Effect of estradiol cypionate on estrus expression and pregnancy in timed artificially inseminated beef cows

Pfeifer, Luiz Francisco Machado; Moreira, Elizângela Mírian; Silva, George Moreira da; Souza, V.; Nunes, Vanessa Rachele Ribeiro; Andrade, Jéssica de Souza; Neves, P. C. F.; Ferreira, Rogério

doi:10.1016/j.livsci.2019.103886

Cited by 11 publications

(6 citation statements)

References 29 publications

(41 reference statements)

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“…Our results are in agreement with a previous study that compared EC, EC+GnRH or GnRH for ovulation induction in a progesterone-estradiol based protocol, which also did not observe differences in pregnancy rate on days 31 and 60 after TAI, reviewed by Consentini et al (2021). It is well established that EC administration induces estrous behavior (Pfeifer et al, 2020) and that recipient cows that show estrus are more likely to become pregnant (Frade et al, 2014;Bó and Cedeño, 2018). Although estrus detection was not performed in the present study, treatment with EC had no beneficial effect on the percentage of cows that received an embryo and on pregnancy rate.…”

Section: Discussionsupporting

confidence: 93%

“…Although EC has been widely used at progesterone device withdrawal, eliminating the need for animal handling before timed artificial insemination (TAI), there is greater variation in the time of ovulation compared to GnRH treatment (Souza et al, 2009). In contrast, administering estradiol at proestrus regulates endometrial gene expression (Sá et al, 2017) and increases the proportion of cows that show estrus (Pfeifer et al, 2020), which are more likely to become pregnant after TAI (Barbosa et al, 2022) or TET (Frade et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Does combining estradiol cypionate and GnRH for ovulation induction in recipient cows increase pregnancy rate after timed embryo transfer?

et al. 2022

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Estradiol cypionate (EC) or GnRH have been widely used for ovulation induction in timed embryo transfer (TET). EC administration increases the proportion of cows that show estrus, whereas GnRH promotes more synchronized ovulations. The aim of the present study was to evaluate the potential beneficial effects of combining EC and GnRH in TET. In experiment 1, no difference was observed on serum progesterone concentrations on Day 6 and 13 after GnRH treatment between GnRH and EC+GnRH groups. In experiment 2, pregnancy per embryo transfer (P/ET) did not differ (p = 0.69) between GnRH (62.8%) and EC+GnRH (58.7%) groups. In conclusion, combining EC and GnRH for ovulation induction does not increase progesterone secretion and pregnancy rate after TET in cattle.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Does combining estradiol cypionate and GnRH for ovulation induction in recipient cows increase pregnancy rate after timed embryo transfer?

et al. 2022

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“…No presente estudo houve uma associação entre as dimensões foliculares e a expressão do estro, corroborando aos achados de algumas pesquisas que indicaram uma relação entre o estro antes da IATF e o maior diâmetro do folículo ovulatório [36][37][38]44,45]. De forma semelhante, Ferraz et al [21] desenvolveram trabalhos com objetivo de avaliar a associação entre a intensidade de expressão do estro de fêmeas bovinas submetidas a IATF e o diâmetro do folículo ovulatório, constatando diferença entre os animais que expressaram estro e os que não expressaram estro, obtendo média de 12,61 ± 3,34 mm e 10,30 ± 2,98 mm, respectivamente.…”

Section: Discussionunclassified

Effect of the Estrus Expression on Follicular and Luteal Morphofunctional Characteristics and Fertility in Bos indicus females Synchronized for FTAI

Menezes

Batista

Sousa

et al. 2021

Acta Scientiae. Vet.

