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The objective of this study was to evaluate the effect of embryo quality and developmental stages on pregnancy rate in beef heifer recipients. The present study used 168 Simmental breed cows as donors, and 618 beef cattle breed heifers as recipients. The quality and developmental stages of the collected embryos were evaluated according to the crite...
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Background
Currently, in vitro fertilization and embryo transfer (IVF-ET) typically involve transferring embryos on the third (D3) or fifth day (D5). However, a fresh cycle fourth day (D4) morula transfer offers a flexible and effective alternative. The compaction on the fourth day serves as a simple and reliable indicator to predict embryo implant...
In this study, the in vitro production of bovine embryos from zebu and taurine donors was compared. Cumulus-oocyte complexes (COCs) were obtained from 167 Bos taurus and 161 Bos indicus donors by ovum pick-up. COCs were classified based on their morphological quality, matured in incubators for 22 to 24 h in maturation medium, and then fertilized fo...
FET is to resuscitate the endometrium and transfer the embryo into the uterus after the endometrium is ready. The quality of transferred embryos is an important factor affecting the outcome of assisted reproductive technology. This paper aims to explore the feasibility of D4 frozen-thaw embryo transfer and analysis of related factors affecting the...
Objective: This study aims to investigate the impact of slow embryo development on the subsequent live birth rate and birthweight outcomes following a fresh day 5 transfer.
Study design: This retrospective multicenter cohort study included 1,213 consecutive patients undergoing autologous oocyte in vitro fertilization (IVF) treatment at four associa...
Linker histone variants regulate higher-order chromatin structure and various cellular processes. It has been suggested that linker histone variant H1a loosens chromatin structure and activates transcription. However, its role in early mouse development remains to be elucidated. We investigated the functions of H1a during preimplantation developmen...
Citations
... These factors include the nutritional status of the oocyte donor [9], environmental hygiene [10], infectious diseases [11], heat stress [12], and others. Taking care of embryo quality is of particular importance, as studies show that the highest success/pregnancy rate in cattle after embryo transfer (ET) can be reached if good quality embryos, mainly at the morula and blastocyst stage ( Fig. 1), are transferred [13][14][15][16]. In this regard, maternal age is a crucial factor, influencing the ET outcome and bornoffspring rate not only in cattle. ...
... To the best of the authors' knowledge, there is a paucity of scientific publications discussing the effect of cow age on embryonic development. Malhi et al. [20] conducted a study in which they collected embryos from old (13)(14)(15)(16) year-old) and young (3-6 year-old) cows. Their results showed that maternal aging affects the decrease in fertilization rate and the cleavage of mature and fertilized embryos in vivo in cattle. ...
In the first weeks after fertilization, embryo mortality in cattle is significantly higher. It is well known that the age of the dam is one of the crucial factors affecting the quality of embryos and oocytes in many mammalian species. In older cattle, there are several evidences that embryo quality decreases, due to a decrease in ovarian reserve, a decrease in mtDNA and ATP, a decrease in progesterone levels, and due to susceptibility to genetic mutations.
Herein, we intend to provide an updated summary of recent research on the effects of maternal age on embryos and oocytes of domestic cattle which are a widely used model species for human oocytes and early embryonic development.
... The EDS, EPM and embryo quality at the time of the transfer are other extrinsic factors affecting pregnancy rate in ET programs. Erdem et al. (2020) stated that the PR with excellent embryo quality were found to be higher compared with embryos of good quality. It was also determined that the embryonic developmental stages had no effect on PR during fresh embryo transfer in beef heifers. ...
Embryo transfer (ET) in bovines was created with the purpose of increasing the pregnancy rate (PR) of animals with high genetic value; however, multiple factors have been found to affect the success of this reproductive biotechnology. These factors are frequently grouped in intrinsic and extrinsic factors. Thus, the objective of the present experiments was to assess the effect of intrinsic and extrinsic factors on the pregnancy rate under tropical conditions. To do this a total of 648 embryo transfer (ET) procedures were performed between January and December 2021. The intrinsic factors were size and location of the corpus luteum, body condition, genetic group, age and parity; while extrinsic factors were location of the farm, environmental comfort, season in which the ET was carried out, prevailing weather conditions, and the preservation, quality, and the development stage of embryos at the time of ET. A χi² was used for analysis of main effects, and logistic regression analysis to calculate the probability of pregnancy and the association between intrinsic or extrinsic factors; additionally, a multivariate analysis of data clusters was used to find a linkage between the effects. While recipient female age had a negative effect (Odds ratio = 0.345—0.871) on PR (p < 0.05), being higher in younger cows, the rest of the intrinsic factors did not affect the PR. The significant (p < 0.05) extrinsic factors were THI category, season of year and type of embryo preservation, showing that the highest PR (p < 0.05) was obtained in the comfort THI category, during the winter season and using fresh embryos for transfer. The clustering analysis did not show any linkage between PR and intrinsic factors, while a linkage (p < 0.05) was found with season of the year and embryo preservation as extrinsic factors. It is concluded that age of the recipient cow and environmental conditions at the time of the embryo transfer are key factors to be considered for a successful pregnancy rate from in-vitro ET programs using dual-purpose cows under tropical conditions.
