Release of prostaglandin F-2  and the timing of events associated with luteolysis in ewes with oestrous cycles of different lengths

Zarco, L.; Stabenfeldt, G. H.; Quirke, J. F.; Kindahl, H.; Bradford, G. E.

doi:10.1530/jrf.0.0830517

Cited by 74 publications

(38 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In all groups the average cycle length was close to the longest individual cycle length reported in other breeds (Zarco et al 1988). However, it should be taken into account that in the present study it was assumed that the onset of estrus (and thus the onset of the estrous cycle) occurred in all animals 48 h after sponge removal (Wildeus 2000).…”

Section: Discussionsupporting

confidence: 83%

See 1 more Smart Citation

Effect of stage of the estrous cycle at the time of initial exposure to rams on the ovarian activity of Pelibuey ewes

Jarquin¹,

Roldán²,

Zarco³

et al. 2014

CZECH J ANIM SCI

Self Cite

View full text Add to dashboard Cite

Forty non-lactating, cyclic adult Pelibuey ewes were randomly divided into six groups. Estrus was synchronized within each group using intravaginal sponges and prostaglandin F2α injection at the time of the sponge removal. The sponges were inserted and removed on different dates in each group, but all the groups except the control one were first exposed to rams on the same date (July 17 th ), so that at the time of the first exposure the ewes were either on day 0 (group D0; n = 7), 3 (group D3; n = 7), 8 (group D8; n = 7), 12 (group D12; n = 7) or 14 (group D14; n = 7) of their synchronized estrous cycle. Thereafter the ewes of these groups remained continuously exposed to the males until all the females showed estrus. The ewes in the control group (CG; n = 5) remained isolated from all the males, except for 5-minute periods at the time of estrus detection, which was carried out three times a day. Progesterone concentrations were determined in plasma samples taken daily from two days before the initial exposure to the males until the onset of the next estrus. There were no differences in estrous cycle length between the groups exposed to rams and the control group (P > 0.05). The interval from the assumed onset of the estrous cycle (48 h after sponge removal) until the occurrence of luteolysis was not different between the control group and any of the groups exposed to the males. The interval from luteolysis to estrus was not modified by exposure to the males (P > 0.05). Estrus duration was shorter (P < 0.06) in the control group than in group D3. It is concluded that the exposure of cyclic Pelibuey ewes to males does not advance the time of luteolysis and does not affect the length of the estrous cycle. Therefore, the male effect does not synchronize the next estrus of cyclic Pelibuey ewes.

show abstract

Section: Discussionsupporting

confidence: 83%

“…Zarco et al (1988) found that the timing of events after the onset of luteolysis is remarkably constant in sheep, and not related to the duration of the estrous cycle, making alterations in the duration of proestrus an unlikely cause of differences in the estrous cycle length.…”

Section: Discussionmentioning

confidence: 89%

Effect of stage of the estrous cycle at the time of initial exposure to rams on the ovarian activity of Pelibuey ewes

Jarquin¹,

Roldán²,

Zarco³

et al. 2014

CZECH J ANIM SCI

Self Cite

View full text Add to dashboard Cite

show abstract

“…Embriões viáveis devem estar presentes no útero até o dia 13 do diestro para fornecer sinal luteotrópico (Pineda, 1989). Se não há embriões viáveis presentes, o corpo lúteo regride rapidamente sob a influência da PGF2a, e a ovelha inicia outro ciclo (Zarco et al, 1988). Este processo repete-se durante subseqüentes ciclos até o final da estação reprodutiva, se a ovelha não se tornar prenhe.…”

Section: Groups With Different Superscripts Within the Same Columms Aunclassified

Concentrações plasmáticas de progesterona em borregas lanadas e deslanadas no período de abril a novembro, no Estado de São Paulo

