What is an early blastocyst? (And does it matter?)

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Published on: January 3, 2020

Written by Dr. Jennifer Barfield

This year at the annual AETA/CETA meeting in Colorado Springs approximately 100 people signed up for a pre-conference symposium on Advanced ET. One of the three sessions was embryo grading where the audience was asked to stage and grade a variety of embryos from both pictures and videos. This is an exercise that we have done at this meeting in the past and it was interesting to revisit some of the same questions. As in the past, I polled the participants in this session to gauge what level of expertise was in the audience. The breakdown according to years of experience was 0-5 (25%), 6-10 (19%), 11-15 (12%), 16-20 (12%), and 21+ (32%).

For many of the questions the results showed a general consensus, but there was one question for which the distribution was not what I expected. The slide below is the question as it was presented to the audience. The embryo photo is from the IETS Bovine In Vivo Ova Tutorial (see p. 85, IETS members can access the document here https://www.iets.org/pubs_educational.asp).

Across all 3 sessions the answers were A 7%, B 54%, C 34%, D 1%, and E 4% with more disagreement in the first and third session than in the second. See Figure 2. In all sessions more people classified this embryo as an early blastocyst but the number of people who classified this a full blastocyst surprised me. I went back to look at the IETS guide and it stated that as the blastocoele of this embryo is approaching 50% of the embryo that this may be considered a stage 6 embryo.

As someone who often teaches students about classifying and grading embryos, the idea that I may have been instructing people incorrectly troubled me. At Colorado State University, I teach that an early blastocyst is one in which there is a blastocoele cavity present that has not yet filled the perivitelline space of the embryo, even if the blastocoele cavity is larger than 50% of the embryo. A full blastocyst is characterized by a blastocoele cavity that touches the zona pellucida on all sides, except for where it touches the inner cell mass, thus there is no PV space. I wondered if perhaps my interpretation of an early blastocyst is the result of a drift in teaching from an earlier time when these definitions were more strictly and/or widely followed. So I broke down the answers for this question according to years of experience thinking that perhaps practitioners who were learning how to classify embryos when the guidelines were developed would adhere to them more strictly, i.e. more often calling an embryo like this a full blastocyst. That wasn’t the case.

Of the respondents who had over 20 years of experience, 69% classified this embryo as an early blastocyst (24/35) while 52% of the youngest cohort classified this embryo as early (14/27). The only group in which more people called this a blastocyst than an early blastocyst was the 11-15 years group, although there were few respondents overall in this group (8/13 called this a blastocyst). So, I was wrong about the oldest yet wisest of us following the IETS staging guidelines more strictly.

That led me to ask the question, does it even matter if we are all calling this embryo an early blastocyst or a blastocyst? If you are collecting and transferring day 7 in vivo-produced embryos, probably not. The pregnancy rates from transferring grade 1 early blastocysts and grade 1 blastocysts are not significantly different (Hasler, 2001). This slight difference in stage would not change the synchrony of the recipient you choose. It would likely not change how you would cryopreserve this embryo as most in vivo embryos are slow frozen rather than vitrified. From a research standpoint we often make distinctions in stage depending on the question being asked, so it’s possible that inconsistencies in classifying embryos in the field could yield some erroneous conclusions, although I’ll admit I cannot give you any examples of this as I have not scoured the literature for papers where there were significant differences in outcome between early blastocysts and blastocysts for any tested hypothesis.

Outside of simply desiring consistency, the only time when the decision to call it an early blastocyst verses a blastocyst may be important is when grading in vitro-produced embryos. Grading embryos is not only based on the physical appearance of the embryo but also on its stage of development. The slide below was also discussed during the embryo grading sessions in the context of how to incorporate stage into overall embryo grade. In vitro-produced embryos are approximately 1 day more advanced in development than in vivo-produced embryos because of what we consider day 0 in these 2 systems (in vivo day 0 = standing heat, in vitro day 0 = initiation of co-incubation of sperm and oocytes). All morulae would be a day behind in development in an IVP system and given a grade 2 no matter how perfect but early blastocysts sit on the fence. Grading may be an instance where the > or < 50% blastocoele volume distinction matters with embryos with <50% of the volume being the blastocoele cavity being grade 2 and those with >50% volume being blastocoele grade 1. Still, I would be surprised if this fine distinction and difference in grade would translate into a significant difference in pregnancy rates, which is what matters. If anyone has data that may provide insight, please share it! 

So does it matter if we are all calling this small subset of embryos early blastocysts or blastocysts? Probably not, at least not for in-vivo produced embryos. Is it interesting? I think so, particularly from an educational and research perspective. Is it something that we as a community of reproductive practitioners and embryologists should talk more about as we consider developing a separate grading system for in vitro-produced embryos? I’d say yes.

