Non-surgical Transfer Research Articles

A simplified grading system for in vivo and in vitro derived vitrified equine embryos

The ability to predict the viability of embryos before vitrification and thawing has important commercial applications in any breeding program. The aim of this study was to develop and evaluate a simplified embryo grading system for both in vivo- and in vitro-derived vitrified day 8 embryos. The in vivo derived (n=109) and in vitro – intracytoplasmic sperm injection derived (n=145) embryos were produced in a commercial embryo program. The embryos were classified as Grade 1, 2 or 3 based on the amount of extruded material between the trophoblast and the zona pellucida observed during the vitrification process. The embryos were vitrified at day 8 of development in a two-step system with increasing concentrations of dimethylsulfoxide and ethylene glycol and 0.5 M sucrose in the final solution. Each embryo was thawed in 0.3 M and then 0.15 M sucrose before transfer into holding medium for non-surgical transfer into a recipient mare. Analysis of the relationship between the embryo grading system and pregnancy rates after vitrification, thawing and transfer of in vivo and in vitro derived embryos confirmed that there was a significant effect of origin (in vivo vs in vitro; P ≤ 0.05), and embryo grade (P ≤ 0.001) on embryo survival after transfer. In conclusion, this simplified grading system is predictive of embryo survival for both in vivo- and in vitro- derived vitrified equine embryos.

Is the corpus uteri a suitable site for embryo transfer in the pig?

Numerous attempts to establish a practicable means of non-surgical embryo transfer in pigs were unsuccessful until instruments were developed to permit deposition of embryos deep inside a uterine horn. Recently, however, successful non-surgical transfer of embryos to the uterine body in non-sedated recipients has been reported. These reports have prompted us to present data from a study that addresses the question of whether the commonly experienced low pregnancy rates following transfers to the corpus uteri results from the inability of endometrial receptors to recognize the presence of embryos or to the prevailing unfavorable local conditions. Blastocysts were transferred to the corpus uteri of recipients in which maintenance of pregnancy was assured by the transfer of additional embryos to the tip of a uterine horn. Embryos from pigmented and unpigmented donors were used to be able to differentiate between fetuses from embryos transferred to different sites. Fewer fetuses developed from embryos transferred to the corpus uteri than from embryos transferred to the uterine horn. This leads to the conclusion that prolonged retention of blastcysts in the uterine body under conditions inappropriate for their stage of development is responsible for an unsatisfactory pregnancy rate.

Somatic Reprograming by Nuclear Transfer.

Somatic cell nuclear transfer (SCNT) is a powerful technique, although challenging, to study reprograming into the totipotent state of differentiated nuclei in mammals. This procedure was initially applied in farm animals, then rodents, and more recently in primates. Nuclear transfer of embryonic stem cells is known to be more efficient, but many types of somatic cells have now been successfully reprogramed with this procedure. Moreover, SCNT reprograming is more effective on a per cell basis than induced Pluripotent Stem Cells (iPSC) and provides interesting clues regarding the underlying processes. In this chapter, we describe the protocol of nuclear transfer in mouse that combines cell cycle synchronization of the donor cells, enucleation of metaphase II oocyte and Piezo-driven injection of a donor cell nucleus followed by activation of the reconstructed embryos and nonsurgical transfer into pseudo-pregnant mice. Moreover, this protocol includes two facultative steps to erase the epigenetic "memory" of the donor cells and improve chromatin remodeling by histones modifications targeting.

Current Reproductive Technologies Impacting Equine Embryo Production

Numerous reproductive technologies have been developed in the past several decades, which have dramatically changed the way mares are bred. This review will focus on embryo recovery and transfer, cooled-shipped embryos, embryo freezing, oocyte freezing, oocyte collection and transfer, intracytoplasmic sperm injection (ICSI), and sexed semen. Embryo transfer procedures have been constant for many years and the costs have not changed. The major change has been the ability to store embryos at 5 C for 12–24 hours and transport them to recipient stations. Embryo freezing has become more common using the technique of vitrification of embryos >300 μm or deflating embryos >300 μm before freezing. Oocyte vitrification has resulted in poor pregnancy rates although the technique works well in women. The ability to collect oocytes from mares and fertilize them by sperm injection has revolutionized the veterinarian’s approach to infertility in the mare and/or stallion. A transvaginal approach can be used to collect oocytes from preovulatory follicles and unstimulated follicles 5–25 mm in size. Although traditional in vitro fertilization does not work well in the horse, ICSI can be used to produce blastocysts which, upon nonsurgical transfer into recipients, provide a pregnancy rate similar to fresh embryos collected from donor mares. Sorting sperm by flow cytometry into X- and Y-bearing spermatozoa has been shown to provide about a 50% pregnancy rate with freshly sorted sperm but only 12% with sorted, frozen/thawed stallion sperm. It is likely that more advanced reproductive techniques will be developed in the future. Their acceptance will depend on how well they work, perceived need, cost, and, to some extent, the breed associations.

