Fecha/hora: 06/06/2024 11:12:30

Biblioteca(s): 	INIA La Estanzuela.	
Fecha corriente: 	21/02/2014	
Fecha de la última actualización: 	25/11/2019	
Autoria: 	CAVESTANY, D.; NEGRIN, N.; NEGRIN, R.; GROTH, J.F.	
Afiliación: 	DANIEL CAVESTANY BOCKING, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; Asesor privado Veterinaio Uruguay.; Asesor privado Veterinaio Uruguay.; Veterinarian and farm manager, Brazil and Uruguay.	
Título: 	Response of beef heifers and non-suckling beef cows to different oestrous synchronization protocols.	
Año de publicación: 	2002	
Fuente/Imprenta: 	Animal Science, 2002, Volume 74, Issue 3, Pages 547-552.	
Páginas: 	.	
DOI: 	10.1017/S135772980005270X	
Idioma: 	Inglés	
Notas: 	Article history: Received  25 September  2001/Accepted  15 January  2002.	
Contenido: 	Abstract:
The objective was to evaluate different oestrous synchronization schemes in beef cattle under range conditions. In experiment 1, 202 heifers averaging 26 months of age were assigned randomly to three treatments: (a) GnRH-PG. (no. = 44) day 0 (D0): injection of GnRH; D7: injection of PGF2?; D0 to D25 oestrous detection (OD) and artificial insemination (AI); (b) OD-PG. (no. = 45) D0 to D4; OD + AI; D5: injection of PGF2?; D5 to D25 OD + AI; and (c)Ovsynch. (no. = 113) D0: injection of GnRH; D7: injection of PGF2?; D9: injection of GnRH and 16 h later AI at fixed time. In experiment 2, 318 non-suckling cows were assigned randomly to three treatments: (a) GnRH-PG. (no. = 106) D0: injection of GnRH; D7: injection of PGF2?; D0 to D25 OD + AI; (b) GnRH-MAP-PG. (no. = 106) D0: injection of a GnRH analogue and insertion of an intravaginal sponge impregnated with 250 mg of medroxyprogesterone acetate; D7: injection of PGF2? and sponge withdrawal; D0 to D25 OD + AI; (c) controls. (no. = 106) OD and AI. The experimental period lasted 25 days and, with exception of the Ovsynch treatment, oestrous detection was carried out twice a day (a.m./p.m.) and inseminations performed 12 h later. The pregnancy rates assessed by ultrasonography 30 days after AI were: experiment 1: (a) 30·0%; (b) 28·6% and (c) 62·3% (P < 0·05); experiment 2: (a) 60·2%; (b) 57·8% and (c) 45·5% (P < 0·05). It is concluded that in heifers and non-suckling cows, oestrous synchronization treatments result in higher pregnancy rates. In non-suckling cows, the addition of a progestagen did not improve the response.	
Palabras-Clave: 	BEEF CATTLE; GnRH; OESTRUS; PROSTAGLANDINS.	
Thesagro: 	REPRODUCCION ANIMAL.	
Categoría del tema: 	L53 Fisiología Animal - Reproducción	
Registro original: 	INIA La Estanzuela (LE)	
Ejemplares: 	LE - (36963-1) - PXI - AP - DD - PP/Animal Science/2002 -  -  - DIS