Fecha/hora: 03/06/2024 04:12:11

Biblioteca(s): 	INIA Treinta y Tres.	
Tipo de la producción científica: 	Artículos en Revistas Indexadas Internacionales	
Circulación/Nivel: 	A - 2	
Fecha corriente: 	19/05/2016	
Fecha de la última actualización: 	15/10/2019	
Autoria: 	MITCHELL, L.M.; RAMILLA, M.J.; QUINTANS, G.; KING, M.E.; GEBBIE, F.E.; ROBINSON, J.J.	
Afiliación: 	SAC, Animal Biology Division, Craibstone, Estate, Bucksburn, Aberdeen.; SAC, Animal Biology Division, Craibstone, Estate, Bucksburn, Aberdeen.; GRACIELA QUINTANS ILARIA, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay. SAC, Animal Biology Division, Craibstone, Estate, Bucksburn, Aberdeen.; SAC, Animal Biology Division, Craibstone, Estate, Bucksburn, Aberdeen.; SAC, Animal Biology Division, Craibstone, Estate, Bucksburn, Aberdeen.; SAC, Animal Biology Division, Craibstone, Estate, Bucksburn, Aberdeen.	
Título: 	Effect of diet and GnRH administration on post-pastum ovarian cyclicity in autumn-lambing ewes.	
Año de publicación: 	2003	
Fuente/Imprenta: 	Animal Reproduction Science, 2003, v. 76, p. 67-79.	
DOI: 	10.1016/S0378-4320(02)00239-7	
Idioma: 	Inglés	
Notas: 	Article history: Received 1 May 2002 // received in revised form 22 October 2002 // accepted 8 November 2002.
Doi: https://doi.org/10.1016/S0378-4320(02)00239-7	
Contenido: 	Abstract:
Using autumn-lambing ewes, this study investigated (i) the effects of diet on gonadotrophin secretion and responsiveness of the hypothalamic-pituitary-ovarian axis to exogenous GnRH during the early post-partum period; and (ii) whether ovulation prior to completion of uterine involution results in an increased incidence of aberrant ovarian cycles. Thirty-two ewes rearing 1.9±0.12 lambs were equally allocated to two dietary treatments at lambing (22 October ±0.2 day). Diets comprised ad libitum hay and 1.5 kg per ewe per day of one of two concentrates (11.5 MJ ME, 195 g CP per kg) containing 300 g kg?1 cracked maize grain (M) or 300 g kg?1 sugar beet pellets (S). Half of the ewes on each diet (G) received 25 i.v. injections of 250 ng GnRH in 2 ml 0.9% saline at 2 h intervals from days 12–14 post-partum while remaining ewes (N) were monitored for the resumption of spontaneous ovarian cyclicity. Blood samples were obtained from all ewes throughout the study (lambing to 18 December) for measurement of circulating hormone concentrations and the uteri and ovaries of all ewes were examined via laparoscopy on day 21 post-partum. There were no effects of dietary treatment on ewe daily live weight loss, lamb daily live weight gain or the immediate post-partum increase in circulating FSH concentrations. Diet did not affect insulin concentrations or LH pulse frequency on day 12 post-partum but LH pulse amplitude was lower in ewes fed concentrate M compared to concentrate S (1.4±0.10 versus 1.7±0.12 ng ml?1, respectively, P<0.05) and this was associated with an increased interval to the resumption of spontaneous ovarian cycles (35±3.1 versus 26±2.1 day, respectively, P<0.05). Administration of exogenous GnRH increased (P<0.05) the proportion of ewes on both diets that ovulated within 20 days of parturition and advanced the onset of ovarian cyclicity in ewes fed concentrate M by 9.5 days (significance of interaction, P<0.05). Four ewes, all of which ovulated before day 22 post-partum, had extended luteal activity while in remaining ewes, duration of the first luteal phase was inversely related to the time of first ovulation (r2=0.16, P<0.05). Results demonstrate that (i) the onset of ovarian cyclicity is influenced by diet and can be advanced by administration of exogenous GnRH; and (ii) ovulation during the early post-partum period is associated with an increased incidence of extended luteal activity.	
Thesagro: 	ALIMENTACION ANIMAL; CICLO ESTRAL; DIETA; OVEJA; REPRODUCCION ANIMAL.	
Categoría del tema: 	--	
URL: 	http://www.ainfo.inia.uy/digital/bitstream/item/5724/1/Quintans-arb-2003-1.pdf	
Registro original: 	INIA Treinta y Tres (TT)	
Ejemplares: 	TT - (101359-1) - PXI - AP - DD - PP/ANIMAL-REPROD.SCIENCE/2003/QUINTANS/1 -  -  - DIS