How much Follicle Stimulating Hormone do we really need for cattle superovulation ?

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Published on: January 3, 2020

Superovulation data

Although the American Embryo Transfer Association and the International Embryo Technology Society perform a tremendous and necessary review of embryo transfer activity in the United States (Tables 1 and 2) and worldwide, there are limited data available on the dose, type, route of delivery, and protocols for Follicle Stimulating Hormone (FSH) administration (Kelly, 1997).  Other factors that contribute to the success of ovarian hyperstimulation are the breed, age, parity, and management of cattle, ovarian follicular reserve, and superovulation history of a particular donor.  Delivery of FSH to achieve superovulation is generally a twice daily injection schedule beginning on the day before or the day of emergence of a follicular wave (Adams, 1992) and lasting for three or four days; however, single dose (Looney, 1986; Bo, 1994; Kelly, 1997) or split single dose delivery (Tribulo, 2012), as well as FSH gels (Kimura, 2016) and implants (Floyd, 2007) to enhance bioavailability have been reported.  The current FDA approved FSH product is a pituitary derivative although the interest in producing a custom, reliable, and effective, FSH (and Luteinizing Hormone [LH]) product from recombinant technology has a substantial history (Looney, 1988; Wilson, 1993) and is gaining considerable traction (Hesser, 2011; Vega, 2019).  Classically, pituitary-derived FSH products had substantial LH contamination and a role for each of the gonadotropins was hypothesized (Donaldson, 1985).  The current product is very pure although it is likely that some LH might well be important for successful nourishment of multiple dominant follicles (Ginther, 1996) although it may be difficult to mimic the pulsatile pattern of LH.  Regardless of the protocol, the most critical component for FSH administration is the timing relative to the endogenous FSH surge.  Practically, this approach requires a hormonal or mechanical technique to engineer a follicular wave in order to efficiently schedule the embryo collection (Crowe, 2013.  The protocol for engineering a follicular wave also has many considerations and challenges (time, expensive equipment, choice of hormones, etc.).

What if we miss an FSH injection?

The literature is scant with information about which FSH injections are the most important.  It seems logical that the first few injections are the most important (due to dosage and timing) and the last few are the least important.  Using a six FSH injection protocol following ultrasound guided follicular ablation of all follicles larger than 5 mm, the administration of the sixth FSH injection or not did not impact the embryo recovery results (Gibbons, 2019).  Practically, even if it is known that an FSH injection was missed, the donor will still likely be inseminated and embryo recovery attempted.  A single dose of FSH administered on Day 10 following estrus has been shown to produce a similar number of ovulations as a multi-dose approach (Kelly, 1997); however, there were more degenerate embryos and unfertilized ova, suggesting that in addition the scheduling aspect, engineering a follicular wave for superovulation may be important impact the “fertilizability” of the ova within the follicles and the timing of the first few FSH injections relative to follicular wave emergence outweighs the effects of any other single FSH injection.

FSH per Transferable Embryo

There is no public data base for the amount of FSH given to any one donor.  There are recent data (Gibbons, 2019) to suggest that the amount of FSH per transferable embryo may be as low as 1.5 mls (54 IU; Folltropin) following an engineered follicular wave.  The appropriate timing of FSH initiation could decrease the overall required dosage of FSH, which is financially important given that the cost of FSH is one of the largest single costs associated with superovulation.  Further, although there is a relatively accurate idea of how many corpora lutea (CL) are present at embryo collection, without counting the CL via ultrasonography, it is difficult to know if or how many embryos / ova are not accounted for following collection. 

Where do we go from here?

In vitro embryo technologies are clearly gaining considerable traction (Table 2.); however, the need for effective and efficient superovulation protocols remains important.  The effectiveness of these protocols is linked to the timing of the initial FSH injection; however, due to the considerable number of different protocols that are available it is difficult to determine which approach more appropriately exploits the endogenous FSH surge and results in more transferable embryos.  Future research comparing different FSH protocols relative to endogenous FSH profiles and follicular wave emergence will be important and may increase the number of transferable embryos per collection which has not waivered substantially in 20 plus years.

References:

Adams GP, Matteri RL, Kastelic JP, Ko JC, Ginther OJ.  Association between surges of follicle-stimulating hormone and the emergence of follicular waves in heifers.  Journal of Reproduction Fertility, 1992; 94(1):177-188.

Bo GA, Hockley DK, Nasser LF, Mapletoft RJ.  Superovulatory response to a single subcutaneous injection of Folltropin-V in beef cattle.  Theriogenology, 1994;42(6):963-975.

Crowe MA, Mullen MP.  Relative roles of FSH and LH in stimulation of effective follicular response in cattle.  Intech Open Access, 2013; http://dx.doi.org/10.5772/50272.

