Administration of a single dose of 300 IU of human chorionic gonadotropin seven days after the onset of estrus improves pregnancy rate in dairy goats by an unknown mechanism

Cortês, Luana Rangel; Souza-Fabjan, J. M. G.; Dias, D.S.; Martins, Bianca B.; Maia, A. L. R. S.; Veiga, M.O.; Arashiro, E. K. N.; Brandão, F. Z.; Oliveira, M. E. F.; Bartlewski, Pawel M.; Fonseca, J. F. da

doi:10.1016/j.domaniend.2020.106579

Cited by 10 publications

(19 citation statements)

References 48 publications

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“…In our study, no differences occurred regarding the EIR between hCG doses, similar to that observed in other studies evaluating the use of hCG upon embryo implantation [ 22 ]; yet, the administration of hCG enhanced other reproductive variables with respect to the use of GnRH and the control group [ 47 ]. Interestingly, in our study, the largest luteal area was observed in the G300-14 group, agreeing with a previous study evaluating 300 IU of hCG 7d post-estrus in Toggenburg goats under an intensive system (21° South), observing a positive relationship between luteal area and hCG dose [ 48 ]. Such a physiological scenario also coincides with other studies using different hCG doses in small ruminants under different production systems (i.e., extensive vs. intensive), across different years/seasons, and diverse latitudes, concluding that the use of hCG was able to induce estrous activity [ 11 , 15 , 16 , 49 , 50 ].…”

Section: Discussionsupporting

confidence: 93%

Luteogenesis and Embryo Implantation Are Enhanced by Exogenous hCG in Goats Subjected to an Out-of-Season Fixed-Time Artificial Insemination Protocol

Bustamante-Andrade

Meza-Herrera

Rodríguez-Martínez

et al. 2021

Biology

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The aim of this study was to evaluate the possible effect of two doses of hCG (100 and 300 IU) applied at two different times (7 and 14 d) after a fixed-time artificial insemination protocol (FTAI) upon some variables involved in the embryonic implantation rate in goats during the natural deep anestrous season (April, 25° north). The experimental units considered crossbred, multiparous, anovulatory goats (n = 69, Alpine, Saanen, Nubian x Criollo), with average body weight (43.6 ± 5.7 kg) and body condition score (1.86 ± 0.28 units) located in northern–semiarid Mexico (25° N, 103° W). Once the goat’s anestrus status was confirmed, goats were subjected to an estrus induction protocol. Upon estrus induction confirmation, goats (n = 61) were subjected to a FTAI procedure. Immediately after the FTAI, the goats were randomly distributed to five experimental groups: (1). G100-7 (n = 13) 100 IU, hCG 7 d post-FTAI, (2). G100-14 (n = 12) 100 IU hCG, 14 d post-FTAI, (3). G300-7 (n = 12) 300 IU, hCG, 7 d post-FTAI, (4). G300-14 (n = 12) 300 IU hCG 14 d post-FTAI, and (5). Control group, CONT (n = 12) 0.5 mL saline, 7 and 14 d post-FTAI. The response variables conception rate (39.36 ± 0.23), fertility rate (27.96%), prolificacy rate (1.1 ± 0.29 kids), ovulation rate (0.74 ± 0.20 corpus luteum) corpus luteum diameter (10.15 ± 0.59 mm), embryo number (1.58 ± 0.20), and embryo implantation rate (48.96%), did not differ between treatments. However, while the variables fecundity rate (67%), embryo efficiency index-1 (33.99 ± 0.20%), and embryo efficiency index-2 (27.94 ± 0.30%) were favored by the G300-14 treatment, the corpus luteum area was favored (p < 0.05) by both G300-7 (113.30 ± 0.19 mm2) and G300-14 (103.04 ± 0.17 mm2). Such reproductive strategy emerges as an interesting approach, not only to enhance the out-of-season reproductive outcomes, but also to boost one of the main rulers defining the global reproductive efficiency of a heard, namely, the embryo implantation efficiency.

