caa a22 4500 38632106X CHVBK 20180307111627.0 cr unu---uuuuu 161130e198804 xx s 000 0 eng 10.1017/S0003356100042215 doi S0003356100042215 pii (NATIONALLICENCE)cambridge-10.1017/S0003356100042215 Endocrine response to superovulatory treatment in pre-pubertal beef heifers: its lack of ability to induce puberty [Elektronische Daten] This study was carried out to investigate: (1) changes in plasma oestradiol-17β and progesterone concentrations in six pre-pubertal beef heifers, 9 months old, subjected to a superovulatory treatment, consisting of a single dose of PMSG followed 120 h later by a single injection of human chorionic gonadotrophin (HCG); and (2) the ability of this treatment to trigger cyclic gonadal activity. After PMSG administration, oestradiol-17β levels increased from 11·8 (s.d. 10·78) to 92·9 (s.d. 38·15) ng/1 just before HCG injection. The oestradiol-17β increase during the superovulatory treatment and numbe r of ovulations were correlated (r = 0·83; P < 0·05). After HCG injection, progesterone concentrations rose significantly reaching values which in some cases were higher than 60 [μg/1. The progesterone peak on days 9 and 10 post HCG was strongly correlated with the number of corpora lutea (r = 0·95; P < 0·01 and r = 0·92; P < 0·01, respectively). Progesterone determinations were performed for a period of 90 days after HCG administration. No evidence was found for the induction of permanent cyclic ovarian activity since all heifers returned, after the induced luteal phase, to their pre-pubertal condition. Copyright © British Society of Animal Science 1988 Bonavera J. J. Department of Animal Production, School of Agricultural Sciences, University of Mar del Plata, CC 276 (7620) Balcarce, Argentina Tortonese D. J. Department of Animal Production, School of Agricultural Sciences, University of Mar del Plata, CC 276 (7620) Balcarce, Argentina Doray J. M. Department of Animal Production, School of Agricultural Sciences, University of Mar del Plata, CC 276 (7620) Balcarce, Argentina Petraglia F. Department of Animal Production, School of Agricultural Sciences, University of Mar del Plata, CC 276 (7620) Balcarce, Argentina Animal Production Cambridge University Press 46/2(1988-04), 163-167 0003-3561 46:2<163 1988 46 ASC https://doi.org/10.1017/S0003356100042215 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0003356100042215 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bonavera J. J. Department of Animal Production, School of Agricultural Sciences, University of Mar del Plata, CC 276 (7620) Balcarce, Argentina NATIONALLICENCE 700 1- Tortonese D. J. Department of Animal Production, School of Agricultural Sciences, University of Mar del Plata, CC 276 (7620) Balcarce, Argentina NATIONALLICENCE 700 1- Doray J. M. Department of Animal Production, School of Agricultural Sciences, University of Mar del Plata, CC 276 (7620) Balcarce, Argentina NATIONALLICENCE 700 1- Petraglia F. Department of Animal Production, School of Agricultural Sciences, University of Mar del Plata, CC 276 (7620) Balcarce, Argentina NATIONALLICENCE 773 0- Animal Production Cambridge University Press 46/2(1988-04), 163-167 0003-3561 46:2<163 1988 46 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge