Título:	Effect of injectable progesterone on follicular development in lactating beef cows treated with estradiol plus a low-concentration progesterone device.
Autoria:	PFEIFER, L. F. M. MAPLETOFT, R. J. DARDAWAL, D. SINGH, J.
Afiliação:	LUIZ FRANCISCO MACHADO PFEIFER, CPAF-RO; Reuben John Mapletoft, University of Saskatchewan; Dinesh Dardawal, University of Saskatchewan; Jaswant Singh, University of Saskatchewan.
Ano de publicação:	2018
Referência:	Brazilian Journal of Veterinary Research and Animal Science, v. 25, n. 2, p. 1-8, 2018.
Conteúdo:	The effect of injectable progesterone was evaluated along with estradiol benzoate (EB) on the fate of the dominant follicle (DF) present in the ovary at the beginning of low progesterone-based TAI protocol. All cattle were given 500 µg cloprostenol im (PGF; Schering-Plough Animal Health for Estrumate, Pointe-Claire, QC, Canada) twice, 11 d apart, and allocated into two groups: Estradiol group (E group, n = 11) and Estradiol-Progesterone group (EP group, n = 11). Ten days after the second PGF (Day 0), all cattle were given an intravaginal progesterone device with half progesterone concentration (Cue-Mate with a single pod containing 0.78 g progesterone). Concurrently, all cattle were given 1.5 mg im of estradiol benzoate in 3 mL of canola oil and PGF im on Day 0 of the protocol in a crossover design, in which each cow received both treatments. Cows in the EP group also received 100 mg im progesterone (Sigma) in 2 mL of canola oil. On Day 8, progesterone devices were removed and all cattle were given PGF im. All statistical analyses were performed with SAS 9.0. The DF present on Day 0 ovulated in 76% (16/21) of cows from E group and 28.6% (6/21) of cows from EP group (P = 0.002). After progesterone device removal, the size of ovulatory follicle did not differ between groups (E group, 15.5 ± 0.43 mm vs EP group, 15.8 ± 0.98 mm; P = 0.82). These follicles ovulated in 81.3 ± 3.1 h in E group and 71.0 ± 6.1 h in EP group (P = 0.13). In conclusion, injectable progesterone reduced the proportion of cows that ovulate the dominant follicle present in the ovary at the beginning of estradiol-progesterone-based protocols. However, no difference was detected on time of ovulation after progesterone device removal between groups.
Thesagro:	Gado de Corte Rebanho Ovulação
NAL Thesaurus:	Beef cattle Livestock
Palavras-chave:	Folículo dominante Dominant follicle
Digital Object Identifier:	10.11606/issn.1678-4456.bjvras.2018.136924
Tipo do material:	Artigo de periódico
Acesso:	openAccess
Aparece nas coleções:	Artigo em periódico indexado (CPAF-RO)