239 INFLUENCE OF BREED PREDOMINANCE ON MATURATION COMPETENCE, FERTILIZATION, AND DEVELOPMENT IN VITRO OF BOVINE OOCYTES

2013 ◽  
Vol 25 (1) ◽  
pp. 267
Author(s):  
J. Pelaez ◽  
H. Hernandez-Fonseca ◽  
A. Pirela ◽  
F. Baez ◽  
P. Villamediana ◽  
...  

The purpose of this research was to compare the competence of bovine oocytes of different breed predominance (Bos taurus v. Bos indicus) to mature and to be fertilized. This was done through the collection, selection, maturation, and fertilization of oocytes from slaughtered cows, predominantly either B. taurus or B. indicus. Only cows that were at least 5/8 B. taurus or 5/8 B. indicus, according to a series of phenotypic characteristics, such as the presence of a hump, dewlap, length of the ears, and others, were selected. To obtain cumulus–oocyte complexes, ovarian follicles (3 to 10 mm in diameter) were aspirated, and only oocytes with 2 or more layers of cumulus cells, an intact zona pellucida, and a homogeneous granular cytoplasm were selected. After selection, oocyte maturation [in vitro maturation (IVM)] and IVF were done. Frozen–thawed semen was used from one Brahman bull (B. indicus). For the evaluation of IVM as for IVF, oocytes were fixed for approximately 24 h at 4°C in a solution of ethanol : acetic acid (3 : 1). They were then stained with 1% acetic orcein. A chi-squared test was performed for all reported rates. The rate of maturation of oocytes from cows with a predominant B. indicus phenotype was 66.93%, whereas cows with a B. taurus phenotype reached 43.10% (P < 0.001). Regarding the fertilization rate, predominantly B. indicus females had 43.68% of oocytes normally fertilized and 41.74% of oocytes were abnormally penetrated. This category included polyspermic and asynchronic (abnormally developed pronucleus) oocytes. In cows with B. taurus predominance, 31.96% of oocytes were normally penetrated and 46.39% were abnormally penetrated by spermatozoa (no significant differences were found). The rate of non-fertilized oocytes was significantly different (P < 0.05) among B. indicus and B. taurus oocytes (6.79 and 17.52%, respectively). A small and nonsignificant proportion of degenerated oocytes resulted in both groups (7.79% for B. indicus and 4.14% for B. taurus). The cleavage rate was not different among phenotypic groups (36.12 and 32.30%, respectively, for B. indicus and B. taurus). In conclusion, the present results indicate that oocytes from predominantly B. indicus cows were more competent than oocytes from cows with a predominance of the B. taurus breed. Nonetheless, this superiority was not evident in terms of cleavage rates. Semen from other B. indicus and B. taurus breeds must be tested to clarify any breed interactions.

Reproduction ◽  
2002 ◽  
pp. 455-465 ◽  
Author(s):  
YH Choi ◽  
CC Love ◽  
LB Love ◽  
DD Varner ◽  
S Brinsko ◽  
...  