Historical Aspects of Equine Embryo Transfer

Early embryo transfer in equids was undertaken simultaneously in the early 1970s in Cambridge, England, and Kyoto, Japan. Both groups achieved limited success when flushing the uterine horn ipsilateral to the side of ovulation but the rates improved markedly when the whole uterus was flushed on realization of the continued movement of the embryo throughout the uterine lumen after day 6. Initial transfers of embryos to recipient mares were carried out surgically, but nonsurgical transfer via the cervix has been used subsequently with increasing success, culminating in pregnancy rates of 75%–90% today. Experimental use of embryo transfer in horses and donkeys demonstrated the unique ability of equids to carry to term a full range of interspecies hybrid conceptuses and extraspecies pregnancies created by embryo transfer. Furthermore, splitting of day 4–8 cell embryos and day 6 compact morulae allowed the creation of genetically identical twin foals. But despite these and other significant advances over the past 45 years, a persisting limitation is the relatively low embryo recovery rates from donor mares treated with exogenous gonadotropins in attempts to induce them to superovulate. This is due to the toughness of the ovarian tunica albuginea which forces ovulation through the ventrally situated ovulation fossa where multiple follicles compete with each other and luteinize before they can ovulate properly.

Blastocyst hatching site is regularly distributed and does not influence foetal development in mice

Hatching out from the zona pellucida (ZP) is a crucial step for blastocyst implantation and development. However, it is still unknown whether the location of the hatching site relative to the inner cell mass (ICM) affects embryo implantation and foetal development. Here, we classified hatching blastocysts into three categories, 0° ≤ θ ≤ 30°, 30° < θ ≤ 60°, and 60° < θ ≤ 90°, in which θ is determined based on the relative position of the hatching site to the arc midpoint of the ICM. Non-surgical embryo transfer (NSET) devices were employed to evaluate blastocyst implantation and embryo development. Of 1,827 hatching blastocysts, 43.84%, 30.60%, and 21.67% were categorized as 30° < θ ≤ 60°, 0° ≤ θ ≤ 30°, and 60° < θ ≤ 90°, respectively. Embryos with different hatching sites showed no distinct differences in blastocyst implantation; surrogate female pregnancy; embryo development to term; litter size, or offspring survival, gender, or body weight. Our results indicate that mouse blastocyst hatching site is not randomly distributed. Embryo implantation and development are not correlated with the blastocyst hatching site in mice. Thus, assessment of the blastocyst hatching site should not be recommended to evaluate mouse blastocyst implantation and developmental potential.

Cryopreservation and transfer of pig embryos

Recent advances in cryopreservation and non-surgical transfer of pig embryos have made embryo transfer in pigs a commercially viable technology especially for the international transfer of valuable genetic material. Early research demonstrated that early stage pig embryos were highly sensitive to temperatures below 15°C and this sensitivity decreased with development to peri-hatching blastocysts which is accompanied by a reduction in lipid content. Removal of the lipid prior to freezing was found to improve the freezability and resulted in the birth of piglets. It was shown that by polarising the lipid material out of the blastomeres and using ultra rapid freezing (vitrification) the early stage zona pellucida intact embryo would also survive freezing and result in the birth of piglets. Other factors that have contributed to successful cryopreservation of the early stage pig embryo include the use of cytoskeletal stabilising agents, specific cryoprotectants, increasing cooling rates using open pulled straws or micro droplets and assisted hatching. The present review discusses the relative importance of each of these factors. The development of non-surgical transfer technology and its importance in the application of embryo transfer in the pig industry is also reviewed.

Nonsurgical Embryo Transfer Protocol for Use with the NSET™ Device.

Genetically modified embryos must be transferred to a suitable female recipient for development to pups. Nonsurgical embryo transfer is a fast and efficient method used to deliver blastocyststage embryos to the uterine horn of recipient females. The efficiency of recovery of pups after nonsurgical embryo transfer is similar to the efficiency after surgical transfer. However, nonsurgical transfer eliminates the pain and distress caused by the surgical procedure and provides a refinement in accordance with Russel and Burch's "3Rs" (The principles of humane experimental technique. Methuen & Co., London, 1959), an ethical framework for animal research. This method is also useful for rederivation of mouse strains. Rederivation is important for either removal of potential pathogens from an incoming mouse strain after shipping, or within a facility to obtain a clean mouse colony.

The influence of Multiple Ovulation and Nonsurgical Embryo Transfer on pregnancy rate in Holstein Friesian Heifers

This study was carried out by selecting a total number of 17 Holstein Friesian cows divided into two main groups, the first group (4) cows as donors used to take the embryos from after artificial insemination and the second group (13) heifers cows as recipients for embryos. The same techniques were used on donor and recipient cows for the purpose of hormonal preparation in terms of instance synchronization, preparing recipient cows and superovulation for donor cows. Artificial insemination were done in field, and a nonsurgical flushing procedure embryos applied then graded. Donors reflected a good response to superovulation hormonal treatment. The total number of transferable embryos was 13 from four donors. Evaluation of all embryos was excellent quality. The pregnancy rate results for recipient cows was 61.5%. This result is an acceptable as compared to previous studies due to many factors, the study aim was taking into account all these factors, that can have an influence on these programs to obtain genetically improved animals in a shorter time and lower costs.

87 Effect of Treatment with Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) on Pregnancy Rates of Recipient Alpacas Post-Embryo Transfer

The aim of the study was to improve the pregnancy rate in recipient alpacas using nonsteroidal anti-inflammatpry druds (NSAIDs) at time of embryo transfer. Because most NSAIDs are non-selective inhibitors of cyclooxygenases, which are the rate-limiting enzymes in the formation of prostaglandins, such treatment could temporarily block the production of prositaglandin F2α (PGF2α) and hence maintain corpus luetum (CL) activity long enough to support embryo development and pregnancy. The experiment was carried out in the Peruvian southern highlands (4,100 m elevation). Thirty-one adult alpaca donors were subjected to superovulation and embryo flushing as described previously (Vivanco-Mackie 2013 Proc. 29th Annu. Mtg. AETE, Istanbul, pp. 43-74; http://www.aete.eu/index.php/publications-aete/proceedings/2013/file). From the collected embryos, 20 grade A embryos were selected and transferred fresh into the recipients of the 2 experimental groups. All embryos were collected and transferred at 6.5 days post-mating of the donors with one embryo transferred per recipient. Recipient alpacas (n = 20) were synchronized and induced to ovulate after a selection made by ultrasonography, selecting as recipients the alpacas with follicles &gt;8 mm and then exposing them to vasectomized males followed by IM injection of gonadotropin-releasing hormone (GnRH, 0.0084 mg of acetate of buserelin). Embryo transfers were made by laparoscopically aided laparotomy 6.5 days after ovulation induction as this method has been demonstrated to be more effective in previous trials compared with transcervical non-surgical transfers. At the time of embryo transfer, the recipients were randomly assigned to 1 of the 2 treatments according to the NSAID injected immediately after embryo transfer: Treatment 1 (10 alpacas) was an IM injection of meloxicam at 0.5 mg/kg of body weight; treatment 2 (10 alpacas) was an IM injection of tolfenamic acid at 3 mg/kg of body weight. At the pregnancy test by ultrasound scanning on Day 58 post-transfer, 30% (3/10) of the recipients had a live fetus in treatment 1, whereas treatment 2 had only 10% (1/10).The difference was not significant (P &gt; 0.05) based on Chi-squared analysis. Th historical pregnancy rate obtained with fresh embryos transferred using the same technique and on the same farm where the comparison between NSAIDs was performed was 28.6% at 58 days post-transfer (Vivanco-Mackie et al. 2015 Reprod. Fertil. Dev. 27, 173 abst). Results suggest that there is no difference between tolfenamic acid and meloxicam in their effect on pregnancy rates in alpacas receiving fresh embryo transfers. Compared with historical data of nontreated recipients, results of the present experiment may indicate that the use of NSAIDs at the time of embryo transfer does not improve pregnancy rates in alpaca fresh embryo recipients. However, additional research studies with greater numbers of recipients and an untreated control group are necessary to confirm the preliminary results of the present study. The study was funded by the ‘INNOVATE PERU’ program of the Peruvian Government.

In vivo Embryo Production and Non-Surgical Embryo Transfer in Different Breed of Superior Sow

<i>In vivo</i> Embryo Production and Non-Surgical Embryo Transfer in Different Breed of Superior Sow

Is spontaneously double ovulation associated with an incidence of EPL after non-surgical embryo transfer in mares?

Is spontaneously double ovulation associated with an incidence of EPL after non-surgical embryo transfer in mares?

A nonsurgical embryo transfer technique in mice

Although efficient nonsurgical transfer of embryos in mice would provide many advantages over a surgical method, the low success rate of nonsurgical transfer has hampered its acceptance and use. Here, a plastic catheter was used to mimic embryo transfer process and then the transfer efficiency was evaluated by intrauterine trypan blue dye dispersion. Also 3.5-day blastocysts from natural pregnant mice were transferred through cervix into uterine horns. The results show that 70.9% of CD-1 mouse 3.5-day blastocysts transferred into unilateral uterine horns of pseudopregnant 2.5-day recipients can be developed to live newborns, and an efficient mouse nonsurgical embryo transfer technique was established. The technique was simple, rapid, inexpensive, unlikely to get contaminated, ethical and do not need specialized apparatus, and can completely replace surgical embryo transfer techniques. Moreover, the mouse nonsurgical embryo transfer technique provides a research model for human and other large animal embryo transfer.

164 EMBRYO SURVIVAL TO CALVING ACCORDING TO TYPE OF EMBRYO AND EMBRYO TRANSFER METHOD IN ALPACAS

The objective of the study was to determine the embryo survival up to calving of fresh and cryopreserved (frozen and vitrified) alpaca embryos transferred into alpaca recipients by nonsurgical transcervical embryo transfer and by surgical laparoscopically aided embryo transfer. For this report we have compiled the information from 127 embryo transfers in alpacas done by our group at Mallkini, Puno, Peru, at 4200 m elevation. The embryos have been collected from superovulated donor alpacas flushed at 6.5 days post mating, some were transferred as fresh and some were cryopreserved; the recipients (3 to 7 years old) were selected based on presence of functional corpora lutea at ecosonographic examination and subjected to ovarian cycle synchronization and ovulation induction as per Vivanco (2013). From a total of 133 alpacas selected, 127 were used, from which 82 received fresh, 32 frozen, and 13 vitrified embryos. All embryos were classed as A-class expanded blastocysts at time of transfer. By nonsurgical transcervical embryo transfer, 33 embryos were transferred fresh, 22 were frozen/thawed embryos, and 13 were vitrified/warmed embryos. By surgical laparoscopically aided method, 49 embryos were transferred fresh and 10 embryos were frozen/thawed; no vitrified embryos were transferred by this method. Results are detailed in Table 1. Pregnancy losses occured at up to 9 weeks (63 days) of gestation, the heaviest loss occurs in the first 3 weeks. After 9 weeks of gestation, no losses were registered. In average, 22% of fresh embryos transferred were represented as crias born. None of the cryopreserved embryos survived up to 11 weeks post-transfer. There is no difference in percentage of crias born between nonsurgical transcervical embryo transfers and surgical laparoscopically aided embryo transfers.The heavy embryo losses could be related to nutrition and high-altitude limitations; however, it is difficult to make comparisons with others because reports to date lack information on the actual crias born from embryo transfers in alpacas; most of the reports are based on pregnancy reports up to 30 to 60 days post-transfers. To date, no births from cryopreserved alpaca embryos have been reported. Furher studies on causes of embryo/fetal losses are necessary. Table 1.Results of embryo transfer This study was financed by the Peruvian Fund for Innovation, Science and Technology (FINCYT).

151 REPRODUCTIVE PARAMETERS OF MINI-HORSE MARES

The Mini-horse is a new equine breed that is on the rise in Brazil. These are animals with a maximum adult height of 98 cm for females and 93 cm for males, with a well-proportioned body. Those animals are easily handled by children and require small spaces with low maintenance costs. The Mini-horse is under constant genetic selection that is aimed mainly at decreasing its height. For this reason, mares of low stature are required, justifying their use in assisted reproduction programs. Reproductive data of these animals are not available in the literature. Only data of full-size mares are referenced, not taking into account the particularities of this breed. Therefore, the aim of this study was to describe one technique of embryo transfer (ET) for Mini-horse mares. Reproductive rates obtained during the 2012/2013 Brazilian breeding season are presented. Thirteen Mini-horse donor mares were monitored daily by transrectal ultrasonography and ovulation induction was performed with injection of deslorelin acetate or hCG, along with natural breeding using the same stallion for all mares. Eight days after detection of ovulation, flushing for embryo collection was performed. The recipient mares were also monitored daily to detect ovulation and those selected ovulated in the range of up to four days after the donor mare. In order to prevent cervical injuries, the large catheter traditionally employed in uterine washing of large mares was replaced by a Foley catheter (24 Fr in diameter). A range of 50 to 250 mL of Ringer's lactate solution was used to fill the uterus up to 5 times or until the embryo was observed in the collector filter. After the embryo collection, the donor mare received a dose of luteinizing drug (sodic cloprostenol – Sincrocio®, Ouro Fino, Brazil). The recipient mare was examined for a corpus luteum, absence of uterine fluid or endometrial oedema, and good cervical and uterine tone. Recipients were also selected by height (similar to donors) so that the newborn foal could reach the recipient mare's udder to nurse. For non-surgical transfer, the embryos were aspirated by an artificial insemination pipette with ~0.5 mL of holding medium interspersed with small columns of air and then inserted into the uterine body of the recipient mares. Daily follicular growth was 2.2 ± 1.0 mm and the size of follicles at ovulation induction was 31.6 ± 2.8 mm. In 57 embryo collections performed, 46 embryos were obtained and transferred into the uteri of recipient mares, resulting in 35 pregnancies. The embryo recovery and pregnancy rate were 80.7% and 76.1% respectively. The relationship between pregnancy and number of embryo flushes performed was 61.4%. The time between two consecutive flushes was 20 ± 4.5 days. The rate of embryonic loss between 20 and 60 days was 20%. The easy handling of the animals and the high rates of ET program success were promising. However, information regarding full-size mares should be used with caution, respecting the specific characteristics of this breed.

Successful Nonsurgical Transfer of Bovine Elongating Conceptuses and Its Application to Sexing

The objectives of the present study were to establish a nonsurgical transfer method for elongating bovine conceptuses and to combine this method with biopsy and sexing. Bovine conceptuses were recovered from donor cows on days 13–14 of the estrus cycle. In experiment 1, day 13 conceptuses were transferred to recipient cows using a standard day 7 embryo transfer (ET) method. The pregnancy rate of day 13 conceptus transfer (CT) is comparable to that of day 7 ET. In experiment 2, day 14 conceptuses were transferred using modified methods (balloon catheters or ET guns with modified sheaths). Using the standard ET method, no pregnancies were obtained; however, when balloon catheters or ET guns with modified sheaths were used, the pregnancy rates after CT were 48.0% and 44.8%, respectively. In experiment 3, day 14 conceptuses were biopsied without a micromanipulator, sexed using the loop-mediated isothermal amplification method and transferred to recipient cows. The pregnancy rate of biopsied conceptuses was 46.2% and did not differ significantly from that of unbiopsied conceptuses. Moreover, all pregnant cows transferred conceptuses following biopsy and sexing delivered calves with the expected sexes. These results suggested that the nonsurgical bovine CT method was comparable to day 7 ET and that this technique enables biopsy and sexing without expensive equipment such as a micromanipulator or specialized skills.

Complete method to obtain, culture, and transfer mouse blastocysts nonsurgically to study implantation and development

To illustrate an efficient, complete, step-by-step protocol for studying implantation in mice. Video presentation of an animal model for research in reproductive biology. Mouse (Mus musculus). A nonsurgical embryo transfer system very similar to that used for human embryo transfer. The protocols with recipient and donor mice are performed in parallel in the same week. For the donor mice: the first step is ovarian stimulation, followed by ovulation induction and mating; finally, the mice are sacrificed, and the embryos are collected and cultured. For recipient mice: first estrous synchrony is induced, followed by mating with a vasectomized male, visualization of the vaginal plug, and nonsurgical transfer of the embryos. Finally (optionally), the implantation sites can be visualized on day 7.5 of development. (All animal experiments were performed with the approval of the institutional review board.) Implantation is an essential step in human reproduction although, because of technical and ethics considerations, still relatively little is known about human implantation and early development. Conversely, mouse models are well established and can be used for preliminary experiments. However, there are various bottlenecks in the procedure for obtaining and transferring murine embryos, which makes experimentation with this model more difficult. These difficulties include pseudopregnancy, ovarian hyperstimulation, and embryo collection, culture, and transfer. We have proposed a complete, efficient method for obtaining, culturing, and transferring mouse blastocysts that can be easily applied in research. Potential applications include testing new media components that do not affect preimplantation but do affect implantation and early development. The embryo transfer method proposed here has been demonstrated to achieve embryo implantation easier and faster than, and in approximately similar rates as other traditional surgery methods. This workflow is the first set of complete step-by-step instructions available that incorporate advances such as nonsurgical mouse embryo transfer. This will facilitate research into different reproduction events such as embryo development, embryo implantation, or contraception.