Donaldson LE.  LH and FSH at superovulation and embryo production in the cow.  Theriogenology 1985;23(3):441-447.

Floyd C.  Subcutaneous FSH implants.  MS Thesis, Clemson University, 2007: https://tigerprints.clemosn.edu/all_thesis/94.

Gibbons JR, Anton J.  Dominant follicle removal prior to superovulation.  Poster presented at 2019 joint annual AETA & CETA/ACTE convention, 2019.

Ginther OJ, Wiltbank MC, Fricke PM, Gibbons JR, Kot K.  Selection of the dominant follicle in cattle.  Biology of Reproduction 1996;55:1187-1194.

Hesser MW, Morris JC, Gibbons JR.  Advances in recombinant gonadotropin production for use in bovine superovulation.  Reproduction Domestic Animals, 2011;46:933-942.

Kelly P, Duffy P, Roche JF, Boland MP.  Superovulation in cattle: effect of FSH type and method of administration on follicular growth, ovulatory response and endocrine patterns.  Assisted Reproduction Sciences 1997;46:1-14.

Kimura K.  Superovulation with a single administration of FSH in aluminum hydroxide gel: a novel superovulation method for cattle.  Journal of Reproduction Development, 2016;62(5):423-429.

Looney CR, Bondioli KR, Hill KG, Massey JM.  Superovulation of donor cows with bovine follicle-stimulating hormone (bFSH) produced by recombinant DNA technology.  Theriogenology 1988;29:271.

Looney CR.  Superovulation in beef females.  Proceedings of the 5th annual conference of American Embryo Transfer Association, 1986;16-29.

Tribulo A, Rogan D, Tribulo H, Tribulo R, Mapltoft RJ, Bo GA. 

Superovulation of beef cattle with a split-dose intramuscular administration of Folltropin-V in two concentrations of hyaluronan.  Theriogenology 2012;77:1679-1685.

Vega VMB, Chavez SPJ, Franco CDM, Ramos TI, Toledo JR.  FSH in superovulation.  Revista Bionature, 2019;812-816.

Wilson JM, Jones AL, Moore K, Looney CR, Bondioli KR.  Superovulation of cattle with a recombinant-DNA bovine follicle stimulating hormone.  Animal Reproduction Science, 1993;33(1):71-82.

Articles of Interest

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Published on: January 3, 2020

The pre-hatching bovine embryo transforms the uterine luminal metabolite composition in vivo

Somatic cell nuclear transfer alters peri-implantation trophoblast differentiation in bovine embryos

Placental development during early pregnancy in sheep: Effects of embryo origin on vascularization

Bovine Fetal Placenta During Pregnancy and the Postpartum Period

Heifer nutrition during early- and mid-pregnancy alters fetal growth trajectory and birth weight

Reduced quality of bovine embryos cultured in media conditioned by exposure to an inflamed endometrium

Pivotal periods for pregnancy loss during the first trimester of gestation in lactating dairy cows

Evaluation of the uterine environment early in pregnancy establishment to characterise cows with a potentially superior ability to support conceptus survival

Preliminary trials of a specific gravity technique in the determination of early embryo growth potential†

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Published on: July 26, 2019

Read full article here

S.D. Prien,1,2,* C.E. Wessels,2 and L.L. Penrose1

. 2015 Sep; 30(9): 2076–2083.
Published online 2015 Jul 22. doi: 10.1093/humrep/dev178
PMCID: PMC4542720
PMID: 26202920

Abstract

STUDY QUESTION

Can a modified specific gravity technique be used to distinguish viable from nonviable embryos?

SUMMARY ANSWER

Preliminary data suggests a modified specific gravity technique can be used to determine embryo viability and potential for future development.

WHAT IS KNOWN ALREADY

Single embryo transfer (SET) is fast becoming the standard of practice. However, there is currently no reliable method to ensure development of the embryo transferred.

STUDY DESIGN, SIZE, DURATION

A preliminary, animal-based in vitro study of specific gravity as a predictor of embryo development using a mouse model.

PARTICIPANTS/MATERIALS, SETTING, METHODS

After a brief study to demonstrate embryo recovery, experiments were conducted to assess the ability of the specific gravity system (SGS) to distinguish between viable and nonviable embryos. In the first study, 1-cell mouse embryos were exposed to the SGS with or without previous exposure to an extreme heat source (60°C); measurements were repeated daily for 5 days. In the second experiment, larger pools of 1-cell embryos were either placed directly in culture or passed through the SGS and then placed in culture and monitored for 4 days.

MAIN RESULTS AND THE ROLE OF CHANCE

In the first experiment, viable embryos demonstrated a predictable pattern of descent time over the first 48 h of development (similar to previous experience with the SGS), while embryos that were heat killed demonstrated significantly altered drop patterns (P < 0.001); first descending faster. In the second experiment, average descent times were different for embryos that stalled early versus those that developed to blastocyst (P < 0.001). Interestingly, more embryos dropped through the SGS developed to blastocyst than the culture control (P < 0.01).

