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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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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
01/08/1992 |
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Data da última atualização: |
29/11/2023 |
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Autoria: |
LAMOND, D. R. |
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Título: |
Seasonal changes in the occurrence of ostrus following progesterone suppression of ovarian function in the Merino ewe. |
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Ano de publicação: |
1964 |
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Fonte/Imprenta: |
Journal of Reproduction and Fertility, v. 8, n. 1, p. 101-114, Aug. 1964. |
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DOI: |
10.1530/jrf.0.0080101 |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract: Three groups of Merino ewes (a total of 150) kept in yards were studied for a period of 1 year. Vasectomized rams were with one group and occurrence of oestrus was noted. The presence and number of corpora lutea were observed by laparotomy at 6-week intervals. The annual rhythms in these characteristics were determined. A second group of ewes received progesterone treatments at intervals of 6 weeks. Half the ewes were with vasectomized rams continuously but rams were with the others for only 1 week after the final progesterone injection. The period from the final injection to the onset of oestrus was determined. Introduction of rams increased the number of ewes showing oestrus at the beginning (late summer) and end (late winter) of the breeding season. The period to onset of oestrus was related to dose and frequency of progesterone injections, the time of the year, and introduction of rams. Periods to onset of oestrus became progressively longer after mid-winter (June) and a proportion of progesterone-treated ewes did not show oestrus in the 1 week period after cessation of progesterone injections in July, at a time when all untreated ewes were experiencing oestrous cycles. The implications of the seasonal change in the effects of progesterone on the ewes are discussed in relation to the sexual season. A third group of ovariectomized ewes received progesterone followed by oestrogen, also at intervals of 6 weeks. The number of ewes showing oestrus during the period January to June was dependent on the dose of progesterone independently of the effect of dose of oestrogen. The relationship did not hold at other times. In general, there was considerable heterogeneity in mean responses and slopes of the dose-response lines. MenosAbstract: Three groups of Merino ewes (a total of 150) kept in yards were studied for a period of 1 year. Vasectomized rams were with one group and occurrence of oestrus was noted. The presence and number of corpora lutea were observed by laparotomy at 6-week intervals. The annual rhythms in these characteristics were determined. A second group of ewes received progesterone treatments at intervals of 6 weeks. Half the ewes were with vasectomized rams continuously but rams were with the others for only 1 week after the final progesterone injection. The period from the final injection to the onset of oestrus was determined. Introduction of rams increased the number of ewes showing oestrus at the beginning (late summer) and end (late winter) of the breeding season. The period to onset of oestrus was related to dose and frequency of progesterone injections, the time of the year, and introduction of rams. Periods to onset of oestrus became progressively longer after mid-winter (June) and a proportion of progesterone-treated ewes did not show oestrus in the 1 week period after cessation of progesterone injections in July, at a time when all untreated ewes were experiencing oestrous cycles. The implications of the seasonal change in the effects of progesterone on the ewes are discussed in relation to the sexual season. A third group of ovariectomized ewes received progesterone followed by oestrogen, also at intervals of 6 weeks. The number of ewes showing oestrus during the period ... Mostrar Tudo |
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Palavras-Chave: |
Raça Merino; Sincronizacao. |
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Thesagro: |
Ciclo Estral; Merino; Ovino; Reprodução. |
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Thesaurus Nal: |
Estrus synchronization; Females; Ovulation; Progesterone; Reproduction; Sheep. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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Marc: |
LEADER 02570naa a2200277 a 4500
001 1519497
005 2023-11-29
008 1964 bl uuuu u00u1 u #d
024 7 $a10.1530/jrf.0.0080101$2DOI
100 1 $aLAMOND, D. R.
245 $aSeasonal changes in the occurrence of ostrus following progesterone suppression of ovarian function in the Merino ewe.$h[electronic resource]
260 $c1964
520 $aAbstract: Three groups of Merino ewes (a total of 150) kept in yards were studied for a period of 1 year. Vasectomized rams were with one group and occurrence of oestrus was noted. The presence and number of corpora lutea were observed by laparotomy at 6-week intervals. The annual rhythms in these characteristics were determined. A second group of ewes received progesterone treatments at intervals of 6 weeks. Half the ewes were with vasectomized rams continuously but rams were with the others for only 1 week after the final progesterone injection. The period from the final injection to the onset of oestrus was determined. Introduction of rams increased the number of ewes showing oestrus at the beginning (late summer) and end (late winter) of the breeding season. The period to onset of oestrus was related to dose and frequency of progesterone injections, the time of the year, and introduction of rams. Periods to onset of oestrus became progressively longer after mid-winter (June) and a proportion of progesterone-treated ewes did not show oestrus in the 1 week period after cessation of progesterone injections in July, at a time when all untreated ewes were experiencing oestrous cycles. The implications of the seasonal change in the effects of progesterone on the ewes are discussed in relation to the sexual season. A third group of ovariectomized ewes received progesterone followed by oestrogen, also at intervals of 6 weeks. The number of ewes showing oestrus during the period January to June was dependent on the dose of progesterone independently of the effect of dose of oestrogen. The relationship did not hold at other times. In general, there was considerable heterogeneity in mean responses and slopes of the dose-response lines.
650 $aEstrus synchronization
650 $aFemales
650 $aOvulation
650 $aProgesterone
650 $aReproduction
650 $aSheep
650 $aCiclo Estral
650 $aMerino
650 $aOvino
650 $aReprodução
653 $aRaça Merino
653 $aSincronizacao
773 $tJournal of Reproduction and Fertility$gv. 8, n. 1, p. 101-114, Aug. 1964.
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| 3. |  | TRAVASSO, M. I.; MAGRIN, G. O.; BAETHGEN, W. E.; CASTAÑO, J. P.; RODRIGUEZ, G. R.; PIRES, J. L. F.; GIMENEZ, A.; CUNHA, G. R. da; FERNANDES, J. M. C. Maize and soybean cultivation in Southeastern South America: adapting to climate change. In: LEARY, N.; ADEJUWON, J.; BARROS, V.; BURTON, I.; KULKARNI, J.; LASCO, R. Climate change and adaptation. London: Earthscan, 2008. p. 332-352.| Tipo: Capítulo em Livro Técnico-Científico |
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