This study was undertaken to evaluate the development of equine oocytes in vitro and in vivo after intracytoplasmic sperm injection (ICSI) with either fresh or frozen-thawed spermatozoa, without the use of additional activation treatments. Oocytes were collected from ovaries obtained from an abattoir and oocytes classified as having expanded cumulus cells were matured in M199 with 10% fetal bovine serum and 5 microU FSH ml(-1). After 24-26 h of in vitro maturation, oocytes with a first polar body were selected for manipulation. Fresh ejaculated stallion spermatozoa were used for the experiment after swim-up for 20 min in sperm-Tyrode's albumen lactate pyruvate. Frozen-thawed spermatozoa from the same stallion were treated in a similar way. Spermatozoa were immobilized and injected into the oocytes using a Piezo drill. Presumptive zygotes were cultured in G1.2 medium for 20 or 96 h after the injection was administered, or were transferred to the oviducts of recipient mares and recovered 96 h later. In addition, bovine oocytes with first polar bodies were injected with the two types of stallion spermatozoa and fixed 20 h after injection to examine pronuclear formation. Fertilization rate (pronucleus formation and cleavage) at 20 h after injection of spermatozoa was not significantly different between fresh and frozen-thawed sperm groups in either equine or bovine oocytes. Pronucleus formation after injection of spermatozoa into bovine oocytes was significantly higher than that for equine oocytes (P < 0.05). There were no significant differences in cleavage rate or average number of nuclei at 96 h between equine oocytes injected with fresh or frozen-thawed spermatozoa. However, embryos developed in vivo for 96 h had a significantly higher number of nuclei in both sperm treatments compared with those cultured in vitro. These results indicate that good activation rates may be obtained after injection of either fresh or frozen-thawed equine spermatozoa without additional activation treatment. Injection of frozen-thawed equine spermatozoa results in similar embryo development to that obtained with fresh equine spermatozoa. In vitro culture of equine zygotes in G1.2 medium results in a similar cleavage rate but reduced number of cells compared with in vivo culture within the oviduct. Bovine oocytes may be useful as models for assessing sperm function in horses.


2010 ◽  
Vol 22 (1) ◽  
pp. 248 ◽  
Author(s):  
J. H. F. Pontes ◽  
K. C. F. Silva ◽  
A. C. Basso ◽  
C. R. Ferreira ◽  
G. M. G. Santos ◽  
...  

In recent years, Brazil has become the leading country in the world for the number of embryos produced in vitro (Thibier M 2009 IETS Embryo Transfer Newsletter 22, 12-19). This is partly due to the large numbers of Bos indicus animals in Brazil, making up about 80% of the total cattle. The mean oocyte production per ultrasound-guided follicular aspiration from Bos indicus is higher than those for European breeds (Pontes JHF et al. 2009 Theriogenology 71, 690-697). In the present study, we analyzed 5407 ovum pick ups (OPU) and compared the average production of total (n = 90,086) and viable (n = 64,826) oocytes and the number of embryos produced in vitro from Gir (Bos taurus indicus), Holstein (Bos taurus taurus), 1/4 Holstein × 3/4 Gir, and 1/2 Holstein-Gir crossbreed cows. To obtain oocytes, OPU was repeated from 4 to 7 times (mean = 5.7 ± 2.4) in each donor cow aged from 3 to 7 years (mean = 5.0 ± 2.3) during a 12-mo period. COCs (n = 90,086) obtained were classified according to the presence of cumulus cells and the oocyte cytoplasm aspect (homogeneous or heterogeneous/fragmented). The viable oocytes (n = 64,826) were in vitro matured for 24 h at 38.8°C in an atmosphere of 5% CO2 in air. Since this was a commercial programm, frozen sexed semen (2 × 106 mL-1) from Gir (n = 8) or Holstein (n = 7) sires previously tested for high efficiency was used for IVF. Fertilization was carried out (18-20 h) and the presumed embryos were cultured for 7 days in the same conditions as were used for IVM. Data were analyzed by ANOVA. On average, 16.7 ± 6.2 oocytes were obtained per OPU/IVF procedure and 71.96% were considered viable. The mean numbers of total oocytes per OPU/IVF procedure were 17.1 ± 4.4 for Gir cows (n = 617), 11.4 ± 3.9 for Holstein cows (n = 180), 20.4 ± 5.8 for 1/4 Holstein × 3/4 Gir (n = 44), and 31.4 ± 5.6 for 1/2 Holstein-Gir crossbreed females (n = 37, P < 0.01). The mean numbers of viable oocytes per OPU/IVF procedure were 12.1 ± 3.8 for Gir cows, 8.0 ± 2.6 for Holstein cows, 16.8, ± 5.0 for 1/4 Holstein × 3/4 Gir, and 24.3 ± 4.7 for 1/2 Holstein-Gir crossbreed females (P < 0.01). The average number of embryos produced by OPU/IVF were 3.2 (n = 12,243/3378) for Gir cows, 2.2 (n = 2426/1138) for Holstein cows, 3.9 (n = 1033/267) for 1/4 Holstein × 3/4 Gir, and 5.5 (n = 1222/224) for 1/2 Holstein-Gir. The average number of embryos produced per IVF session from 1/2 taurus × indicus donor cows was greater (P < 0.01) than from Bos indicus cows. The number of recoverable and viable oocytes and the number of embryos produced in vitro from Bos indicus donors were higher than from Bos taurus females. Therefore, the highest oocyte yield and the greatest embryo production were obtained from 1/2 taurus × indicus females. This work was supported by In Vitro Brasil.


1995 ◽  
Vol 7 (5) ◽  
pp. 1073 ◽  
Author(s):  
A Boediono ◽  
S Saha ◽  
C Sumantri ◽  
T Suzuki

Mature bovine oocytes were activated with 7% ethanol followed by cytochalasin B or D treatment. Most oocytes extruded a second polar body and formed one pronucleus when treated with 7% ethanol alone [35/43 (81%)]. With ethanol followed by cytochalasin B or D, overall activation frequency was 70% (309/441), with activated oocytes containing two pronuclei. The cleavage rate was not significantly different between treatment with ethanol alone and ethanol followed by 5 micrograms mL-1 cytochalasin B, but it was significantly lower than in fertilized oocytes (P < 0.01). However, the blastocyst production rate was significantly different (P < 0.01) among the treatments. The incidence of parthenogenetic embryos with normal (diploid) complements and with chromosome anomalies (2N/4N) was 68% (17/25) and 32% (8/25) respectively, and this was not affected by cryopreservation treatment. The longitudinal diameter of aggregated-four embryos cultured in vitro was greater (P < 0.01) than aggregated-two or single embryos. One of the aggregated-four parthenogenetic embryos was further cultured in vitro and developed up to Day 27 after activation, with a diameter of 2980 microns. The aggregated-four parthenogenetic embryos were transferred to five recipients. The oestrus was prolonged in three recipients and they returned to oestrus on Day 57, 62 and 67 after the previous oestrus. These results indicate that aggregating parthenogenetic embryos can prolong their survival in vitro and in vivo.


2008 ◽  
Vol 14 (6) ◽  
pp. 549-560 ◽  
Author(s):  
Morten R. Petersen ◽  
Michael Hansen ◽  
Birthe Avery ◽  
Ingrid B. Bøgh

AbstractOocyte maturation is known to affect the chances for successful fertilization, embryonic development, establishment of pregnancy and delivery of a live, healthy, and viable offspring. Two-photon laser scanning microscopy (TPLSM) has previously been used to evaluate early embryonic development without a detectable impairment of subsequent development, but has never been applied to assess mammalian oocytes throughout in vitro maturation (IVM). Visualization of structures within live oocytes during IVM, followed by fertilization and embryo culture, may improve the understanding of oocyte maturation. To visualize structures within bovine oocytes using TPLSM, it is necessary to remove the cumulus cells that normally surround the oocyte during maturation. Repeated visualization of structures within the same oocyte is possible, if movement of the oocyte can be avoided. In this article, we describe the development of a method for repeated intravital imaging of denuded bovine oocytes using an upright TPLSM equipped with a specially constructed incubator. Oocytes were stained with Hoechst 33258, and the nuclear structures were evaluated. Oocyte fertilization rate was not affected by TPLSM exposure, but the developmental capacity of the denuded oocytes was significantly reduced. This is, to our knowledge, the first article describing repeated intravital imaging during mammalian oocyte maturation using TPLSM.