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Background: Recent studies have been conducted with the aim of improving the fertility rates in the FTAI programs in beef females. The observation of the estrus expression constitutes an important indicator of fertility in zebu females. Therefore, this work has as an objective to evaluate the impact of the estrus expression on the follicular, luteal and fertility morphofunctional characteristics of Nelore females synchronized for FTAI.Materials, Methods & Results: Sixty five lactating female Nelore (Bos taurus indicus) were used. On a random day, denominated day 0 (D0), the 65 Nelore females received a progesterone-releasing device associated to the application of 2.0 mg of estradiol benzoate intramuscularly (IM). On D9, the progesterone-releasing intravaginal devices were removed and was administered 500 μg of cloprostenol sodium IM; 0.6 mg of estradiol cypionate IM and 300 UI of Equine Chorionic Gonadotropin IM. At this point, the animals were marked with a marking stick for the determination of the estrus expression. On D11 of the synchronization protocol, the animals were characterized in two groups: without estrus expression (WO/ ESTRUS) and with estrus expression (W/ ESTRUS). The evaluation of the follicle diameter (FOLD), of the follicle wall area (FOLA), of the follicle wall vascularization (FOLV) and the percentage of vascularization in the area of the preovulatory follicle wall (%FOLV) were conducted on D11 using B-mode ultrasonography and color Doppler and then the artificial inseminations were performed. The evaluation of the corpus luteum diameter (CLD), the total area of the corpus luteum (CLA), of the area of vascularization of the corpus luteum (CLV), of the percentage of vascularization of the in the area of the corpus luteum (% CLV) and the collection of blood for the evaluation of the serum levels of progesterone were carried out on D24. The analysis of the serum progesterone concentration were performed by the chemiluminescence method using the Access immunoassay systems Progesterone, with a sensitivity of 0.1 ng/mL. The diagnosis of gestation was carried out by transrectal ultrasonography on D45. The animals of the WITH ESTRUS group presented superior FOLD, FOLA, FOV (P < 0.05) averages to those presented by the cows of the WITHOUT ESTRUS group. In relation to the luteal characteristics, in the WITH ESTRUS group the cows exhibited averages for CLD, CLA, CLV and P4 significantly higher than those of the WITHOUT ESTRUS group. However, the bovines of the WITH ESTRUS group presented a % CLV similar to the presented by the females of the WITHOUT ESTRUS group. As for the fertility rates, there was difference between the experimental groups WITH ESTRUS and WITHOUT ESTRUS.Discussion: The present work demonstrated the impact of the estrus expression on the follicular morphological parameters, therefore in accordance with other studies. These authors show a relation between the estrus expression and levels of estradiol, which is directly related to the sperm transport in the female reproductive tract, oocyte maturation and fertilization directly affecting the fertility of females submitted to the FTAI program. Similarly, there was an interrelation between the estrus expression and the luteal morphological parameters, corroborating with the findings of some researches, where were verified higher luteal morphological parameters associated to higher conception rates in cows that demonstrated estrus behavior in the FTAI. Therefore, the estrus detection can be used as a tool to direct matings in synchronization protocols, promoting the identification of the animals with a higher probability of conception, owing to better follicular and luteal hemodynamic conditions.

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“…In Brazil, protocols based on P4 and estradiol are the most used in beef cattle ( Bó et al, 2013 ), and the use of estradiol cypionate (EC) as an ovulation inducer brings the advantage of reducing one day of cattle handling, as it is injected on the day of IVD removal, compared to estradiol benzoate (EB), which is usually injected 24 h after IVD removal ( Colazo et al, 2003 ). However, the use of this hormone is associated with the artificial expression of estrus ( Pfeifer et al, 2020 ) and with the dispersion of ovulation ( Souza et al, 2009 ).…”

Section: Introductionmentioning

confidence: 99%

Does GnRH treatment at TAI regardless of estrus occurrence increase pregnancy rate in crossbred Bos taurus suckled cows?

Fernandes,

Velho,

Santos

et al. 2024

Anim. Reprod.

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The impact of GnRH treatment on the day of TAI in beef cows has received limited investigation, especially concerning its association with estrus expression. Consequently, two experiments were conducted to assess the potential of GnRH treatment on the day of TAI to enhance fertility according to the expression or not of estrus in beef cows. Experiment 1 aimed to determine ovulation rate and luteal function, while Experiment 2 aimed to determine the effect of the two GnRH treatment approaches on pregnancy rate. In Experiment 1, multiparous Brangus suckling cows (n = 17) were submitted to an 8-day TAI protocol. Estrus occurrence was evaluated based on chalk removal on D10 (TAI) and cows were assigned to receive GnRH (25µg lecirelin; im) according to the group: GnRH (n = 7), regardless of estrus expression; or selectGnRH (n = 10), only cows not detected in estrus. Ovulation rate occurring until 77h after IVD removal did not differ (p = 0.17) between GnRH (85.7%; 6/7) and selectGnRH (100%; 10/10). Also, corpus luteum size and serum progesterone concentration were not affected (p>0.05) by treatments. In Experiment 2, crossbred taurine suckled cows (n = 384) were submitted to the same protocol as described in Experiment 1 and were randomly allocated to GnRH or selectGnRH groups. There was no difference in P/AI between groups (selectGnRH = 55.6%; GnRH = 54.3%; p = 0.7) 30 days after TAI. As expected, there was a pronounced effect (p<0.0001) of estrus expression on P/AI (Estrus = 61.5%; No estrus = 33.0%), regardless of group. In summary, ovulation timing and rate and luteal function did not differ between groups. Also, GnRH administration only in cows that do not show estrus is recommended, considering hormone savings and similar conception rate.

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Effect of estradiol cypionate on estrus expression and pregnancy in timed artificially inseminated beef cows

Cited by 11 publications

References 29 publications

Does combining estradiol cypionate and GnRH for ovulation induction in recipient cows increase pregnancy rate after timed embryo transfer?

Does combining estradiol cypionate and GnRH for ovulation induction in recipient cows increase pregnancy rate after timed embryo transfer?

Effect of the Estrus Expression on Follicular and Luteal Morphofunctional Characteristics and Fertility in Bos indicus females Synchronized for FTAI

Does GnRH treatment at TAI regardless of estrus occurrence increase pregnancy rate in crossbred Bos taurus suckled cows?

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