Effect of equine chorionic gonadotropin (eCG) administration and proestrus length on ovarian response, uterine functionality and pregnancy rate in beef heifers inseminated at a fixed-time

Núñez-Olivera, R.; Cuadro, F.; Bosolasco, D.; Brun, V. de; Mata, John D.; Brochado, C.; Meikle, A.; Bó, G. A.; Menchaca, A.

doi:10.1016/j.theriogenology.2020.03.031

Cited by 18 publications

(11 citation statements)

References 32 publications

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“…The lack of significant difference for pregnancy rate of FTET between the two protocols here evaluated disagree from Núñez-Olivera et al (2020) and Menchaca et al (2017) results, who observed a greater pregnancy rate for the J-Synch protocol using IAFT and FTET, respectively. Here, a higher utilization rate of recipients with the J-Synch protocol (85%) was found and a trend (P=0.0989) to lower embryonic loss, compared to the conventional protocol.…”

Section: Discussioncontrasting

confidence: 84%

“…The benefits of the J-Synch protocol is related to an increase in growth rate of the dominant ovulatory follicle, associated to greater pre-ovulatory estradiol and post-ovulatory progesterone concentrations. This is explained because of a complex modulation of the expression of the estrogen and progesterone receptors and other growth factor, such as insulin-like growth factor (IGF1), which prepare the uterine environment to receive the embryo and for pregnancy establishment ( De la Mata and Bó, 2012 ; Bó et al, 2016 ; De la Mata et al, 2018 ; Macmillan et al, 2020 ; Núñez-Olivera et al, 2020 ). Finally, the method to produce the embryo ( in vivo or in vitro ) transferred, influences pregnancy rate ( Pontes et al, 2009 ; Ferraz et al, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

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Factors associated with pregnancy rate in fixed-time embryo transfer in cattle under humid-tropical conditions of México

2020

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The objective was to determine the effect of some factors on pregnancy rate of fixed-time embryo transfer (FTET), in cows and heifers kept under Mexican tropical conditions. Recipients females (n=405) grazing in pastures were selected according to breed group (Zebu and crosses), parity (nulliparous and multiparous), body condition score (BCS) and the presence of a corpus luteum (CL). The females were synchronized on day 0 using a progesterone vaginal device and 2 mg estradiol benzoate (EB), two groups were established. Group 1 (conventional protocol) were animals in which the progesterone device was removed on day 7. At this time, also received an injection of 50 mg cloprostenol sodium and 1 mg estradiol cypionate. Animals also received 300 IU (heifers) or 360 IU (cows) of eCG. Group 2 (J-Synch protocol) were animals in which the progesterone device was removed on day 6. Cloprotenol and eCG injections were applied as in Group 1. Additionally, on day 9, animals of group 2 received 0.01 mg buserelin acetate. Embryo transfer of in vivo or in vitro was done on day 16 and pregnancy diagnosis was realized by ultrasonography on days 23 and 53 after FTET. Statistical analyses were carried out using Chi-square tests and logistic regression. Pregnancy rate varied between farms (P<0.05). The highest pregnancy rate was for multiparous cows (66%). The recipient utilization rate was better in the J-Synch protocol (85%), and in vivo embryos (75%) had higher pregnancy rate. The diameter of the follicle and the CL had no effect on pregnancy rate (P>0.05). However, the logistic regression determined that the only significant factor on pregnancy rate was the type of embryo. In conclusion, pregnancy rate in FTET females was higher for in vivo embryos than for in vitro embryos in cows evaluated under humid tropical conditions in Mexico.

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Section: Discussioncontrasting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Factors associated with pregnancy rate in fixed-time embryo transfer in cattle under humid-tropical conditions of México

2020

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“…These results suggest that both receptors are essential for sheep reproductive function in the uterus, but its expression is changeable in uterus tissues 30 . It is known that estrogens during the follicular phase up-regulate both PRs and ERα in the uterus of most mammalian and P4 during the luteal phase down-regulates them; it should be taken into account that mRNA expressions do not always reflect protein concentration 37 . Our research results in which the mRNA expression for PRs was the highest in pregnancy in myometrium conformed other studies.…”

Section: Discussionmentioning

confidence: 99%

Regulation of uterine function during estrous cycle, anestrus phase and pregnancy by steroids in red deer (Cervus elaphus L.)

