A note on the effect of continuous ram presence on estrus onset, estrus duration and ovulation time in estrus synchronized ewes

Romano, Juan E.; Abella, D. Fernández; Villegas, N.

doi:10.1016/s0168-1591(01)00131-9

Cited by 20 publications

(10 citation statements)

References 21 publications

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“…Another factor that may have influenced the anticipation of the onset of estrus is the continued exposure of the ewes to the teasers during the period of estrus observation. When in continued contact with ewes, the male has a complete opportunity to express its full sexual behavior, including courtship and mating (ROMANO et al, 2001). Similar consideration should be taken when using hormones to induce ovulation (i.e., GnRH and LH).…”

Section: Veigamentioning

confidence: 99%

Does supplemental LH changes rate and time to ovulation and embryo yield in Santa Ines ewes treated for superovulation with FSH plus eCG?

et al. 2012

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Section: Veigamentioning

confidence: 99%

Does supplemental LH changes rate and time to ovulation and embryo yield in Santa Ines ewes treated for superovulation with FSH plus eCG?

et al. 2012

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“…However, during our observation periods, no oestrus signs of ewes were detected. When the ram is continuously present in the flock, as in our case, the duration of sexual receptivity of the ewes is reduced (Romano, Fernandez Abella, & Villegas, ).…”

Section: Methodsmentioning

confidence: 80%

Social network analysis of sheep grazing different plant functional groups

Yiakoulaki

Hasanagas

Michelaki

et al. 2018

Grass and Forage Science

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Social Network Analysis (SNA) is used for the first time to investigate the relations between plant functional groups and social structure of grazing sheep. The research was conducted on a grassland in Crete's island Lefka Ori, Greece during 2016. A flock of 20 sheep of Sfakion race was analysed as a network and the sheep as nodes. The focal sampling technique was applied during four experimental periods of four consecutive days × eight hours/day. The plant species selected by sheep during grazing were categorized into four functional groups (grasses, broad‐leaved forbs, shrubs and trees), and the proximity and conflict relations that were developed among the flock members were recorded. The tools of SNA were defined and interpreted in the sheep flock, and the Visone software is used to calculate the network variables of proximity and conflicts relations of nodes. Correlations between the plant functional groups and network variables were examined by Spearman's bivariate correlation test. Sheep collectivity was enhanced while grazing grasses and simultaneously, a tendency for hierarchization within the flock was identified. Similarly, the proximity of sheep increased during forbs’ grazing while their individualism was strengthened. When grazing shrubs, the proximity of sheep was only in part maintained while the grazing of trees seems as the most deconstructive forage option of sheep proximity relations. In general, the grazing of all plant functional groups decreases conflicts among sheep except that of trees, which was insignificant for developing such relations.

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“…No se utilizaron machos para detección de celos con el fin de reproducir las condiciones de IA de las ganaderías, así como para evitar un posible adelanto de la descarga preovulatoria de LH y de la ovulación (Signoret y Cognié, 1975;Maxwell 1986;Romano et al, 2001).…”

Section: Tratamiento Hormonalunclassified

Caracterización del pico preovulatorio de LH en ovejas Rasa Aragonesa portadoras o no del alelo FecXR (ROA®)

Crespo¹,

Pera²,

Ruiz³

et al. 2013

ITEA

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ResumenLa presencia del alelo FecX R en heterocigosis produce un incremento de la tasa de ovulación y prolificidad, así como una mayor respuesta a la eCG. Sin embargo, todavía se desconocen sus posibles efectos sobre la descarga preovulatoria de LH, lo cual es esencial para realizar la inseminación artificial en el momento óptimo. Con este objetivo, se extrajeron muestras sanguíneas a intervalos de 4-6 horas durante las 72 horas siguientes a la retirada de una esponja (FGA, 30 mg), de 50 ovejas adultas agrupadas en 5 lotes en función de su genotipo (R+ y ++; portadoras y no portadoras) y tratamiento hormonal (sin eCG, 240 ó 480 UI). Las concentraciones de LH se analizaron mediante un kit comercial ELISA. No se observó ninguna diferencia significativa en el pico preovulatorio de LH entre ovejas R+ y ++. La eCG adelantó la descarga preovulatoria de LH en ambos genotipos, sin diferencias entre ovejas R+ tratadas con 240 ó 480 UI. Estos resultados demuestran que la presencia de FecX R no afecta al pico preovulatorio de LH, independientemente de la dosis utilizada. Por lo tanto, la dosis de eCG que se aplique a las ovejas R+ estará en función de las necesidades y posibilidades de la explotación para asumir una mayor prolificidad y multiplicidad de partos. En las ovejas ++ tratadas con eCG se recomienda seguir inseminando a las 54 ± 1 horas de retirar las esponjas, como se hace habitualmente, ya que se observó una buena sincronización del pico preovulatorio de LH a las 37 horas.Palabras clave: BMP15, eCG, inseminación artificial, ovulación, PMSG, prolificidad. Abstract Preovulatory LH surge of Rasa Aragonesa ewes carrying or not the FecX R allele (ROA ® )The presence of the FecX R allele in heterozygosity (R+) increases ovulation rate and prolificacy in Rasa Aragonesa ewes, and leads to a greater response to eCG. However, their potential effects on preovulatory LH surge are still unknown, which is essential to establish the optimum time for artificial insemination. With this aim, blood samples were taken at 4-6 hours intervals during 72 hours after the removal of a 30 mg FGA sponge, from 50 adult ewes divided in 5 groups depending on their genotype (R+ and ++; carriers and non-carriers) and hormonal treatment (without eCG, 240 or 480 IU). The LH concentrations were analyzed using a commercial ELISA kit. There was no significant difference on the time of the preovulatory LH surge between R+ and ++ ewes. Treatment with eCG significantly advanced the preovulatory LH discharge in both genotypes, with no difference between R+ ewes treated with 240 or 480 IU. These results demonstrate that the presence of the FecX R allele did not affect the preovulatory LH surge, regardless of eCG dose. Therefore, the dose of eCG that should be applied to R+ ewes could be a decision of the farmer depending on the needs and possibilities of the farm to manage Lahoz et al. ITEA (en prensa), Vol. xx,(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) * Autor para correspondencia: blahozc@aragon.es DOI: pendiente the established protocol and insemi...

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A note on the effect of continuous ram presence on estrus onset, estrus duration and ovulation time in estrus synchronized ewes

Cited by 20 publications

References 21 publications

Does supplemental LH changes rate and time to ovulation and embryo yield in Santa Ines ewes treated for superovulation with FSH plus eCG?

Does supplemental LH changes rate and time to ovulation and embryo yield in Santa Ines ewes treated for superovulation with FSH plus eCG?

Social network analysis of sheep grazing different plant functional groups

Caracterización del pico preovulatorio de LH en ovejas Rasa Aragonesa portadoras o no del alelo FecXR (ROA®)

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