... Bó and Mapletoft (2013) stated that Grade 1 embryos have good survival rates after the freezing/thawing procedure, while Grade 2 and 3 embryos are more suitable for fresh transfer to appropriate recipients. Furthermore, Erdem et al. (2020) observed that Grade 1 embryos were associated with higher pregnancy rates during fresh embryo transfer than were Grade 2 embryos in heifers. ...
Avaliou-se o desenvolvimento pós-descongelamento de embriões bovinos produzidos in vitro (PIV) criopreservados pela técnica de vitrificação e de congelamento lento em diferentes dias após a fertilização in vitro (FIV). Foram realizadas 9 réplicas de PIV. Nos dias 7; 7,5 e 8 após a FIV, foram selecionados embriões no estágio de blastocisto expandido de grau de qualidade 1 e 2 (de acordo com o manual IETS). Os embriões (n=472) foram divididos aleatoriamente para serem criopreservados por congelamento lento (n=257) ou vitrificação (n=215). Organizou-se os embriões em 6 grupos de acordo com a técnica de criopreservação e o dia: 1) Grupo DT7 (embriões submetidos ao congelamento lento no D7, n= 140); 2) Grupo DT7,5 (embriões submetidos ao congelamento lento 12 horas após o D7, no D7,5; n= 61); 3) Grupo DT8 (embriões submetidos ao congelamento lento no D8, n=56); 4) Grupo VIT7 (embriões vitrificados no D7, n= 127); 5) Grupo VIT7,5 (embriões vitrificados 12 horas após o D7, no D7,5; n= 49); 6) Grupo VIT8 (embriões vitrificados no D8, n= 39). Os dados foram transformados para arcoseno e analisados por Análise de Variância utilizando o procedimento GLIMMIX do SAS (SAS 9.2) com P<0,05. A taxa de re-expansão e de eclosão embrionária foi maior para embriões vitrificados que para embriões submetidos ao congelamento lento (P<0,05). O grau de qualidade embrionária não influenciou as taxas de desenvolvimento totais (P>0,05). Porém embriões de grau 1 re-expandiram mais rapidamente (às 24 h) que embriões grau 2. Embriões grau 1 apresentaram melhores resultados com a técnica de vitrificação do que com congelamento lento. Os grupos experimentais representaram a interação técnica*dia e não diferiram entre si quanto as taxas de re-expansão e eclosão (P>0,05).
... Efforts in vitro embryo production focus on increasing BC1, since they have the greatest capacity to generate a pregnancy after being transferred [63] or survive cryopreservation [64]. In this study, the highest mean BC1 was observed in HH for both breeds, although without statistical differences ( Table 2). ...
... No effect of season or breed was observed on BC2 (Table 2),however, the means were very low, less than 0.8 ± 0.2. It is preferable to obtain BC1 and a smaller amount of BC2, since pregnancies are influenced by the quality of the blastocyst [63]. The increases in insulin in the donors decreased BC2, the high concentrations in the blood are related to the stress of the donors, since by reducing the entry of glucose into the cells, insulin concentrations increase as a mechanism protection and adaptation [69]. ...
