scholarly journals Synchronization with estradiol benzoate in the presence of the corpus luteum in Wagyu cows increases the number of medium follicles but does not interfere with in vitro production of embryos

2021 ◽  
Vol 42 (3) ◽  
pp. 1147-1158
Author(s):  
Maria Fernanda Zamai ◽  
◽  
Fábio Luiz Bim Cavalieri ◽  
Marcia Aparecida Andreazzi ◽  
Fabio Morotti ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Estradiol Benzoate ◽  
Breeding Systems ◽  
In Vitro Production ◽  
Embryo Production ◽  
Follicular Wave ◽  
In Vitro Embryo Production ◽  
Oocyte Donors ◽  
Vitro Production

Reproductive biotechnologies are emerging as an important element for livestock; however, some strategies must be modified to adapt to different breeding systems, such as the use of follicular synchronization protocols. This study aimed to evaluate follicular synchronization using estradiol benzoate (EB), in the presence of the corpus luteum (CL) from Wagyu oocyte donors in in vitro embryo production (IVEP). Rounds of IVEP were performed in heifers and cows (n=19) that were classified into three groups: G1/CL - animals with CL, G2/WCL - animals without CL, and G3/CL + EB - animals with CL that were subjected to follicular synchronization with EB at D0. The groups G1/CL and G2/WCL were considered the control and undertook the natural process of follicular dynamics. The results showed that the synchronization of the follicular wave with the application of EB in the presence of CL, presented a smaller number of small (6.05 ± 0.55) and large follicles (0.45 ± 0.15), but increased (P < 0.05) the number of medium-sized follicles (16.20 ± 0.90). However, the results of ovum pick up showed that regardless of whether or not EB was applied, and regardless of the presence or absence of CL in the Wagyu donor, there was no difference among the groups (P > 0.05) concerning the number of viable oocytes and the viability rate. It was concluded that follicular synchronization using EB in Wagyu oocyte donors that presented a CL, increased the number of medium-sized follicles. However, there was no improvement in the efficiency of ovum pick up, in vitro embryo production, and pregnancy rate.

177 PERFORMANCE OF Gyr PREPUBERTAL HEIFERS IN IN VITRO EMBRYO PRODUCTION

2016 ◽  
Vol 28 (2) ◽  
pp. 219
Author(s):  
P. M. S. Rosa ◽  
A. J. R. Camargo ◽  
R. V. Serapião ◽  
L. S. A. Camargo ◽  
C. S. Oliveira
Keyword(s):  
Cleavage Rate ◽  
Embryo Production ◽  
Exact Test ◽  
Follicular Wave ◽  
Lactating Cows ◽  
In Vitro Embryo Production ◽  
Blastocyst Rate ◽  
Oocyte Donors ◽  
La Jolla

Bovine in vitro embryo production is highly relevant for dairy systems in Brazil, and Gyr dams are commonly used as oocyte donors. The aim of this study was to evaluate the use of prepubertal Gyr heifers as oocyte donors, an alternative to anticipate reproduction of those animals. For that, 11 Gyr [4 prepubertal (PP) donors and 7 adult cows © donors] were used in ovum pickup (OPU) sessions. The PP cows presented an average of 282.5 kg and 26.75 months, and had never displayed oestrous. Non-lactating cows presenting an average of 492 kg and 136 months were selected for C. Five replicates were performed, totaling 27 OPU sessions (C-17, PP-10) and 2–3 sessions per animal. Follicular wave was synchronised by aspiration of follicles larger than 8 mm 96 h before OPU. Cumulus-oocyte complexes (COC) were classified accordingly to their quality in viable (G1, G2, and G3) or non-viable (G4). Viable oocytes were matured and fertilized, and the presumptive zygotes were cultured in SOF medium at 38.5°C and 5% CO2 in air. Cleavage rate was assessed 48 to 72 h post-insemination (hpi) and blastocyst rate at 168 hpi. Mean number of structures was analysed by t-test, and percentage of viable, G1, G2, G3, G4, cleavage, and blastocyst rates were compared among groups by Fisher’s exact test (GraphPadInstat, La Jolla, CA, USA; P = 0.05). Results are followed by standard error values. All procedures were approved by a local ethics committee. We found that despite higher (P < 0.05) numbers for both viable oocytes (PP: 15 ± 2.6; C: 6.11 ± 0.76) and total oocytes (PP: 23.70 ± 2.83; C: 8.82 ± 1.19) in the PP group, the rate of viable oocytes was similar (P > 0.05) among PP and C groups (PP: 61.5 ± 6.51%, C: 66.79 ± 3.79%). Mean numbers of G1, G2, G3, and G4 oocytes were higher (P < 0.05) in the PP group (G1 = 7.1 ± 1.18; G2 = 4.9 ± 1.74; G3 = 3.9 ± 1.09; G4 = 7.8 ± 1.38) than in the C group (G1 = 2.70 ± 0.740; G2 = 2.47 ± 0.44; G3 = 1.11 ± 0.31; G4 = 2.52 ± 0.39). However, the proportion was similar (P > 0.05) among PP and C groups (PP: G1 = 29.5 ± 4.21%; G2 = 19.5 ± 2.85%; G3 = 15.9 ± 13.5%; G4 = 35.1 ± 6.33%; and C: G1 = 27.24 ± 4.44%; G2 = 29.60 ± 5.08%; G3 = 12.34 ± 3.01%, G4 = 30.79 ± 4.93%). Cleavage rate (PP: 91.3 ± 17.94%; C: 74.09 ± 4.65%), mean blastocyst number per OPU session (PP: 3.3 ± 1.29; C: 1.76 ± 0.28), and blastocyst rate (PP: 19.74 ± 7.40%; C: 27.03% ± 4.07%) were similar (P > 0.05) among groups. We conclude that prepubertal heifers presented increased numbers of viable oocytes per OPU session, but blastocyst yield was similar to adult cows. This data suggests that prepubertal Gyr heifers can be used as oocyte donors. Support from FAPERJ and Embrapa is acknowledged.