LIMITATIONS, REASONS FOR CAUTION

As this is a preliminary report of the SGS technology determining viability, a larger embryo population will be needed. Further, the current in vitro study will need to be followed by fecundity studies prior to application to a human population.

WIDER IMPLICATIONS OF THE FINDINGS

If proven, the SGS would provide a noninvasive means of assessing embryos prior to transfer after assisted reproductive technologies procedures, thereby improving fecundity and allowing more reliable SET.

STUDY FUNDING/COMPETING INTEREST(S)

The authors gratefully acknowledge the funding support of the U.S. Jersey Association, the Laura W. Bush Institute for Women’s Health and a Howard Hughes Medical Institute grant through the Undergraduate Science Education Program to Texas Tech University. None of the authors have any conflict of interest regarding this work.

TRIAL REGISTRATION NUMBER

none.

Keywords: embryo development, embryo selection, embryo viability, specific gravity, buoyance, noninvasive, zygote, blastocyst

In vitro culture systems: how far are we from optimal conditions?

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Published on: July 25, 2019

C. Wrenzycki

http://dx.doi.org/10.21451/1984-3143-AR869

Anim Reprod, vol.13, n3, p.279-282, 2016

Abstract

Over the past decades in vitro production (IVP) of bovine embryos has been significantly improved. Nevertheless, embryos generated in vitro still differ from their in vivo produced counterparts. Embryos must adjust to multiple microenvironments at preimplantation stages. Consequently, maintaining or mimicking the in vivo situation in vitro will aid to improve the quality and developmental competence of the resulting embryo.

cattle, embryo, in vitro production

Articles of Interest

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Published on: April 17, 2019

Significant heparin effect on bovine embryo development during sexed in vitro fertilization

Consequences of bovine oocyte maturation, fertilization or early embryo development in vitro versus in vivo: Implications for blastocyst yield and blastocyst quality

Sex control by Zfy siRNA in the dairy cattle

Daily administration of a GnRH analogue enhances sperm quality in bucks during the non-breeding season

Maternal age influences the number of primordial follicles in the ovaries of yearling Angus heifers

Role of cAMP modulator supplementations during oocyte in vitro maturation in domestic animals

Factors in cattle affecting embryo transfer pregnancies in recipient animals

Comparison of luteolysis and timed artificial insemination pregnancy rates after administration of PGF2α in the muscle or the ischiorectal fossa in cattle

Large-scale transcriptional analysis of bovine embryo biopsies in relation to pregnancy success after transfer to recipients

Effects of supplementation of medium with different antioxidants during in vitro maturation of bovine oocytes on subsequent embryo production

Influence of bovine serum albumin and fetal bovine serum supplementation during in vitro maturation on lipid and mitochondrial behaviour in oocytes and lipid accumulation in bovine embryos

50 Survival of sexed ivf-derived bovine embryos frozen at different preimplementation stages of development

141 Bovine embryo development rats are affected when oocytes are matured in different vials containing hepes/bicarbonate buffered medium

The ischiorectal fossa: an alternative route for the administration of prostaglandin in cattle

Effects of nutrition and genetics on fertility in dairy cows

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Published on: April 17, 2019

https://www.publish.csiro.au/RD/RD18364

Reproduction, Fertility and Development 31(1) 40-54 https://doi.org/10.1071/RD18364
Published online: 3 December 2018

Alex Bach

Institucio´Catalana de Recerca i Estudis Avanc¸ats (Barcelona 08007, Spain) and Department of Ruminant Production, Institut de Recerca i Tecnologies Agroalimenta`ries (Caldes de Montbui, 08140 Spain). Email: alex.bach@icrea.cat