Sasa

Teston²,

Rodrigues

et al. 2002

R. Bras. Zootec.

View full text Add to dashboard Cite

RESUMO -Objetivou-se com este trabalho o fornecimento de informações sobre o padrão de secreção da progesterona (P 4 ) e as características de manifestação do ciclo estral em borregas lanadas e deslanadas, durante o período de abril a novembro, no Estado de São Paulo. Amostras de sangue foram coletadas da veia jugular de 12 borregas das raças Santa Inês (SI), Romney Marsh (RM) e Suffolk (SU), e as concentrações foram determinadas pelo método de radioimunoensaio utilizando-se kits comerciais. O estro foi detectado por machos vasectomizados (impregnados com tinta pó xadrez + óleo comestível na região peitoral) em 31 borregas (10 SI, 11 RM e 10 SU). O estro foi determinado pelo confronto da observação de fêmeas marcadas pelos machos vasectomizados e dos valores de concentrações plasmáticas de progesterona inferiores a 1 ng/mL. Os resultados mostraram que a maioria dos ciclos estrais foi de duração normal (14 -19 dias) para todas as raças. A duração dos ciclos de duração normal das borregas SU foi inferior aos das borregas SI e RM, as quais não diferiram entre si. Não houve diferença entre as raças na duração dos ciclos curtos (< 14 dias) e longos (20 -26 dias). O padrão de secreção de P 4 mostrou a presença de ciclos estrais múltiplos (27 -57 dias) indicando a incidência de ovulações silenciosas. As borregas SI encontravam-se em atividade cíclica reprodutiva apresentando valores que variaram de 0,08 a 7,36 ng/mL, enquanto que as raças RM e SU encontravam-se em atividade somente no período de abril a julho com valores que variaram de 0,13 a 7,05 ng/mL e de 0,15 a 7,30 ng/mL, respectivamente. De agosto a novembro, estas duas raças encontravam-se em anestro. Conclui-se que, em São Paulo, a raça SI não possui estacionalidade no ciclo reprodutivo como as raças RM e SU. Palavras-chave: ciclo estral, ovinos, progesterona, raças Plasma Concentrations of Progesterone in Hair and Wool Ewe Lambs from April toNovember, in São Paulo State ABSTRACT -The goal of this experiment was to provide information about the pattern of progesterone secretion (P 4 ) and on the oestrus cycle characteristics in hair and wool ewe lambs, from April to November, in São Paulo State. Blood samples from jugular vein were collected from 12 ewe lambs Santa Inês (SI), Romney Marsh (RM) and Suffolk (SU) breeds, and the concentrations were determined by radioimmunoassay method, using commercial kits. Oestrus was detected by using vasectomized rams (fitted with raddle crayons + comestible oil on pectoral area) in 31 ewe lambs (10 SI, 11 RM and 10 SU). The oestrus was determined by confronting the observation of marked females by vasectomized rams and values of plasma progesterone concentrations lower than 1 ng/mL. The results showed that the majority of oestrus cycles were of normal lenght (14 -19 days) for all breeds. The normal cycles lenght for the SU ewe lambs was shorter than SI and RM, which did not differ from each other. There was no difference for short (<14 days) and long (20 -26 days) oestrus cycles duration between the breeds. The pattern of P...

show abstract

“…Já no bovino, a (FARIN et al, 1990;ROBERTS, 1991;ROBERTS et al, 1991). Como resposta, o IFNT inibe a transcrição de receptores de estrógenos (ESR1; SPENCER & BAZER, 1996) e ocitocina (OXTR; SPENCER & BAZER, 1996;CHEN et al, 2006) no endométrio inibindo a luteólise (ZARCO et al, 1988a;ZARCO et al, 1988b). Na ovelha, esse momento corresponde à elongação do blastocisto que passa de uma forma esférica para filamentosa entre os dias 10 e 17 da gestação (SPENCER et al, 2004) Receptores de interferon tipo I e genes estimulados por interferons (ISGs) Os receptores de interferon tipo I (IFNAR1 e IFNAR2) são expressos em todos os tecidos corporais e têm como função principal mediar respostas antivirais.…”

Section: Receptores De Prostaglandinasunclassified

Função do interferon-tau durante o reconhecimento materno da gestação em ruminantes

Antoniazzi¹,

Henkes

Oliveira³

et al. 2011

Cienc. Rural

View full text Add to dashboard Cite

RESUMO O reconhecimento materno da gestação é o período em que o concepto sinaliza sua presença para a mãe. Em ruminantes, este período coincide com o alongamento do embrião e a máxima produção de interferon-tau (IFNT ABSTRACT Maternal recognition of pregnancy is the period when the conceptus signals its presence to the dam. In ruminants, it requires conceptus elongation, which coincides with maximum production of interferon-tau (IFNT). Conceptus IFNT acts in a paracrine manner silencing estrogen receptor alpha (ESR1) and oxytocin receptor (OXTR) in the luminal

show abstract

Release of prostaglandin F-2 and the timing of events associated with luteolysis in ewes with oestrous cycles of different lengths

Cited by 74 publications

References 20 publications

Effect of stage of the estrous cycle at the time of initial exposure to rams on the ovarian activity of Pelibuey ewes

Effect of stage of the estrous cycle at the time of initial exposure to rams on the ovarian activity of Pelibuey ewes

Concentrações plasmáticas de progesterona em borregas lanadas e deslanadas no período de abril a novembro, no Estado de São Paulo

Função do interferon-tau durante o reconhecimento materno da gestação em ruminantes

Contact Info

Product

Resources

About