179 AUTOGENOUS TRANSFERS OF INTRACYTOPLASMIC SPERM INJECTION-PRODUCED EQUINE EMBRYOS INTO OOCYTE DONORS' UTERI

Intracytoplasmic sperm injection (ICSI) is used to produce offspring from stallions with poor quality or limited availability of semen. Embryos produced by ICSI can be cultured to a stage of development suitable for nonsurgical transfer into recipient uteri. However, use of a recipient is expensive, and transfer of an ICSI-produced embryo back into the oocyte donor's uterus would allow her to carry the pregnancy. We attempted autogenous transfers of ICSI-produced embryos back into the oocyte donors’ uteri for 3 mares in a clinical setting. Three Quarter Horse mares, aged 9, 10, and 13 years, were admitted to the clinical assisted reproduction program at Colorado State University's Equine Reproduction Laboratory (Fort Collins, CO, USA). When a follicle or follicles at least 33 mm in diameter, relaxed cervix, and uterine oedema were observed, deslorelin acetate (1.25 mg, IM) and hCG (2000 IU, IV) were administered. Approximately 22 h later, oocytes were collected by transvaginal, ultrasound-guided follicular aspirations. Oocytes were placed in culture, and 18 to 20 h later, ICSI was performed using frozen sperm from 4 stallions (A–D), all with limited semen availability. Resulting embryos were cultured in DMEM/F12 with 10% fetal calf serum at 38 to 38.5°C for 5 or 6 days, when all embryos reached the blastocyst stage. Oocyte and embryo cultures were performed as previously described (Carnevale et al. 2010 Anim. Reprod. Sci. 121S, S241–243). Blastocysts were transferred nonsurgically into the uteri of recipients or donors, and pregnancies were observed by ultrasound at 12, 16, 25, and 35 days. The 9-year-old donor had 2 oocyte collection cycles. An oocyte was not retrieved during the first cycle; 2 oocytes were collected the second cycle, resulting in 2 blastocysts. One blastocyst was transferred into a synchronized recipient, who did not become pregnant; the second blastocyst was transferred into the donor, resulting in a pregnancy (stallion A). The 10-year-old mare had a single oocyte collection cycle yielding 2 oocytes, and 2 blastocysts were produced from the same stallion (B). One blastocyst was transferred into the uterus of a synchronized recipient, and one blastocyst was transferred back into the donor's uterus. Both mares were diagnosed pregnant, but the recipient lost the pregnancy between 25 and 36 days. The 13-year-old donor donated a single oocyte during her first cycle, resulting in a blastocyst that was transferred into a recipient and a pregnancy (C). Two oocytes were obtained during the subsequent cycle and injected with sperm from different stallions; 1 presumptive zygote did not cleave after ICSI (D), and the second resulted in a blastocyst that was transferred back into the donor, resulting in a pregnancy (A). In total, 7 oocytes were collected during 5 cycles, resulting in 6 blastocysts and 5 pregnancies, with ongoing pregnancies in 1 recipient and in the 3 oocyte donors. Pregnancies were established for 3 stallions (A–C). The methods used were effective in producing clinical pregnancies in oocyte donors after oocyte collection, ICSI, and nonsurgical embryo transfer.

Design, development, and application of a non-surgical deep uterine embryo transfer technique in pigs

There is enormous potential for the use of embryo transfer in pig production because it should make it possible to move genetic material (i.e., embryos) with minimal risk of disease transmission, reduced transportation costs, and no effect on animal welfare during transport. Unlike other livestock, the commercial use of embryo transfer in pigs has been very limited because embryo collection and transfer require surgical procedures. Recently, a new and unique procedure for the non-surgical transfer of porcine embryos deep into a uterine horn of non-sedated gilts and sows has been developed. The excellent reproductive performance of recipients following non-surgical transfer of fresh embryos and the promising results obtained with vitrified embryos represent a fundamental advance in the widespread commercial use of embryo transfer by the pig industry.

비외과적 수정란 이식에 의한 형질전환 소 생산 기술

비외과적 수정란 이식에 의한 형질전환 소 생산 기술