Optimal reproductive function in dairy cattle is mandatory to maximise profits. Dairy production has progressively improved milk yields, but, until recently, the trend in reproductive performance has been the opposite. Nutrition, genetics, and epigenetics are important aspects affecting the reproductive performance of dairy cows. In terms of nutrition, the field has commonly fed high-energy diets to dairy cows during the 3 weeks before calving in an attempt to minimise postpartum metabolic upsets. However, in the recent years it has become clear that feeding high-energy diets during the dry period, especially as calving approaches, may be detrimental to cow health, or at least unnecessary because cows, at that time, have low energy requirements and sufficient intake capacity. After calving, dairy cows commonly experience a period of negative energy balance (NEB) characterised by low blood glucose and high non-esterified fatty acid (NEFA) concentrations. This has both direct and indirect effects on oocyte quality and survival. When oocytes are forced to depend highly on the use of energy resources derived from body reserves, mainly NEFA, their development is compromised due to a modification in mitochondrial b-oxidation. Furthermore, the indirect effect of NEB on reproduction is mediated by a hormonal (both metabolic and reproductive) environment. Some authors have attempted to overcome the NEB by providing the oocyte with external sources of energy via dietary fat. Conversely, fertility is affected by a large number of genes, each with small individual effects, and thus it is unlikely that the decline in reproductive function has been directly caused by genetic selection for milk yield per se. It is more likely that the decline is the consequence of a combination of homeorhetic mechanisms (giving priority to milk over other functions) and increased metabolic pressure (due to a shortage of nutrients) with increasing milk yields. Nevertheless, genetics is an important component of reproductive efficiency, and the incorporation of genomic information is allowing the detection of genetic defects, degree of inbreeding and specific single nucleotide polymorphisms directly associated with reproduction, providing pivotal information for genetic selection programs. Furthermore, focusing on improving bull fertility in gene selection programs may represent an interesting opportunity. Conversely, the reproductive function of a given cow depends on the interaction between her genetic background and her environment, which ultimately modulates gene expression. Among the mechanisms modulating gene expression, microRNAs (miRNAs) and epigenetics seem to be most relevant. Several miRNAs have been described to play active roles in both ovarian and testicular function, and epigenetic effects have been described as a consequence of the nutrient supply and hormonal signals to which the offspring was exposed at specific stages during development. For example, there are differences in the epigenome of cows born to heifers and those born to cows, and this epigenome seems to be sensitive to the availability of methyl donor compounds of the dam. Lastly, recent studies in other species have shown the relevance of paternal epigenetic marks, but this aspect has been, until now, largely overlooked in dairy cattle.

Additional keywords: Amino acids, Epigenetics, Fat, Glucose, Minerals, Reproduction, Vitamins

Antral follicle population in prepubertal and pubertal heifers

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Published on: April 17, 2019

https://www.publish.csiro.au/RD/RD18344

Reproduction, Fertility and Development 31(1) 10-16 https://doi.org/10.1071/RD18344
Published online: 3 December 2018

M. M. Seneda (A,D), F. Morotti (A), A. F. Zangirolamo (A,B), N. C. da Silva (A), K. Sanches (A), W. Blaschi (C), and T. R. R. Barreiros (C)

A Universidade Estadual de Londrina, Laborato´ rio de Reproduc¸a˜o Animal, Departamento de Clı´nicas Veterina´rias – Centro de Cieˆncias Agra´rias – Universidade Estadual de Londrina, Londrina, Parana, Brazil. B National Institute of Science and Technology for Dairy Production Chain (INCT–LEITE), Universidade Estadual de Londrina, Rodovia Celso Garcia Cid-Campus Universita´rio, PO Box 10011, Londrina, Parana 86057-970, Brazil. C Universidade Estadual do Norte do Parana´ , Laborato´ rio de Biotecnologia da Reproduc¸a˜o Animal, Departamento de Veterina´ria e Produc¸a˜o Animal, Rodovia BR – 369, Km 54, Vila Maria, Bandeirantes, Parana 86360-000, Brazil. D Corresponding author. Email: marcelo.seneda@uel.br

The antral follicle count (AFC) is an important tool in the selection of bovine females destined for biotechnology. However, little is known about AFC in prepubertal and pubertal heifers. Some challenges inherent to the physiology of young females must be considered to achieve efficient rates with different procedures, such as ovum pick-up and IVF. This paper covers some important topics about ovarian physiology related to the population of antral follicles and reproductive efficiency in young female cattle.

Additional keywords: Bos indicus, Bos taurus, calf, embryo production.

Cryopreservation and microfluidics: a focus on the oocyte

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Published on: April 17, 2019

https://www.publish.csiro.au/RD/RD18326

Reproduction, Fertility and Development 31(1) 93-104  https://doi.org/10.1071/RD18326
Published online: 3 December 2018

Gary D. Smith (A,C) and Shuichi Takayama (B)

A Departments of Obstetrics & Gynecology, Physiology, and Urology, Reproductive Sciences Program, University of Michigan, Ann Arbor, MI 48108, USA. B Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University School of Medicine, Atlanta, GA 30332, USA. C Corresponding author. Email: smithgd@umich.edu

Cryopreservation of gametes and embryos has played a critical role in successful assisted reproductive technologies in rodents, domestic farm species, endangered species and humans. With improved success, and changing needs, the utility of gamete or embryo cryopreservation has escalated. In this review we address some of the foundational history of mammalian cryobiology, species-specific utilities, fundamental understandings of cryoprotectant agents and their use in slow-rate freezing and vitrification, and expand on the recent success and uses of oocyte vitrification and warming. In the area of female gamete cryopreservation, emphasis will be placed on not just cell survival, but also perceived and measured affects of cryopreservation on intracellular structures and functions that affect subsequent completion of meiosis with chromatin segregation fidelity, normal fertilisation and embryonic developmental competence. We compare and contrast data from cow, mouse and humans with a focus on using species-comparative developmental biology to guide future studies for improving methodologies for all species. The application of the relatively new technology microfluidics is discussed in relation to moving gradually (i.e. changing the solution over cells in an automated fashion) compared with the stepwise manual movement of cells through changing solution currently used. This use of microfluidics to change the way cells are exposed to cryoprotectant agents can provide new insights into the effects of osmotic stress and cellular strain rates previously unappreciated, precise methods of computational and biological data acquisition and appreciation of morphometric changes to cellular structure in response to different osmotic stresses and strain rates achieved with varying cryoprotectant exposures. Collectively, these devices and methodologies provide a means of achieving incremental improvement of oocyte and zygote cryopreservation with normalised and improved developmental competence. Finally, we look to the past and the future to acknowledge the accomplishment of leaders in the field of mammalian gamete and embryo cryobiology, their inspirational works, their tireless dissemination of information and the potential of new technologies in bioengineering to improve the efficiency and safety of gamete and embryo cryopreservation.

Additional keywords: embryos, gametes, vitrification.

Articles of Interest

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Published on: December 27, 2018

Consequences of bovine oocyte maturation, fertilization or early embryo development in vitro versus in vivo: Implications for blastocyst yield and blastocyst quality

Cryopreservation of preimplantation embryos of cattle, sheep, and goats

A simple medium enables bovine embryos to be held for seven days at 4°C

Aggressive attempted escape behavior during head-lock restraint reduced reproductive performances in Holstein heifers

Effects of feeding a source of omega-3 fatty acid during the early postpartum period on the endocannabinoid system in the bovine endometrium

Relationships between numbers of antral follicles and postpartum interval in Brahman females

Administration of an herbal powder based on traditional Chinese veterinary medicine enhanced the fertility of Holstein dairy cows affected with retained placenta

Influence of cycle stage, age and endometrial biopsy score on oxytocin receptor distribution and gene expression in the cervix and uterus of non-pregnant mares

Comparison of pregnancy in cattle when non-vitrified and vitrified in vitro-derived embryos are transferred into recipients

 

Use of FSH in two different regimens for ovarian superstimulation prior to ovum pick up and in vitro embryo production in Holstein cows

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Published on: July 6, 2018

Authors: Júlio César Barboza da Silva, Roberta Machado Ferreira, Milton Maturana Filho, Julianne de Rezende Naves, Thiago Santin, Guilherme Pugliesi, Ed Hoffmann Madureira

Publication: Theriogenology

Publisher: Elsevier

Date of Publication: 1 March, 2017

Link: https://www.ncbi.nlm.nih.gov/pubmed/28166990

Superstimulation prior to the ovum pick-up to improve in vitro embryo production in lactating and non-lactating Holstein cows

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Published on: July 6, 2018

Authors: L.M. Vieira, C.A. Rodrigues, A. Castro Netto, B.M. Guerreiro, C.R.A. Silveira, R.J.C. Moreira, M.F. Sá Filho, G.A. Bó, R.J. Mapletoft, P.S. Baruselli

Publication: Theriogenology

Publisher: Elsevier

Date of Publication: 15 July 2014

Link: https://www.ncbi.nlm.nih.gov/pubmed/24839924

Short communication: Follicle superstimulation before ovum pick-up for in vitro embryo production in Holstein cows

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Published on: July 6, 2018

Authors: Louise H. Oliveira, Carlos P. Sanches,Adriano S. Seddon, Marcio B. Veras, Flávio A. Lima, Pedro L.J. Monteiro, Milo C. Wiltbank, Roberto Sartori

Publication: Journal of Dairy Science

Publisher: Elsevier

Date of Publication: November 2016

Link: https://www.journalofdairyscience.org/article/S0022-0302(16)30571-9/pdf

Articles of Interest

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Published on: July 6, 2018

In vitro sperm quality and DNA integrity of SexedULTRA sex-sorted sperm compared to non-sorted bovine sperm

 

Angiocoupling between the dominant follicle and corpus luteum during waves 1 and 2 in Bos taurus heifers

 

Improved uterine immune mediators in Holstein cows supplemented with rumen-protected methionine and discovery of neutrophil extracellular traps (NET)

 

Hormonal strategy to reduce suckled beef cow handling for timed artificial insemination with sex-sorted semen

 

Differential release of cell-signaling metabolites by male and female bovine embryos cultured in vitro

 

Synchronization treatments previous to natural breeding anticipate and improve the pregnancy rate of postpartum primiparous beef cows