Kotlarczyk

Grzyb

Korzekwa

2021

Sci Rep

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Steroid synthesis and production in ruminant uterus is not obvious, especially in seasonally reproduced. We compared steroid production by investigating enzymes involved in red deer uterine steroid metabolism in reproductive seasons. Blood and uteri (endometrium and myometrium) were collected post mortem from hinds on 4th day (N = 8), 13th day of the cycle (N = 8), anestrus (N = 8) and pregnancy (N = 8). The expression of cytochrome P450 aromatase (P450), 3 -beta-hydroxysteroid dehydrogenase (3β-HSD), 17 -beta-hydroxysteroid dehydrogenase (17β-HSD), aldo–keto reductase family 1 C1 (AKR1C1), estrogen receptor alpha (ERα), and progesterone receptors (PRs), were analyzed using real-time-PCR and Western Blotting. Plasma samples were assayed for 17-beta-estradiol (E2), progesterone (P4), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone (T4) concentrations by EIA. Hinds at the beginning of the estrous cycle, mainly in endometrium, were characterized by a high mRNA expression of 3β-HSD, AKR1C1, PRs and ERα, contrary to the expression in myometrium during pregnancy (P < 0.05). For P4, E2, and FSH, concentration was the highest during the 13th day of the estrous cycle (P < 0.05). Uterine steroid production and output in hinds as a representative seasonally reproduced ruminant occurred mainly during the estrous cycle and sustained in anestrus.

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“…A previous study indicate that J-Synch protocol produces late ovulation (28 hours apart), increases dominant follicle growth rate, with higher concentration of progesterone between days 6 and 12 post ovulation and a mature uterine environment (lower proportion of progesterone receptors) (de la Mata et al, 2018). Therefore, an improvement in the fertility was obtained in artificially inseminated females after generating prolonged proestrus (de la Mata et al, 2015;Menchaca et al, 2014;Macmillan et al, 2020;Núñez-Olivera et al, 2020). Recent studies carried out with Angus, Simmental, Simangus, and Hereford heifers (Bó et al, 2018;de la Mata et al, 2015; and on heifers and cross Angus and Simmental cows (McMillan et al, 2020) with body condition score higher than 3 (scale 1 to 5), obtained higher pregnancy rates after J-Synch protocol than Conventional.…”

Section: Discussionmentioning

confidence: 99%

“…Previous research suggest that, the administration of eCG stimulates the growth of the dominant follicle and therefore the pregnancy rate (Bó et al, 2016(Bó et al, , 2018. Moreover, some authors described pregnancy rate was enhanced by eCG treatment and the improvement was more evident when FTAI/GnRH was performed at 72 hours after device removal (de la Mata et al, 2018;Núñez-Olivera et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Pregnancy rate to FTAI in Braford heifers submitted to J-Synch protocol

Reineri¹,

Coria²,

Principi

et al. 2020

Med. Vet. (UFRPE)

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The objective of the present work was to evaluate the effect of J-Synch protocol on pregnancy rate (PR) of heifers artificially inseminated after detected estrus (DEAI) or at fixed-time (FTAI). Two hundred ninety-three Braford heifers were used. On day 0, all animals received 2.0 mg of estradiol benzoate administered intramuscularly (IM) and an intravaginal progesterone-releasing device (DIB, 0.5 g). Heifers were assigned to the following group: 1) J-Synch: on day 6, DIB devices were removed and 500 µg of d-Cloprostenol sodium (d-CS) was administered IM and paint was applied on tail base (tail-paint). On day 9 (60 h after DIB removal), heifers with ≥ 40% of the tail-paint rubbed off were inseminated. Those not showing estrus by 72 h after DIB removal received 100 µg of GnRH at that time and were FTAI. 2) Conventional: on day 7, DIB devices were removed, and 500 µg of d-CS and 0.5 mg of estradiol cypionate were administered IM and tail-paint. Fortyeight hours after DIB removal, heifers with the tail-paint rubbed off were DEAI. Those not showing estrus by 54 h after DIB removal were FTAI. Pregnancy rate was diagnosed by ultrasonography 30 days after FTAI in all heifers and did not differ between protocols (44.28% and 42.48%, P = 0.673). In both protocols, higher PR was observed in DEAI heifers (P = 0.047). In conclusion, the use of the J-Synch protocol generated similar PR to the Conventional protocol, allowing its use with the same efficiency. Furthermore, the DEAI generated better PR than the FTAI, regardless of the protocol used.

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Effect of equine chorionic gonadotropin (eCG) administration and proestrus length on ovarian response, uterine functionality and pregnancy rate in beef heifers inseminated at a fixed-time

Cited by 18 publications

References 32 publications

Factors associated with pregnancy rate in fixed-time embryo transfer in cattle under humid-tropical conditions of México

Factors associated with pregnancy rate in fixed-time embryo transfer in cattle under humid-tropical conditions of México

Regulation of uterine function during estrous cycle, anestrus phase and pregnancy by steroids in red deer (Cervus elaphus L.)

Pregnancy rate to FTAI in Braford heifers submitted to J-Synch protocol

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