RT Journal Article
T1 Amplitude of the plasma melatonin nycthemeral rhythms is not associated with the dates of onset and offset of the seasonal ovulatory activity in the Ile-de-France ewe
A1 Zarazaga Garcés, Luis Ángel
A1 Malpaux, Benoît
A1 Chemineau, Phileppe
AB We investigated if absolute (nocturnal) or relative (nocturnal/diurnal ratio) plasmamelatonin concentrations were associated with the seasonal ovulatory activity in Ile-de-Franceewes. Ninety-six and 121 ewes in two different groups of the same flock were used to determine thepotential existence of a relationship between melatonin concentrations at the summer and winter solstices,and the dates of onset and offset of the ovulatory activity, respectively. The dates of the firstand last ovulations were estimated by assaying progesterone in plasma samples taken once weekly.Mean ± SEM (1) plasma melatonin concentrations at the summer solstice and at the winter solsticewere 302.4 ± 19.4 and 412.0 ± 18.7 pg·mL–1, respectively, (2) date of onset of the breeding season29 Jul. ± 1.6 days, (3) date of offset of the breeding season 24 Jan. ± 2.2 days. In spite of a large variabilityin the different traits studied here, the analyses of correlation and regression indicated thatneither the absolute nor relativemelatonin concentrations were significantly relatedwith the dates ofonset or offset of ovulatory activity. Therefore, we concluded that absolute or relative plasmamelatonin concentrations are not linked to the seasonal breeding activity, in Ile-de-France ewes.
PB Institut National de la Recherche Agronomique (INRA)
SN 0926-5287
SN 1297-9708 (online)
YR 2003
FD 2003
LK http://hdl.handle.net/10272/6392
UL http://hdl.handle.net/10272/6392
LA eng
NO Zarazaga Garcés, L.A., Malpaux, B., Chemineau, P.: "Amplitude of the plasma melatonin nycthemeral rhythms is not associated with the dates of onset and offset of the seasonal ovulatory activity in the Ile-de-France ewe". Reproduction Nutrition Development. Vol. 43, pág. 167-177 (2003). ISSN 0926-5287
DS Repositorio Institucional de la Universidad de Huelva
RD 1 jun 2026