 

Heat-shock-induced cathepsin B activity during IVF and culture compromises the developmental competence of bovine embryos

 

Associations between dairy cow inter-service interval and probability of conception

 

μ-Calpain (CAPN1), calpastatin (CAST), and growth hormone receptor (GHR) genetic effects on Angus beef heifer performance traits and reproduction

 

Assessment of the temperature cut-off point by a commercial intravaginal device to predict parturition in Piedmontese beef cows

 

Variations in bovine embryo production between individual donors for OPU-IVF are closely related to glutathione concentrations in oocytes during in vitro maturation

 

Eventual re-vitrification or storage in liquid nitrogen vapor does not jeopardize the practical handling and transport of vitrified pig embryos

 

Cryopreservation and in vitro culture of white-tailed deer ovarian tissue

 

Preparation, characterization and application of long-acting FSH analogs for assisted reproduction

 

Aromatase inhibitors: A new approach for controlling ovarian function in cattle

 

Pursuit of a method for single administration of pFSH for superstimulation in cattle: What we have learned

 

Progesterone-releasing devices for cattle estrus induction and synchronization: Device optimization to anticipate shorter treatment durations and new device developments

 

Potential of connected devices to optimize cattle reproduction

 

Vaginal temperature measurement by a wireless sensor for predicting the onset of calving in Japanese Black cows

 

Effect of different chorionic gonadotropins on final growth of the dominant follicle in Bos indicus cows

 

Effect of different shipping temperatures (∼22 °C vs. ∼7 °C) and holding media on blastocyst development after overnight holding of immature equine cumulus-oocyte complexes

 

A recovery time after warming restores mitochondrial function and improves developmental competence of vitrified ovine oocytes

 

Additional small dose of prostaglandin F at timed artificial insemination failed to improve pregnancy risk of lactating dairy cows

 

The relationship between external auditory canal temperature and onset of estrus and ovulation in beef heifers

 

Follicular response and oocyte production following variations in ovarian stimulation in goats

 

Inhibition of apoptosis by caspase inhibitor Z-VAD-FMK improves cryotolerance of in vitro derived bovine embryos

 

Promoter variants of OAS1 gene are associated with reproductive performance and incidence of normal calving in cattle

 

The ability to predict pregnancy loss in cattle with ELISAs that detect pregnancy associated glycoproteins is antibody dependent

 

http://www.sciencemag.org/news/2018/02/first-cow-embryonic-stem-cells-could-lead-healthier-more-productive-livestock

AETA Articles of Interest

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Published on: September 26, 2017

Birth of healthy calves after intra-follicular transfer (IFOT) of slaughterhouse derived immature bovine oocytes

Effects of oocytes exposure to bovine diarrhea viruses BVDV-1, BVDV-2 and Hobi-like virus on in vitro-produced bovine embryo development and viral infection

Relationship between in vitro growth of bovine oocytes and steroidogenesis of granulosa cells cultured in medium supplemented with bone morphogenetic protein-4 and follicle stimulating hormone

Equine chorionic gonadotropin increases fertility of grazing dairy cows that receive fixed-time artificial insemination in the early but not later postpartum period

Effective use of SexedULTRA™ sex-sorted semen for timed artificial insemination of beef heifers

Genetic component of sensitivity to heat stress for nonreturn rate of Brazilian Holstein cattle

Leptin supplementation in vitro improved developmental competence of buffalo oocytes and embryos

2-Methoxystypandrone improves in vitro-produced bovine embryo quality through inhibition of IKBKB

Split-time artificial insemination in beef cattle: III. Comparing fixed-time artificial insemination to split-time artificial insemination with delayed administration of GnRH in postpartum cows

Temporal effect of maternal heat stress during gestation on the fertility and anti-Müllerian hormone concentration of offspring in bovine

Maternal and non-maternal factors associated with late embryonic and early fetal losses in dairy cows

Blood flow and echotextural differences between the future dominant and subordinate follicles before the beginning of diameter deviation in heifers

Comparison of estrus synchronization by controlled internal drug release device (CIDR) and adhesive transdermal progestin patch in postpartum beef cows

Relationship among circulating anti-Müllerian hormone, insulin like growth factor 1, cadmium and superovulatory response in dairy cows

Follicular waves and hormonal profiles during the estrous cycle of carriers and non-carriers of the Trio allele, a major bovine gene for high ovulation and fecundity

Relationships between uterine health and metabolism in dairy cows with different dry period lengths

Insulin during in vitro oocyte maturation has an impact on development, mitochondria, and cytoskeleton in bovine day 8 blastocysts

Ovulation rate, antral follicle count, and circulating anti-Müllerian hormone in Trio allele carriers, a novel high fecundity bovine genotype

Evaluation of in vitro-produced bovine embryos

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Published on: June 30, 2017

2015 CETA/ACTE & AETA JOINT CONVENTION – NIAGARA FALLS, ONTARIO

SESSION: IVP vs IVD EMBRYO EVALUATION

Evaluation of in vitro-produced bovine embryos

Jennifer Barfield, Ph.D.