scholarly journals Effects of superstimulation with fsh on follicular population and recovery rate of oocytes in the growing phase of the first and second follicular wave

2012 ◽  
Vol 47 (No. 2 - 3) ◽  
pp. 33-37
Author(s):  
S. Čech ◽  
V. Havlíček ◽  
M. Lopatářová ◽  
M. Vyskočil ◽  
R. Doležel
Keyword(s):  
Czech Republic ◽  
Corpus Luteum ◽  
Recovery Rate ◽  
Dairy Farm ◽  
Cumulus Cells ◽  
Dominant Follicle ◽  
In Vitro Production ◽  
Follicular Wave ◽  
Vitro Production

Effectiveness of in vitro production of embryos (IVP) is limited among other factors by the recovery rate of oocytes. Gonadotropin superstimulation can improve the recovery rate of oocytes. The effect of FSH treatment on follicular population and recovery rate of oocytes at ovum pick-up (OPU) in the growing phase of the 1st as well as the 2nd follicular wave after superstimulation was the object of our experiment. Twelve unpregnant milking cows (15&ndash;20 kg milk per day) housed on a dairy farm were used in the experiment. The cows bearing corpus luteum were synchronized by PGF<sub>2 </sub>(day 0) and they were treated by FSH (Folicotropin inj. sicc. ad us vet., Spofa Prague, Czech Republic, single doses 80, 80, 80, 80, 40 and 40 UI) in 12 h intervals on days 12, 13 and 14. Transvaginal ultrasonographic puncture of oocytes in cows bearing a new corpus luteum was performed on day 7 (OPU 1, various phase of the follicular wave, removal of the dominant follicle) and it was repeated on days 10 (OPU 2, growing phase of the follicular wave &ndash; control), 16 (OPU&nbsp;3, growing phase of the first follicular wave after superstimulation) and 20 (OPU 4, growing phase of the second follicular wave after superstimulation). All follicles &gt; 2 mm were punctured. The ovarian follicles (ultrasonographically) and numbers and qualities of obtained oocytes (microscopically) were evaluated during and immediately after OPU. Follicular population was divided to small (FS, 2&ndash;5 mm), medium (FM, 5&ndash;9 mm) and large (FL, &gt; 9 mm) follicles. Oocytes were classified as 1st (intact cumulus, &gt; 3 layers of cumulus cells), 2nd (complete 1&ndash;3 layers of cumulus cells), 3rd (incomplete layers of cumulus cells, expanded cumulus mass) and 4th (absence of corona cells, degenerated oocytes) classes. Although we found the least of FS (x = 1.0) during OPU 3, significantly more FM (x = 24.7) and FL (x = 3.1) follicles were found at this procedure in comparison with others. Likewise a significantly higher number of oocytes (x = 8.1) was obtained at OPU 3 in comparison with OPU 1 and OPU 2. Significantly higher number of FM (x = 6.1) was found and non-significantly higher number of oocytes was obtained at OPU 4 in comparison with OPU 1 and 2. The results show that administration of FSH increases the number of follicles and the number of collected oocytes in the growing phase of the 1st follicular wave after superstimulation, nevertheless a higher number of follicles and a higher recovery rate of oocytes can be expected in the growing phase of the 2nd follicular wave after superstimulation as well.

scholarly journals Effect of quality of sperm chromatin structure on in -vitro production of cattle embryos

2005 ◽  
Vol 48 (1) ◽  
pp. 32-39
Author(s):  
L. Kątska-Książkiewicz ◽  
M. Bochenek ◽  
B. Ryńska
Keyword(s):  
Chromatin Structure ◽  
Blastocyst Stage ◽  
Sperm Chromatin ◽  
In Vitro Production ◽  
Embryo Production ◽  
In Vitro Embryo Production ◽  
Bull Ejaculate ◽  
Vitro Production

