Fecha/hora: 08/06/2024 22:59:58

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: 	11/10/2019	
Autoria: 	SINCLAIR, K.D.; MOLLE, G.; REVILLA, R.; ROCHE, J.F.; QUINTANS, G.; MORONGIU, L.; SANZ, A.; MACKEY, D.R.; DISKIN, M.G.	
Afiliación: 	Stottish Agricultural College, Aberdeen.; Instituto Zootecnico e Caseaario per la Sardegna, Olmedo, Sardinia, Italy; Servicio de Investigación Agraria, Unidad de Producicón Animal, Zaragoza, Spain; Faculty Veterinary Medicine, Univerity college Dublin, Ireland.; GRACIELA QUINTANS ILARIA, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay. Scottish Agricultural College, Aberdeen; Instituto Zootecnico e Caseario per la Sardegna, Olmedo, Sardinia, Italy; Servicio de Investigación Agraria, Unidad de Producción Animal, Zaragoza, Spain; Faculty Veterinary Medicine, University College Dublin, Ireland. Teagasc, Athenry, Co. Galway, Ireland.; Teagasc, Athenry, Co. Galway, Ireland.	
Título: 	Ovulation of the first dominant follicle arising after day 21 post partum in suckling beef cows.	
Año de publicación: 	2002	
Fuente/Imprenta: 	Animal Science, 2002, v. 75, p. 115-126.	
DOI: 	10.1017/S1357729800052899	
Idioma: 	Inglés	
Notas: 	Article history: Received 8 December 2001 // Accepted 11 February 2002 // Published online 18 August 2016.
DOI: https://doi.org/10.1017/S1357729800052899	
Contenido: 	The effects of body condition score (BCS) of 2·0 or 3·0 units at calving (low v. moderate), post-partum energy intake at 0·6 or 1·0 MJ metabolizable energy (ME) per day per kg M0·75 (low v. high) and unrestricted or restricted (once daily) suckling on the ability of cows to ovulate were studied in a 2 ? 2 ? 2 factorial design with each treatment replicated eight times. Calf isolation and restricted suckling were imposed shortly after selection of the first dominant follicle (DF) to emerge after day 21 post partum. The episodic release of LH (sampled at 15-min intervals for 10 h) was determined 48 h before and 48 h after the day calf isolation and restricted suckling commenced. Additional blood samples were collected weekly for plasma insulin determination. The mean interval from calving to first ovulation was shorter for cows in moderate than low BCS at calving (47·8 v. 57·1 days, s.e.d. = 4·50, P < 0·05), and for cows suckling once daily than for those with unrestricted suckling (42·9 v. 62·0 days, s.e.d. = 4·50, P < 0·001). Post-partum nutrition did not affect this interval. Mean LH pulse frequency prior to the start of restricted suckling was higher for cows of moderate than low BCS at calving (3·2 v. 1·6 pulses per 10 h, s.e.d. = 0·60, P < 0·05). Subsequently, LH pulse frequency was higher for cows suckling once daily than for those with unrestricted suckling (4·0 v. 2·2 pulses per 10 h, s.e.d. = 0·82, P < 0·05). More cows in moderate than low BCS ovulated the first DF to emerge after day 21 post partum (within 4 to 6 days) in response to restricted suckling (69 v. 25%, P < 0·05). LH pulse frequency prior to restricted suckling increased (P < 0·05) with plasma insulin concentration (categorized as low, < 5; moderate, 5 to 8; and high, >8 mIU per l). There were indications of interactions between suckling treatment and BCS (P < 0·08), and suckling treatment and plasma insulin concentration (P < 0·06), on LH pulse frequency, which suggested that calf restriction could alleviate the suppressive effects of under nutrition on episodic LH release. Amongst cows suckling once daily, the non-ovulating animals had fewer LH pulses prior to restricted suckling and smaller, slower growing DF, indicating an inability of the DF to respond to increased LH pulse frequency following calf restriction. Cows of moderate BCS, particularly those with moderate to high levels of plasma insulin (³ 5 mIU per l), responded favourably to restricted suckling. In contrast, excessively thin cows with low plasma insulin concentrations (<5 mIU per l), that had most to gain from restricted suckling, responded poorly.	
Palabras-Clave: 	BEEF COWS; HORMONA LUTEINIZANTE; INSULIN; LH; NUTRICION; OVULATION; SUCKLING.	
Thesagro: 	AMAMANTAMIENTO; BOVINOS DE CARNE; NUTRICION ANIMAL; OVULACION.	
Categoría del tema: 	--	
Registro original: 	INIA Treinta y Tres (TT)	
Ejemplares: 	TT - (101357-1) - PXI - AP - DD - PP/ANIMAL-SCIENCE/2002/QUINTANS/1 -  -  - DIS