One of the main factors that influence the fertility of cattle in grazing systems in hot tropical climates is heat stress. The objective of this study was to evaluate the effect of season, breed, hormonal and physiological condition on the quantity and quality of cumulus-oocyte complexes (COCs) and embryos produced in vitro, from Romosinuano (RM) and Tropical Milking (TM) donors. Three ovum pick-up and in vitro fertilization (OPU-IVF) were performed, one per season; hot dry (HD; 10, 10), hot humid (HH; 9, 9) and fresh dry (FD; 7, 10) in RM and LT donors. Serum levels of cortisol, insulin and glucose were measured, in addition to heart rate (HR), respiratory rate (RR) and rectal temperature (RT). Effect of season x genotype interaction (p≤0.05) was observed in all COCs variables and only in cleavage embryos (CLI) (p≤0.05). Body weight (BW) affected all COCs variables (p≤0.01), except unviable (UNV) although affected degenerated embryos (DEG) (p≤0.01) and total blastocysts (BLAST) (p≤0.01). Cow age only affected viable COCs (VIAB) (p ≤ 0.05), code one blastocysts (BC1) and BLAST (p≤0.01). Cortisol affected total COCs (COCsT), VIAB and total matured in vitro (TMIV) (p≤0.01), as well as CLI, BC1 (p≤0.01) and BLAST (p≤0.05). Insulin affected COCsT (p≤0.01), UNV (p≤0.05), denuded oocytes (DE) (p≤0.01), BC1 and code two blastocysts (BC2) (p≤0.01). Glucose affected all COCs variables (p≤0.01), except UNV and all embryo variables except BC2. HR affected COCsT, DE, TMIV (p≤0.01), CLI, BLAST and DEG (p≤0.05). RR affected COCsT, UNV, VIAB, CLI (p≤0.05), BC1, BLAST and DEG (p≤0.01). RT only affected DE, VIAB (p≤0.01) and BLAST (p≤0.05). The seasonal climatic year variation of Veracruz and changes in physiological and hormonal variables have diverse effects on the cumulus-oocyte complexes and embryos produced by RM and TM donors.
... The current study focused on metabolomic analysis exclusively in day 7 blastocysts of excellent quality (IETS Grade 1) for the initial validation of target metabolites, given that Grade 2 embryos yield lower pregnancy rates than Grade 1 embryos [50]. In field conditions, the transfer of Grade 2 embryos is feasible, albeit with diminished pregnancy outcomes [51]. In the dairy cattle industry, avoiding the transfer of Grade 2 embryos to lactating cow recipients is common, as these animals must achieve pregnancy shortly after calving to maximize economic returns, whereas transferring Grade 2 embryos to heifers is generally accepted [52]. ...
This study investigated whether metabolomic fingerprints of bovine embryo growth media improve the prediction of successful embryo implantation. In this prospective cohort study, the metabolome from in vitro-produced day 7 blastocysts with successful implantation (n = 11), blastocysts with failed implantation (n = 10), and plain culture media without embryos (n = 5) were included. Samples were analyzed using an AbsoluteIDQ® p180 Targeted Metabolomics Kit with LC-MS/MS, and a total of 189 metabolites were analyzed from each sample. Blastocysts that resulted in successful embryo implantation had significantly higher levels of methionine sulfoxide (p < 0.001), DOPA (p < 0.05), spermidine (p < 0.001), acetylcarnitine-to-free-carnitine ratio (p < 0.05), C2 + C3-to-free-carnitine ratio (p < 0.05), and lower levels of threonine (nep < 0.001) and phosphatidylcholine PC ae C30:0 (p < 0.001) compared to control media. However, when compared to embryos that failed to implant, only DOPA, spermidine, C2/C0, (C2 + C3)/C0, and PC ae C30:0 levels differentiated significantly. In summary, our study identifies a panel of differential metabolites in the culture media of bovine blastocysts that could act as potential biomarkers for the selection of viable blastocysts before embryo transfer.
... However, there was no significant difference between grades 1 and 2 (57% and 56% respectively) [1]. In Holstein cows, there was no difference in pregnancy rates between stages 4 to 7 and grades 1 and 2; however, in another study [15], cows with grade-1 embryos had a higher pregnancy rate than cows with grade-2 embryos, with no significant difference in pregnancy rates among different stages of grade-1 embryos. Heat shock (40℃)-exposed sperm were found to decrease embryonic development and the male ratio [16,17]. ...
... Grades 1-4 are assigned based on the characteristics of the zona pellucida, cytoplasmic regularity, and viability, with grades 1 and 2 considered suitable for embryo transfer [27]. This is consistent with previous findings reported by Phillips and Jahnke [27] and Erdem et al. [15], who observed a higher pregnancy rate with grade-1 than with grade-2 embryos. However, another study [1] reported no significant differences between grade-1 and grade-2 embryos. ...
... Pregnancy rates based on developmental stages of fresh and frozen embryos have not been extensively investigated in previous studies. Erdem et al. [15] reported that stages 5 and 6 exhibited the highest pregnancy rates, which aligns with the findings of Hasler [37] who observed the highest pregnancy rates at stage 5. However, contrasting results were reported by Putney et al. [38] and Ferraz et al. [24], who reported higher pregnancy rates in stage 7 and lower rates in stage 5. Vieira et al. [39] reported that the developmental stage of the embryo did not significantly affect pregnancy rates. ...
This study aimed to assess the effects of embryonic developmental stage, quality grade, and fresh or frozen/thawed conditions on the pregnancy rate and sex ratio of live offspring in Han-woo (Bos taurus coreanae) cows. The quality and developmental stage of in vivo-derived (IVD) transferred embryos were evaluated using the standard criteria of the International Embryo Technology Society. The recipient cows were synchronized using conventional (estradiol benzo-ate and progesterone) protocols before embryo transfer. Embryos were transferred to 297 cows, and pregnancy was monitored for 60-70 days after embryo transfer. The pregnancy rates of fresh and frozen/thawed embryos were 56.90% and 52.49%, respectively. Pregnancy rates varied according to embryo quality (56.18% for grade 1 vs. 36.67% for grade 2). Pregnancy rates also varied by developmental stage and cryopreservation (67.86% vs. 63.49% for stage 4-1, 64.00% vs. 54.72% for 5-1, and 50.00% vs. 47.83% for 6-1, in fresh embryos vs. frozen/thawed embryos, respectively). For stage 7-1, the pregnancy rates were 72.73% for fresh embryos and 20.00% for frozen/thawed embryos. In 66 fresh embryos, the sex ratio of live offspring was 5:5, whereas it was 4(female):6(male) for frozen/thawed embryos among the 95 frozen/thawed embryos. The miscarriage rate was approximately 3% higher for frozen/thawed embryos than for fresh embryos (18.1% for fresh vs. 21.1% for frozen). Seasonal fertility rates were 33.3% in spring, 55.67% in summer, 52.8% in autumn, 60.0% in winter. The following male-to-female ratios were observed in different seasons: 6.7:3.3 in spring, 4.0:6.0 in summer, 5.5:4.5 in autumn, and 3.3:6.7 in winter. The current data revealed no significant differences in pregnancy rates between fresh and frozen/thawed IVD embryos. However, there was a lower pregnancy rate with advanced-stage frozen/thawed embryos (stage 7-1). The current study provides comprehensive results for the better optimization of embryo transfer in Hanwoo cattle to obtain the desired fertility rate, pregnancy rate, and sex ratio of calves. These results provide important insights into the factors that influence the viability and success of IVD embryo transfer in Hanwoo cows and may have practical applications for improving breeding programs and reducing production costs.
... Notably, few numbers of second-and third-grade embryos were transferred during heat stress conditions. Similar results were reported previously regarding superior PR/ET after transfer of firstgrade embryos (Erdem et al., 2020;Ferraz et al., 2016). It is likely that first-grade embryos have greater developmental potential after F I G U R E 5 Effect of heat stress (THI ≥ 73)* versus embryo stage on PR/ET in recipient dairy heifers. ...
... Although not significant, this finding is in accordance with those from previous studies (Baruselli et al., 2020;Erdem et al., 2020) (Arreseigor et al., 2016;Looney et al., 2006). ...
This study aimed to determine effects of exposure of recipient dairy heifers to heat stress (THI≥ 73) during the estrous cycle coinciding with embryo transfer (ET) on the risk of pregnancy establishment after transfer of in vivo produced embryos. Recipients exposed to THI values ≥ 73 during days zero (recipient estrus), 7 (day of ET), 14 (seven days after ET), 15 and 16 (maternal recognition of pregnancy) of the ET cycle were considered as heat stressed heifers (n=254), while heifers in the control group (n=470) were not exposed to THI≥ 73 at any of the previous days. Results revealed no significant effects of any of the investigated factors on the risk of pregnancy following ET. However, the mean THI above 77 was associated with a drastic numerical decrease in PR/ET (36.63%), when compared to a mean THI 72 (78.78%). In addition, PR/ET after transfer of second and third grade embryos were numerically lower in heat‐stressed recipients, compared to first grade embryos (41.17 vs 56.36%, respectively). Our findings confirmed that transfer of blastocysts were associated with numerically higher PR/ET in heat stressed and control recipients, as compared to morula stage. Interestingly, PR/ET tended to be higher when sexed embryos were transferred to the control recipients compared to heat‐stressed ones. In conclusion, PR/ET in dairy heifers was not significantly affected by heat stress during critical windows of their estrous cycle coinciding with ET, whereas transfer of sexed embryos gives lower results under conditions of heat stress.
