (OE) and progesterone are correlated with the ovulation rate of pregnant mare serum gonadotrophin (PMSG)-treated cattle (Henricks & Lamond, 1972; Lemon & Saumande, 1972). No correlation was found however between the size of the preovulatory discharge of luteinizing hormone (LH) and OE secretion or the ovulation rate (Henricks, Hill, Dickey & Lamond, 1973).

To study the relationship between plasma OE and LH concentrations and the ovulation rate of cattle, seven cows and six heifers were treated to produce superovulation by giving 1600 i.u. PMSG on day 16 of the cycle (day 0 = day of oestrus) and 1500 i.u. human chorionic gonadotrophin (HCG) at the onset of the next oestrus [used to induce multiple pregnancies in our laboratory (Mauleon, Mariana, Benoit, Solari & Chupin, 1970)]. Blood was collected by acute puncture of