2008 ◽  
Vol 20 (1) ◽  
pp. 180
Author(s):  
R. F. Gonçalves ◽  
V. H. Barnabe ◽  
G. J. Killian

Lipocalin-type prostaglandin D synthase (L-PGDS) has been identified in cow uterine tube fluid (UTF), and as fertility-associated protein in the Holstein bull seminal plasma, but its function is unclear. A previous study demonstrated that L-PGDS is associated with the bovine zona pellucida, and that antibody incubated with UTF decreased embryo development in vitro. This study was conducted to determine whether IVF of bovine oocytes would be affected by pretreating either the sperm or oocytes, or both, with L-PGDS antibody. In vitro-matured bovine oocytes were incubated for 1 h in IVF TALP medium supplemented with penicillamine, hypotaurine, epinephrine, and heparin containing (a) no antibody, or (b) a rabbit polyclonal antibody against recombinant bovine L-PGDS (α L-PGDS; 1:2000). Frozen–thawed spermatozoa were washed by a 45:90% layered Percoll gradient centrifugation and incubated for 1 h in IVF TALP with (a) no antibody, or (b) α L-PGDS. For this study we had 4 different treatments: (1) no antibody (control), (2) α L-PGDS at fertilization time, (3) α L-PGDS-treated oocytes, or (4) α L-PGDS-treated sperm. Oocytes were inseminated with 10 � 104 washed spermatozoa in 4-well culture dishes. After 18 h (39�C, 5% CO2 in air), oocytes were vortexed to remove cumulus cells and accessory spermatozoa, and fixed in 3.7% paraformaldehyde and 10% Triton X–100 for 1 h. Oocytes were washed and transferred to a solution with PBS, 0.3% BSA, and 1% Triton for 1 h, stained with Hoechst 33342, and observed in the presence of 2 pronuclei in the cytoplasm. There were 4 replicates of 200 to 250 oocytes for fertilization assays. Data were analyzed by SAS. Addition of α L-PGDS with sperm, oocytes, or both significantly decreased fertilization (P < 0.05) compared with the control: (1) 89.2 � 2.0%; (2) 19.4 � 2.0%; (3) 27.2 � 3.1%; or (4) 14.1 � 3.4%. These studies demonstrated that a rabbit polyclonal antibody against recombinant bovine L-PGDS reacts with both oocytes and spermatozoa, resulting in inhibition of fertilization in vitro, and has a possible role in bovine fertilization. This study was supported by FAPESP #2007/00363-5 and #2006/06008-0, Brazil.


2015 ◽  
Vol 27 (1) ◽  
pp. 243
Author(s):  
M. E. Dell'Aquila ◽  
F. Ariu ◽  
N. A. Martino ◽  
F. Minervini ◽  
A. Cardinali ◽  
...  

Verbascoside (VB), a bioactive polyphenol from olive mill wastewater with known antioxidant activity, was shown to act as a pro-oxidant molecule, by impairing energy/redox status and embryo developmental competence of prepubertal ovine oocytes when added at micromolar concentrations in a continuative 24-h in vitro maturation (IVM) exposure protocol (1). The aim of the present study was to determine whether a lower (nanomolar) VB concentration and a shorter exposure time (2 v. 24 h) during IVM may improve the maturation rates of prepubertal ovine oocytes and their subsequent embryonic development in vitro. Cumulus-oocyte complexes derived from the ovaries of slaughtered 1-mo-old prepubertal sheep oocytes underwent IVM in TCM 199 with 10% oestrus sheep serum, 0.1 IU mL–1 of FSH/LH, and 100 µM cysteamine, in 5% CO2 in air at 38.5°C for 24 h. Based on our previous results (Dell'Aquila et al. 2014 Biomed. Res. Int. 2014, 878062), VB was added in the IVM medium at 1.03 nM, and 2 incubation times (24 and 2 h) were tested. In the 2-h exposure group, after 2 h of exposure to VB, oocytes were washed and cultured up to 24 h without VB. A group of oocytes were cultured in absence of VB, as controls. Matured oocytes were fertilized with frozen-thawed ram semen in SOF medium for 22 h and zygotes were cultured in vitro for 8 days. Metaphase II (MII) cleavage and blastocyst rates were analysed by Chi-squared test. Embryo quality was evaluated by staining and total cell count of the blastocyst and analysis of variance (ANOVA) was applied. Differences were considered to be significant when P < 0.05. Compared to controls, VB treatment at the concentration of 1.03 nM and 24 h of exposure had no effect on MII rates (196/268, 73% v. 226/323, 70% MII/cultured oocytes; P > 0.05). However, this treatment allowed to obtain significantly higher rates of cleaved embryos/MII oocytes (156/196, 80% v. 165/226, 73%; respectively; P < 0.05), blastocyst yield/cleaved embryos (59/156, 38% v. 45/165, 27%, respectively; P < 0.05), and total blastocyst cell numbers (108.62 ± 19.87 v. 89.61 ± 26.32, respectively; P < 0.05) compared to control oocytes. The VB treatment at the same concentration but for 2 h induced only significantly higher cleavage rate (196/210, 93% v. 165/226, 73%; P < 0.05). In conclusion, our results showed that VB treatment at 1.03 nM during 24 h of IVM exerted a positive effect on in vitro embryo development of prepubertal ovine oocytes by increasing the blastocyst yield and their quality. The hypothesis that VB at nanomolar concentrations may improve cumulus-oocyte energy/redox status is under investigation.The authors acknowledge support by the Regione Autonoma della Sardegna (LR 7, Agosto 2007, no. 7, CRP-17602). The authors thank Dr D. Bebbere and L. Falchi, Dept. Veterinary Medicine, Sassari, for statistical analysis.


