Data/hora: 07/06/2024 09:41:25

Biblioteca(s): 	Embrapa Pecuária Sudeste.	
Data corrente: 	17/12/2008	
Data da última atualização: 	07/03/2023	
Autoria: 	MACHADO, R.; BERGAMASCHI, M. A. C. M.; BARBOSA, R. T.; OLIVIEIRA, C. A.; BINELLI, M.	
Afiliação: 	RUI MACHADO, CPPSE; MARCO AURELIO C MEIRA BERGAMASCHI, CPPSE; ROGERIO TAVEIRA BARBOSA, CPPSE; C. A. OLIVEIRA, USP-FMVZ; M. BINELLI, USP-FMVZ.	
Título: 	Ovarian function in Nelore (Bos taurus indicus) cows after post-ovulation hormonal treatments.	
Ano de publicação: 	2008	
Fonte/Imprenta: 	Theriogenology, v. 69, n. 7, 798-804, apr. 2008.	
DOI: 	10.1016/j.theriogenology.2007.10.025	
Idioma: 	Inglês	
Conteúdo: 	Maternal recognition of pregnancy in the cow requires successful signaling by the conceptus to block luteolysis. Conceptus growth and function depend on an optimal uterine environment, regulated by luteal progesterone. The objective of this study was to test strategies to optimize luteal function, as well as prevent a dominant follicle from initiating luteolysis. Nelore (Bos taurus indicus) beef cows (n = 40) were submitted to a GnRH/PGF2?/GnRH protocol. Cows that ovulated from a dominant ovarian follicle (ovulation = Day 0) were allocated to receive: no additional treatment (GC; n = 7); 3000 IU of hCG on Day 5 (GhCG; n = 5); 5 mg of estradiol-17? on Day 12 (GE2; n = 6); or 3000 IU of hCG on Day 5 and 5 mg of estradiol-17? on Day 12 (GhCG/E2; n = 5). Ultrasonographic imaging of the ovaries, assessment of plasma progesterone concentration, and detection of estrus were done daily from Day 5 to the day of subsequent ovulation. Treatment with hCG induced an accessory CL, increased CL volume, and plasma progesterone concentration throughout the luteal phase (P < 0.01). Estradiol-17? induced atresia and recruitment of a new wave of follicular growth; it eliminated a potentially estrogen-active, growing ovarian follicle within the critical period for maternal recognition of pregnancy, but it also hastened luteolysis (Days 16 or 17 vs. Days 18 or 19 in non-treated cows). In conclusion, the approaches tested enhanced luteal function (hCG) and altered ovarian follicular dynamics (estradiol-17?), but were unable to extend the life-span of the CL in Nelore cows.	
Palavras-Chave: 	Antiluteolytic strategies; Ovary.	
Thesagro: 	Estradiol.	
Thesaurus Nal: 	cattle; gonadotropins.	
Categoria do assunto: 	L Ciência Animal e Produtos de Origem Animal	
Registro original: 	Embrapa Pecuária Sudeste (CPPSE)	
Exemplares: 	CPPSE - (18143-1) - UPC - AP - DD - PROCI-2008.00191 - MAC - 2008.00191 - DIS