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Section: Discussionsupporting

confidence: 93%

Luteogenesis and Embryo Implantation Are Enhanced by Exogenous hCG in Goats Subjected to an Out-of-Season Fixed-Time Artificial Insemination Protocol

Bustamante-Andrade

Meza-Herrera

Rodríguez-Martínez

et al. 2021

Biology

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“…The diameter and position of all detected luteal structures were sketched on individual ovarian charts. B‐mode images were used to measure the total luteal area (cm 2 ), defined as the sum of cross‐sectional areas of all detected luteal structures; the areas of central cavities, if present, were subtracted from the total luteal area (Côrtes et al, 2021). The Doppler area (DA) of each luteal structure and high‐velocity DA (HVDA) were then determined using ImageProPlus® analytical software (Media Cybernetics Inc., San Diego, CA, USA).…”

Section: Methodsmentioning

confidence: 99%

“…Transrectal ovarian ultrasonography (B-mode and colour Doppler) was conducted 1 week before the beginning of oestrus synchronization to confirm the cyclicity of goats (presence of CL) and on days 3, 7, 10, 13, 17 and 21 (day 0 = day of FTAI), using a portable ultrasound scanner connected to a 7.5-MHz transducer (M5 Vet®; Mindray Medical International Limited, Shenzhen, China; Figure 1). images were used to measure the total luteal area (cm 2 ), defined as the sum of cross-sectional areas of all detected luteal structures; the areas of central cavities, if present, were subtracted from the total luteal area (Côrtes et al, 2021). The Doppler area (DA) of each luteal structure and high-velocity DA (HVDA) were then determined using ImageProPlus® analytical software (Media Cybernetics Inc., San Diego, CA, USA).…”

Section: Ultrasonographic Assessmentsmentioning

confidence: 99%

“…Human chorionic gonadotropin (hCG) has been used to improve the reproductive efficiency of small ruminants (da Fonseca et al, 2021). Administered in the presence of functional ovulatory corpora lutea (CL), hCG induces the formation of accessory CL (Côrtes et al, 2021; Fonseca et al, 2018; Rodrigues et al, 2022; Vergani et al, 2020), has a luteotropic effect on original CL, increases circulating progesterone (P 4 ) concentrations (Fonseca et al, 2006; Rodrigues et al, 2022; Vergani et al, 2020) and boosts pregnancy rates in small ruminants (Akif Cam & Kuran, 2004; Côrtes et al, 2021; Gómez‐Brunet et al, 2007; Khan et al, 2009; Rodrigues et al, 2022). Human chorionic gonadotropin can also be used at the time of mating/artificial insemination.…”

Section: Introductionmentioning

confidence: 99%

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Luteal function in cyclic goats treated with human chorionic gonadotropin administered by intramuscular or intravaginal routes at the time of artificial insemination

Rodrigues

Guimarães

Rangel

et al. 2022

Reprod Domestic Animals

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Human chorionic gonadotropin (hCG) has been used to improve goats reproductive efficiency. This study aimed to (i) evaluate if hCG administered by the intramuscular (i.m.) or intravaginal (i.vag.) route can be detected by a rapid β-hCG test in blood plasma samples and (ii) document ovarian effects of hCG administered by both routes at the time of artificial insemination (AI) performed 60 h after oestrus synchronization in goats. Twenty-two Alpine goats received two i.m. injections of 30 μg of dcloprostenol (Prolise®, Tecnopec, São Paulo, Brazil) 7.5 days apart. One day after the onset of oestrus (at the time of AI), the goats were randomly allocated to one of the three groups that received: control (n = 7): 0.3 ml of saline solution intravaginally; hCG i.m. (n = 7): 300 IU of hCG (Vetecor®; Hertape-Calier, São Paulo, Brazil) i.m. and hCG i.vag. (n = 8): 300 IU of hCG deposited intravaginally. Blood samples were drawn at −1, 3, 6, 9 and 24 h after as well as on days 3, 7, 10, 13, 17 and 21 after hCG treatment/ AI. All animals tested negative for hCG (ECO Diagnóstica, Corinto, Brazil) at −1 h, and all control animals tested negative throughout the entire blood collection period. All hCG i.m. animals tested positive from 3 h until D3 post-AI but only 50% of hCG i.vag.goats tested positive during the present study. In all animals studied, mean circulating P 4 concentrations increased (p < .05) from D3 to D7 after AI and then declined (p < .05) from D10 to D17 in control and hCG i.m. groups and from D17 to D21 in the hCG i.vag. group. Total cross-sectional luteal area (CLA), mean colour Doppler area (DA), DA/ CLA, mean high-velocity Doppler area and HVDA/CLA all declined (p < .05) by D17-D21 in all animals studied. In summary: (i) human chorionic gonadotropin could consistently be detected in blood samples using the rapid β-hCG test only in the hCG i.m. group; and (ii) there were no significant differences in the mean pregnancy rate, circulating P 4 concentrations and various luteal parameters studied among Control, hCG i.m. and hCG i.vag. dose.