2018 ◽  
Vol 30 (1) ◽  
pp. 156
Author(s):  
M. J. Kim ◽  
H. J. Oh ◽  
E. M. N. Setyawan ◽  
S. H. Lee ◽  
B. C. Lee

Inactivation of maturation promoting factor requires proteolytic destruction of cyclin B that results in the loss of cyclin-dependent kinase 1 (Cdk1) activity and exit from metaphase. The aim of this study was to investigate that treatment of Ro-3306, a Cdk1 inhibitor, during post-activation could increase the development of somatic cell nuclear transfer (SCNT) embryos in dogs. Mixed breed female dogs aged at 1 to 5 years and weighing 20 to 35 kg were used in this study (approval number: SNU-160602-14-1). Canine cumulus–oocyte complexes were collected surgically by flushing oviducts with HEPES-buffered TCM-199 medium ~72 h after ovulation, which was determined by serum progesterone concentration. After removal of cumulus cells from oocytes by repeated pipetting in hyaluronidase, matured oocytes were selected for the following experiment. In experiment I, oocytes were activated with (1) 10 μM calcium ionophore and then post-activated with 1.9 mM DMAP (control); (2) DMAP along with 10 μM Ro-3306 (10 μM group); or (3) DMAP along with 50 μM Ro-3306 (50 μM group). Parthenotes were cultured in the synthetic oviducal fluid (SOF) medium after post-activation, and in vitro development was evaluated at 48 h (2-4 cell) and 72 h (6-8 cell). In experiment II, SCNT embryos were produced after oocyte enucleation, donor cell injection, fusion, and activation. Only fused cytoplasts were activated with (1) 1.9 mM DMAP (control) or (2) DMAP along with 50 μM Ro-3306 (50 μM group) and transferred to the oviducts of recipients. The day of embryo transfer was regarded as Day 0. Pregnancy diagnosis was performed by ultrasonography after Day 28 and cloned puppies were delivered Day 58 to 60. Embryo developmental rates in experiment I and II were analysed by one-way ANOVA and t-test, respectively, and pregnancy and delivery rate were analysed by chi-squared test using Graph Prism software (GraphPad, San Diego, CA, USA). The significance level was P < 0.05. Results in experiment I showed that cleavage rate of parthenogenetic embryos in the 50 μM group (89.3 ± 6.8%) was significantly higher than that of 10 μM group or control (50.8 ± 9.9% and 55.4 ± 18.8%, respectively). However, embryonic development to 4 cells and 6-8 cells was not different between treatments. In experiment II, pregnancy rates of recipients receiving embryos in 50 μM group (3/5, 60.0%) were significantly higher than that of control (2/6, 33.3%), but the number of healthy cloned puppies delivered in the 50 µM group (n = 6) versus the control (n = 2) was not different. In conclusion, post-activation with 50 μM Ro-3306 may enhance nuclear reprogramming of dog cloned embryos. This study was supported by RDA (#PJ010928032017), Korea IPET (#316002-05-2-SB010), Research Institute for Veterinary Science, Natural Balance Korea and the BK21 plus program.


