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 | Acesso ao texto completo restrito à biblioteca da Embrapa Caprinos e Ovinos. Para informações adicionais entre em contato com cnpc.biblioteca@embrapa.br. |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
19/11/2003 |
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Data da última atualização: |
28/08/2023 |
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Autoria: |
DRIANCOURT, M. A. |
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Título: |
Regulation of ovarian follicular dynamics in farm animals. Implications for manipulation of reproduction. |
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Ano de publicação: |
2001 |
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Fonte/Imprenta: |
Theriogenology, v. 55, n. 6, p. 1211-1239, Apr., 2001. |
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DOI: |
10.1016/s0093-691x(01)00479-4. |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract: In this review, the main features of folliculogenesis are summarized and compared among species. In the past few years, ultrasonography has clarified follicle growth patterns, and our understanding of follicle maturation has improved considerably. As the follicles develop towards the ovulatory stage, three features appear to be highly conserved across all species: 1) the sequence of events (recruitment, selection and dominance); 2) the sequential need for gonadotropins (FSH for recruitment, LH for dominance) and 3) the large variability of numerical parameters (number of waves per cycle, number of follicles per wave) as well as temporal requirements (time of selection, duration of dominance). In addition, specific follicles may also have variable gonadotropin requirements (thresholds). When patterns of follicle development at different physiological states are compared across species, follicular waves were detected in cattle, sheep and horses and during the prepubertal period in swine, suggesting that ovaries of all species operate on a wave basis unless they are prevented from doing so. Efficient estrus control treatments should have the ability to affect 1) the wave pattern by preventing the development of persistent dominant follicles containing aging oocytes, and 2) the recruitment of the future ovulatory follicle whatever the stage of the wave at the time of treatment. This would allow synchronous ovulation of a growing dominant follicle. Manipulation of the luteal phase follicular waves after mating or AI may also optimize fertility. Superovulation is still an efficient technique to obtain progeny from genetically valuable females. Administration of exogenous gonadotropins acts to reveal the underlying ovarian variability. Ovarian response of each female depends on the number of gonado-sensitive follicles present at the time when treatment is initiated. Identification of the number of such follicles for each female would improve efficacy of superovulation, by allocating potential nonresponders to other techniques (OPU/FIV). One of the main components of the within female response to superovulation is the stage of the wave when gonadotropins are injected. Treatment in the absence of a dominant follicle ensures a response close to the female's specific maximum. The development of practical approaches to achieve this still requires further research. MenosAbstract: In this review, the main features of folliculogenesis are summarized and compared among species. In the past few years, ultrasonography has clarified follicle growth patterns, and our understanding of follicle maturation has improved considerably. As the follicles develop towards the ovulatory stage, three features appear to be highly conserved across all species: 1) the sequence of events (recruitment, selection and dominance); 2) the sequential need for gonadotropins (FSH for recruitment, LH for dominance) and 3) the large variability of numerical parameters (number of waves per cycle, number of follicles per wave) as well as temporal requirements (time of selection, duration of dominance). In addition, specific follicles may also have variable gonadotropin requirements (thresholds). When patterns of follicle development at different physiological states are compared across species, follicular waves were detected in cattle, sheep and horses and during the prepubertal period in swine, suggesting that ovaries of all species operate on a wave basis unless they are prevented from doing so. Efficient estrus control treatments should have the ability to affect 1) the wave pattern by preventing the development of persistent dominant follicles containing aging oocytes, and 2) the recruitment of the future ovulatory follicle whatever the stage of the wave at the time of treatment. This would allow synchronous ovulation of a growing dominant follicle. Manipulation of the l... Mostrar Tudo |
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Thesaurus Nal: |
Cattle; Estrus synchronization; Follicle-stimulating hormone; Goats; Luteinizing hormone; Ovarian follicles; Reproduction; Seasons; Sheep; Superovulation. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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Marc: |
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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| Registros recuperados : 2 | |
| 1. |  | YORINORI, J. T.; ALMEIDA, A. M. R.; HOMECHIN, M.; MIRANDA, L. C.; KIIHL, R. A. S.; POLA, J. N.; TAMIOZO, I. H. Cancro-da-haste da soja: descricao da doenca, distribuicao geografica, determinacao de niveis de danos, caracterizacao do patogeno, transmissao pela semente e testes de patogenicidade. In: EMBRAPA. Centro Nacional de Pesquisa de Soja (Londrina, PR). Resultados de pesquisa de soja 1988/89. Londrina, 1989. p.160-164. (EMBRAPA-CNPSo. Documentos, 43).| Biblioteca(s): Embrapa Soja. |
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| 2. | | YORINORI, J. T.; ALMEIDA, A. M. R.; HOMECHIN, M.; MIRANDA L. C.; KIIHL, R. A. S.; POLA, J. N.; TAMIOZO, I. H. Epifitia do cancro da haste da soja nos municiípios de castro, Palmeira, Ponta Grossa e Tibagi, no Paraná e Rondonópolis, no Mato Grosso, na safra 1988/89. In: SEMINÁRIO NACIONAL DE PESQUISA DE SOJA, 5., 1989, Campo Grande. Resumos... Londrina: Embrapa-CNPSo, 1989. p. 22-23.| Biblioteca(s): Embrapa Soja. |
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| Registros recuperados : 2 | |
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