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“…Despite this, it is important to emphasize the positive effects that hCG can exert directly on the embryo. These effects are associated with an increase in P4 secretion, promoting an improvement in uterine function and, consequently, an increase in fertility (Côrtes et al, 2021). The luteal-enhancing action of hCG may allow a healthier P4 supplementation compared with exogenous P4 supplementation.…”

Section: Discussionmentioning

confidence: 99%

Strategies to improve cervical relaxation, ovarian response, and embryo yield in sheep undergoing non-surgical embryo recovery

Dias¹

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Multiple ovulation and embryo transfer (MOET) play a key role in accelerating sheep farming, but it is still limited by obstacles such as embryo recovery technique and variability in the superovulatory (SOV) response. This study evaluates alternatives to these limitations, aiming to increase in vivo embryo production in sheep. The first chapter reviews some relevant points of non-surgical embryo recovery (NSER): ovine cervical anatomy, physiological mechanisms of cervical relaxation, and current cervical relaxation protocols (PRC). The second and third chapters evaluate the efficiency of PRC using zero (0.0mg), half (0.5mg), or full dose (1.0mg) of estradiol benzoate (EB) in synchronized and/or superovulated ewes and its effects on NSER feasibility and luteal function. Sheep were randomly assigned to receive 37.5 µg of d-cloprostenol i.m. and 0.0 mg (0EB group; n=12); 0.5 mg (0.5EB group; n=12) or 1.0 mg EB (1.0EB group, n=12) 16 h before and 50 IU oxytocin i.v. 20 minutes before the NSER. In synchronized sheep, NSER was performed in 91.7% (33/36) with a longer transposition duration with Hegar dilator and longer catheter-mandrel (P<0.05) in 0.0EB. The treatments did not differ (P>0.05) in the duration of uterine flushing or the rate of structure recovery. In superovulated ewes, there was no treatment or category effect (P>0.05) concerning NSER success. There was a reduction (P<0.05) in ovarian biometry and progesterone (P4) concentration and an increase in estradiol (E2) concentration on D17. The fourth chapter assesses the effectiveness of hCG administration after ovulation. Ovarian function, P4 profile, and embryo yield were evaluated. Superovulated ewes received 300 IU of hCG i.m. (GhCG, n=24) or not (GControl, n=25) 96 h after P4 removal. NSER efficiency, SOV response, and luteal tissue area were similar between groups (P>0.05). The hCG increased (P<0.05) P4 levels and tended to prevent structural luteolysis (P=0.07) but had no effect (P>0.05) on functional luteolysis. The fifth chapter studies the effect of 250, 333, or 400 IU of a commercial pFSH (1FSH: 1LH) on follicular growth, SOV response, and embryo yield. Superovulated ewes with decreasing doses of 250 (G250), 333 (G333), or 400 IU (G400) of pFSH were submitted to NSER. Estrus response, estrus interval, CL and LUF counts and follicular growth did not differ (P>0.05) between groups. The treatments did not differ (P>0.05) in embryo yield, but G333 and G400 showed a tendency (P=0.06) to have a higher mean of recovered structures compared to G250. This study concludes that: 1) NSER can be successfully performed in different sheep breeds, regardless of category, using a cervical relaxation protocol without estradiol benzoate; 2) the use or not of EB affected the luteal function, interfering mainly in estradiol levels; 3) hCG treatment increased circulating P4 before NSER and may prevent early luteal regression; 4) protocols using 250, 333 and 400 IU of pFSH are efficient in promoting follicular growth and superovulatory responses, but 333 IU appears to be more efficient in increasing embryo yield. Keywords: Biotechnologies. Embryos. MOET. Transcervical.

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Administration of a single dose of 300 IU of human chorionic gonadotropin seven days after the onset of estrus improves pregnancy rate in dairy goats by an unknown mechanism

Cited by 10 publications

References 48 publications

Luteogenesis and Embryo Implantation Are Enhanced by Exogenous hCG in Goats Subjected to an Out-of-Season Fixed-Time Artificial Insemination Protocol

Luteogenesis and Embryo Implantation Are Enhanced by Exogenous hCG in Goats Subjected to an Out-of-Season Fixed-Time Artificial Insemination Protocol

Luteal function in cyclic goats treated with human chorionic gonadotropin administered by intramuscular or intravaginal routes at the time of artificial insemination

Strategies to improve cervical relaxation, ovarian response, and embryo yield in sheep undergoing non-surgical embryo recovery

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