Reproduction ◽  
2019 ◽  
Vol 158 (5) ◽  
pp. 453-463
Author(s):  
Joao Alveiro Alvarado Rincón ◽  
Patricia Carvalho Gindri ◽  
Bruna Mion ◽  
Ferronato Giuliana de Ávila ◽  
Antônio Amaral Barbosa ◽  
...  

The aim of this study was to evaluate the effect of exposing bovine oocytes to lipopolysaccharides (LPS) in vivo and in vitro on early embryo development. In experiment 1, cumulus oocyte complexes (COCs, n = 700/group) were challenged with 0, 0.1, 1.0 or 5.0 μg/mL of LPS during in vitro maturation (IVM). Later, in vitro fertilization (IVF) and in vitro culture (IVC) were performed. In experiment 2, COCs (n = 200/group) matured and in vitro fertilized without LPS were subjected to IVC with the same doses of LPS from experiment 1. In experiment 3, heifers received two injections of saline solution (n = 8) or 0.5 μg/kg of LPS (n = 8) 24 h apart, and 3 days later, COCs were recovered and submitted to IVM, IVF, and IVC. In experiments 1 and 3, the expression of TLR4, TNF, AREG and EREG genes in cumulus cells was evaluated. Exposure to 1 and 5 μg/mL of LPS during IVM decreased nuclear maturation (39.4 and 39.6%, respectively) compared with control (63.6%, P < 0.05). Despite that, no effect on cleavage and blastocyst rates were observed. Exposure to LPS during IVC did not affect embryonic development. In vivo exposure to LPS decreased the in vitro cleavage rate (54.3 vs 70.2%, P = 0.032), but cleaved embryos developed normally. Number of cells per embryo and gene expression were not affected by the LPS challenge in any experiment. In conclusion, although in vitro exposure to LPS did not affect early embryo development, in vivo LPS exposure reduced cleavage rate.


2018 ◽  
Vol 30 (1) ◽  
pp. 217 ◽  
Author(s):  
T. A. Rodrigues ◽  
A. Alli ◽  
F. F. Paula-Lopes ◽  
P. Hansen

Elevated temperature can compromise the ability of the mammalian oocyte to develop to the blastocyst stage after fertilization. The microenvironment of the oocyte is determined by the cellular and non-cellular components of the follicle including cumulus cells and follicular fluid. Here we tested whether follicular fluid contains molecules that can protect the bovine oocyte from heat shock during maturation, and if so, whether some of these protective molecules are present in exosomes. The experiments utilised ovaries from Bos taurus and admixtures of B. taurus and Bos indicus. Four separate pools of follicular fluid were prepared by aspiration of follicles from 48 to 70 slaughterhouse ovaries. Exosomes were isolated from follicular fluid by a series of centrifugation, filtration, and ultracentrifugation steps before being reconstituted in PBS. Each of the 4 exosome preparations was subject to particle size and concentration analysis. The experiments were designed as 2 × 3 factorial to test the effect of temperature and supplementation. Cumulus-oocyte complexes (COC) obtained from slaughterhouse ovaries were matured at 38.5°C for 22 h (control) or 41°C for 14 h followed by 38.5°C for 8 h (heat shock). Maturation was performed in the presence of vehicle (PBS), 10% (v/v) follicular fluid, or exosomes (16 × 109 particles/mL). Data were analysed by least-squares ANOVA. Orthogonal contrasts and the mean separation test pdiff were used to compare means. Effects of treatment on cumulus cell expansion (change in diameter after maturation) were replicated 5 times using 119 to 122 COC per treatment. Effects of treatment on embryonic development after fertilization of treated COC was determined in 6 replicates using 244 to 286 embryos per replicate. Expansion was reduced by heat shock (P < 0.001), and affected by treatment (P < 0.05), with both follicular fluid and exosomes preventing the decrease in expansion caused by heat shock. Cleavage was reduced by heat shock (P < 0.001) and affected by treatment (P < 0.05) and the interaction between temperature × supplementation (P < 0.05). Although heat shock reduced the cleavage rate for vehicle-treated oocytes (77 v. 67%), there was no effect of heat shock for oocytes treated with follicular fluid FF (78 v. 74%) or exosomes (79 v. 78%; SEM = 1.4%). Heat shock also reduced the percent of cleaved embryos becoming blastocysts for the vehicle group (27 v. 17%; P < 0.05) but had no effect on percent of cleaved embryos becoming blastocysts for the follicular fluid (31% v. 26%) or exosome groups (28 v. 26%). Uptake of exosomes into isolated cumulus cells and oocytes cultured at 38.5°C for 0.5, 1, 14 and 22 h was examined using labelling of exosomes with 10 µM BODIPY® Ceramide TR (Thermo Fisher Scieintific, Waltham, MA, USA) and confocal microscopy. Exosomes were taken up by cumulus cells after culture for 1 h or later but were not taken up by oocytes. In conclusion, follicular fluid exosomes protected the oocytes from heat shock and this effect seems to be mediated by cumulus cells. Study supported by BARD US-4719-14.