Animal Reproduction and Biotechnology Lab, Colorado State University, Fort Collins, CO

At the 2014 joint meeting of the American and Canadian Embryo Transfer Associations, I presented a pre-conference symposium on bovine embryo grading in an interactive forum where participants provided real-time feedback on how they would grade embryos of various stages and qualities. One aspect of grading touched on was the difference between in vitro-produced (IVP) and in vivo- derived (IVD) embryos. When asked whether the attendees believed we need separate grading systems for these two types of embryos, the crowd was split with 47% of respondents supporting the development of a new system and 53% believing it is not needed. Here I will review some of the challenges involved with grading IVP and IVD embryos, the implications of these challenges, and propose a method by which researchers and practitioners could collaborate to gather data that can be easily shared and used to develop a concensus on the best guidelines for grading IVP embryos.

(more…)

AETA Articles of Interest

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Published on: June 30, 2017

Relationship between circulating progesterone at timed-AI and fertility in dairy cows subjected to GnRH-based protocols

Lipid profiles of follicular fluid from cows submitted to ovarian superstimulation

Corrigendum to “Reducing treatments in cattle superovulation protocols by combining a pituitary extract with a 5% hyaluronan solution: Is it able to diminish activation of the hypothalamic pituitary adrenal axis compared to the traditional protocol?” [Theriogenology 85 (2016) 914–921]

Downsizing cumulus cell layers to improve cryotolerance of germinal vesicle-stage bovine oocytes

Evaluation of shortened timed-AI protocols for resynchronization of ovulation in multiparous Holstein dairy cows

Effects of rumen-protected methionine and choline supplementation on steroidogenic potential of the first postpartum dominant follicle and expression of immune mediators in Holstein cows

Effects of d-cloprostenol on different layers and regions of the bovine uterus during the follicular and luteal phases

Cryosurvival of in vitro produced bovine embryos supplemented with l-Carnitine and concurrent reduction of fatty acids

Articles of Interest

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Published on: March 21, 2017

Calving distributions of individual bulls in multiple-sire pastures

The effect of Presynch-Ovsynch protocol with or without estrus detection on reproductive performance by parity, and the long-term effect of these different management strategies on milk production, reproduction, health and survivability of dairy cows

Bacterial invasion of the uterus and oviducts in bovine pyometra

Transcriptomic evaluation of bovine blastocysts obtained from peri-pubertal oocyte donors

Embryo production in heifers with low or high dry matter intake submitted to superovulation

Early postpartum administration of equine chorionic gonadotropin to dairy cows calved during the hot season: Effects on fertility after first artificial insemination

(more…)

Evaluation of In Vitro–Produced Bovine Embryos

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Published on: December 9, 2016

by Jennifer Barfield, PhD
Animal Reproduction and Biotechnology Lab, Colorado State University, Fort Collins, CO

At the 2014 joint meeting of the American and Canadian Embryo Transfer Associations, I presented a preconference symposium on bovine embryo grading in an interactive forum where participants provided real-time feedback on how they would grade embryos of various stages and qualities. One aspect of grading touched on was the difference between in vitro–produced (IVP) and in vivo–derived (IVD) embryos. When asked whether the attendees believed we need separate grading systems for these two types of embryos, the crowd was split with 47% of respondents supporting the development of a new system and 53% believing it is not needed. Here I will review some of the challenges involved with grading IVP and IVD embryos, the implications of these challenges, and propose a method by which researchers and practitioners could collaborate to gather data that can be easily shared and used to develop a consensus on the best guidelines for grading IVP embryos.

http://www.aeta.org/docs/Evaluation_of_in_vitro_produced_bovine_embryos.pdf

Articles of Interest

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Published on: December 9, 2016

Ovulation time in suckled beef cows is anticipated by use of low doses of progesterone and temporary calf removal on fixed timed AI protocol

Effects of eCG are more pronounced in primiparous than multiparous Bos indicus cows submitted to a timed artificial insemination protocol

Crocetin improves the quality of in vitro–produced bovine embryos: Implications for blastocyst development, cryotolerance, and apoptosis

Improving the cytoplasmic maturation of bovine oocytes matured in vitro with intracellular and/or extracellular antioxidants is not associated with increased rates of embryo development

Investigations of mammary and uterine blood flow in relation to milk yield, postpartum disease, and pregnancy result in dairy cows

Comparison of two timed artificial insemination system schemes to synchronize estrus and ovulation in Nellore cattle

(more…)

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