Fecha/hora: 15/06/2024 21:18:52

Biblioteca(s): 	INIA Tacuarembó.	
Fecha corriente: 	15/05/2015	
Fecha de la última actualización: 	03/02/2020	
Autoria: 	VIÑOLES, C.; FORSBERG, M.; BANCHERO, G.; RUBIANES, E.	
Afiliación: 	CAROLINA VIÑOLES GIL, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; Centre for Reproductive Biology, Department of Clinical Chemistry, Swedish University of Agricultural Sciences, Uppsala, Swed;Universidad de la República (UdelaR)/ Facultad de Veterinaria; M. FORSBERG, Centre for Reproductive Biology, Department of Clinical Chemistry, Swedish University of Agricultural Sciences, Uppsala, Swed; GEORGGET ELIZABETH BANCHERO HUNZIKER, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; E. RUBIANES, Universidad de la República (UdelaR)/ Facultad de Veterinaria.	
Título: 	Ovarian follicular dynamics and endocrine profiles in Polwarth ewes with high and low body condition.	
Año de publicación: 	2002	
Fuente/Imprenta: 	Animal Science, 2002, v. 74, no. 3, p. 539-545.	
DOI: 	10.1017/S1357729800052693	
Idioma: 	Inglés	
Notas: 	Article history: Received 20 July 2001 // Accepted 14 November 2001 // Published online by Cambridge University Press: 18 August 2016.	
Contenido: 	In this investigation we tested the hypothesis that static body condition (BC) of the ewe affects oestradiol and FSH with implications for subsequent follicular growth and turn-over. Sixteen Polwarth ewes were selected from a flock according to their BC score (scale: 1 emaciated; 5 obese). High BC (HBC) ewes (no. = 8) had a BC score of 4.1 (s.e. 0.1) and low BC (LBC) ewes (no. = 8) had a BC score of 1.9 (s.e. 0.1). Daily ultrasound examinations were performed and blood samples for progesterone, oestradiol and follicle-stimulating hormone (FSH) determination were collected. All HBC ewes (8/8) exhibited three waves of follicular development, while four LBC ewes (418) had two waves and the other four (4/8) had three waves of follicular development (P less than or equal to0.05) during the interovulatory period. Overall, the emergences of 33 out of 44 follicular waves were preceded by significant increases in FSH concentrations. Maximum FSH concentrations were detected 0.9 +/- 0.2 days before wave emergence. Oestradiol concentrations increased significantly during the growing phase in 38 out of 44 large follicles. A negative correlation between oestradiol and FSH was observed in HBC ewes. A similar inhibitory effect of oestradiol on FSH was observed in LBC ewes, irrespective of whether they developed two or three follicular waves. However, a longer period with high FSH was needed to promote the emergence of the second follicular wave in two-wave LBC ewes. Four HBC ewes had twin ovulations but no LBC ewes did (P less than or equal to 0.05). In HBC ewes, the follicular phase was characterized by lower oestradiol (6.5 (s.e. 1.0) pmol/l) but higher mean FSH concentrations (2.4 (s.e. 0.4) mug/l) than in LBC ewes (8.9 (s.e. 1.2) pmol/l and 2.0 (s.e. 0.3) mug/l, respectively, P less than or equal to 0.05). The present results suggest that BC influences the pattern of follicular dynamics through changes in the endocrine milieu. Higher FSH concentrations during the follicular phase in HBC ewes, which allowed an extended period of follicular recruitment from a significantly larger pool of small antral follicles could explain the higher ovulation rate observed in this group.	
Palabras-Clave: 	CONFORMATION; EWES; FOLLICLES; FSH; OESTRADIOL.	
Thesagro: 	MEDICINA VETERINARIA.	
Categoría del tema: 	L53 Fisiología Animal - Reproducción	
Registro original: 	INIA Tacuarembó (TBO)	
Ejemplares: 	TBO - (100648-1) - PXI - AP - PP - PP/ANIMAL SCIENCE/2002 -  -  - DIS