2004 ◽  
Vol 16 (2) ◽  
pp. 249
Author(s):  
B.X. Nguyen ◽  
N.T. Uoc ◽  
L.V. Ty ◽  
R.L. Monson ◽  
M.L. Leibfried-Rutledge ◽  
...  

Increasing the diary population and milk production is a goal of many tropical developing countries. We report in this paper an attempt to develop a system of intercontinental shipping for transfer of fresh crossbred Bos taurus×Bos indicus IVF embryos into local Laisind (Bos indicus) recipients as a way to produce tropical dairy calves with highly improved milk productivity. The production of embryos was done at BOMED, Inc (Madison, WI, USA). Oocytes collected from ovaries of Holstein (Bos taurus) at slaughter and semen from milking Gir (Bos indicus) were used for IVP. Cleaved embryos were selected for air shipping in portable incubators at Day 4 (Group 1), Day 3 (Group 2) or Day 2 (Group 3) after IVF. The duration of shipping varied from 60 to 65h. Embryo transfer was done in Vietnam. Laisind cows (Yellow cattle×Red Sindhi) with body weight more then 280kg and normal reproductive activity were selected for treatment of estrous synchronization with double 11-day interval injection of PG2α (Intervet, Boxmeer, The Netherlands) and single injection of eCG (SABC Vietnam) two days before the second injection of PG2α. Timing of injections was calculated according to the IVF schedule. Embryos collected from portable incubators were transferred to a CO2 incubator for further culture at 39°C. Two experiments were carried out: (1) transfer of embryos without sexing;; (2) transfer of embryos after biopsy and sex determination by PCR. In experiment 2, compact morulae or morula-blastocysts were selected for sex determination. Four to five blastomeres were aspirated from each embryo using a cutting pipette and an aspiration pipette of 30-μm diameter. PCR was done as previously described (Uoc et al., 1999 J. Biology). After biopsy, embryos were kept in culture for one day to observe the development in vitro. Embryos developed to morula-blastocyst or hatching blastocyst at Day 7 or Day 8 after IVF were transferred nonsurgically to recipients with estrus detected in the period from 0 to 12h before or after the starting IVF. Pregnancy was confirmed by rectal palpation 3 months after embryo transfer. The average rate of embryos developed into morula-blastocyst was more then 50% (Table 1) and there were no significant differences among different shipping groups. For experiment 2, more then 87 % of embryos biopsied developed in vitro to expanding and hatching embryos. The average rate of female embryos was 56.3%. The pregnancy rate at 3 months was more then 44% (n=188). The first group of calves was born without unusual birthing problems. In conclusion, the system of embryo transfer using intercontinental shipping of fresh IVF embryos and local Bos indicus recipients can be applied for production of dairy calves. Supported by grant from the AIRE-Development agency. Table 1 Development in vitro of IVP embryos


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