... In previous pilot assays, the total dose was adjusted in order to avoid an overstimulation due to the bscrFSH purity grade. Moreover, slightly different doses of bscrFSH or slight adjustments in the timing of procedures, e.g., modifications in the timing of CIDR removal or even an increase from a 4-day FSH to a 5-day FSH SOV protocol or even more, might result in a higher yield of blastocysts in comparison to morulae [56,70]. ...
Over the last few years, several commercial FSH products have been developed for cattle superovulation (SOV) purposes in Multiple Ovulation and Embryo Transfer (MOET) programs. The SOV response is highly variable among individuals and remains one of the main limiting factors in obtaining a profitable number of transferable embryos. In this study, follicle stimulating hormone (FSH) from different origins was included in two SOV protocols, (a) FSH from purified pig pituitary extract (NIH-FSH-p; two doses/day, 12 h apart, four consecutive days); and (b) extra-long-acting bovine recombinant FSH (bscrFSH; a single dose/day, four consecutive days), to test the effects of bscrFSH on the ovarian response, hormone profile levels, in vivo embryo production and the pluripotency gene expression of the obtained embryos. A total of 68 healthy primiparous red Angus cows (Bos taurus) were randomly distributed into two experimental groups (n = 34 each). Blood sample collection for progesterone (P4) and cortisol (C) level determination was performed together with ultrasonographic assessment for ovarian size, follicles (FL) and corpora lutea (CL) quantification in each SOV protocol (Day 0, 4, 8, and 15). Moreover, FSH profiles were monitorised throughout both protocols (Day 0, 4, 5, 6, 7, 8, 9, 10, and 15). In vivo embryo quantity and quality (total structures, morulae, blastocysts, viable, degenerated and blocked embryos) were recorded in each SOV protocol. Finally, embryo quality in both protocols was assessed by the analysis of the expression level of crucial genes for early embryo development (OCT4, IFNt, CDX2, BCL2, and BAX). P4 and cortisol concentration peaks in both SOV protocols were obtained on Day 15 and Day 8, respectively, which were statistically different compared to the other time-points (p < 0.05). Ovarian dimensions increased from Day 0 to Day 15 irrespective of the SOV protocol considered (p < 0.05). Significant changes in CL number were observed over time till Day 15 irrespective of the SOV protocol applied (p < 0.05), being non- significantly different between SOV protocols within each time-point (p > 0.05). The number of CL was higher on Day 15 in the bscrFSH group compared to the NIH-FSH-p group (p < 0.05). The number of embryonic structures recovered was higher in the bscrFSH group (p = 0.025), probably as a result of a tendency towards a greater number of follicles developed compared to the NIH-FSH-p group. IFNt and BAX were overexpressed in embryos from the bscrFSH group (p < 0.05), with a fold change of 16 and 1.3, respectively. However, no statistical differences were detected regarding the OCT4, CDX2, BCL2, and BCL2/BAX expression ratio (p > 0.05). In conclusion, including bscrFSH in SOV protocols could be an important alternative by reducing the number of applications and offering an improved ovarian response together with better embryo quality and superior performance in embryo production compared to NIH-FSH-p SOV protocols.
... In previous pilot assays, the total dose was adjusted in order to avoid an overstimulation due to the bscrFSH purity grade. Moreover, slightly different doses of bscrFSH or slight adjustments in the timing of procedures, e.g., modifications in the timing of CIDR removal or even an increase from a 4-day FSH to a 5-day FSH SOV protocol or even more, might result in a higher yield of blastocysts in comparison to morulae [56,70]. ...
... In previous pilot assays, the total dose was adjusted in order to avoid an overstimulation due to the bscrFSH purity grade. Moreover, slightly different doses of bscrFSH or slight adjustments in the timing of procedures, e.g., modifications in the timing of CIDR removal or even an increase from a 4-day FSH to a 5-day FSH SOV protocol or even more, might result in a higher yield of blastocysts in comparison to morulae [56,70]. ...