Abstract. Bull effect on results of in vitro embryo production has been well documented. The aim of the present study was to find the relationship between quality of bull sperm chromatin and its effect on in vitro embryo production. Bovine in vitro matured oocytes were fertilized in vitro using capacitated spermatozoa (freshly ejaculated or frozen-thawed) of 12 bulls. Semen was simultaneously processed according to the sperm chromatin structure assay (SCSA) method and was analysed by flow cytometry. At least 3 replications of IVP with the same semen sample were done. The percentage of spermatozoa with abnormal chromatin ranged from 0.4% to 23.8%. All bulls used for the experiment were divided into three groups showing minimal (0.82% ± 6.82%), low (1.70% ± 15.82%) and high (18.16% ± 53.59%) percentages of spermatozoa with abnormal chromatin structure. Both cleavage rates and embryo development to the blastocyst stage were correlated significantly with sperm chromatin abnormalities and resulted in 23.1, 17.7 and 12.2% of blastocysts respectively for sperm with minimal, low and high percentages of chromatin abnormalities. The SCSA method may be used as a practical indicator of suitability of bull ejaculate for IVP purposes.

95 Successful Ovum Pick-Up-In Vitro Embryo Production in Lidia Cattle in France

2018 ◽  
Vol 30 (1) ◽  
pp. 187
Author(s):  
G. G. Lazo ◽  
S. Lacaze ◽  
D. Di Scala
Keyword(s):  
Transvaginal Ultrasound ◽  
Genetic Material ◽  
In Vitro Production ◽  
Blastocyst Development ◽  
Cleavage Rate ◽  
Embryo Production ◽  
In Vitro Embryo Production ◽  
Vitro Production ◽  
Maximum Humidity

Lidia cattle are a breed of Bos taurus that has been selected specially to produce bulls with the temperament and aggressiveness necessary to face a bullfighter in a ring. The genetic wealth of this fighting breed is divided into small lineages, traditionally called encastes, which has resulted in the risk of a loss of genetic variability (Ministerio de Medio Ambiente y Medio Rural y Marino, 2011; http://www.toroslidia.com/wp-content/uploads/2012/01/Programa-de-mejora-de-la-Raza-Bovina-de-Lidia.pdf). The technique to produce embryos in vitro may be a useful tool in the conservation of genetic material from this breed in a selection program. The aims of the study were to demonstrate the effectiveness of in vitro production of Lidia cattle embryos, and to evaluate variation in embryo production among males of the breed. Lidia cows, 7 to 13 years of age (n = 12), were used in an ovum pick-up (OPU)-in vitro production (IVP) program in the south of France. Ovarian superstimulation was induced with decreasing doses of pFSH (Stimufol; Reprobiol, Liège, Belgium) twice daily over 3 days (total dose: 350 µg). Transvaginal ultrasound-guided collection of cumulus–oocyte complexes (COC) was done 12 to 24 h after the last FSH injection. The COC were evaluated immediately after OPU and placed into 2.0-mL tubes (Corning Inc., Corning, NY, USA) containing 500 µL of maturation medium. A gas mix (5% CO2 in air) was injected into each tube and the tube was sealed tightly and placed in a portable incubator (Minitub, Tiefenbach, Germany) at 38.0°C for 12 h. On arrival in the Auriva IVP laboratory, tubes were opened and placed into an incubator with 5% CO2 at 38.5°C at maximum humidity to complete a 24-h maturation period. Semen was collected by electro-ejaculation previously from 5 different Lidia bulls (A, B, C, D, and E) and had been frozen by the same technique. The COC were fertilized with the frozen–thawed semen in TALP medium. Presumed zygotes were cultured in SOF medium (Minitub) to Day 7 (Day 0 = fertilization day) at 38.5°C in a 5% CO2, 5% O2, and 90% N2 atmosphere with maximum humidity. A total of 19 OPU/IVP sessions were performed, 5 cows were collected once, and 7 cows collected twice, and 143 COC were processed for in vitro embryo production. Blastocyst and expanded blastocyst numbers were recorded on Day 7. Oocyte recovery and embryo production by bull were analysed by ANOVA and blastocyst yield by Chi-square. The number (mean ± SEM) of oocytes allocated to each bull per IVP session was (P > 0.05): bull A (4.5 ± 1.9), bull B (5.8 ± 2.1), bull C (9.3 ± 2.5), bull D (6.5 ± 2.1), and bull E (7.0 ± 4.4). The cleavage rate differed among bulls (P < 0.05): bull A (4%), B (80%), C (89%), D (81%), and E (76%). The number (mean ± SEM) of blastocysts was lowest (P < 0.05) for bull A and highest (P < 0.05) for bull C (0, 3.7 ± 1.8, 7.0 ± 1.0, 4.3 ± 1.3, 4.7 ± 2.3 for bulls A to E, respectively). The blastocyst development rate (number of blastocysts/number of oocytes entering the IVF process) was also different among bulls (0, 63, 75, 65, and 67%, respectively; P < 0.05). Although there was a male effect on blastocyst production, our data demonstrate that successful in vitro embryo production in Lidia cattle is possible and suggests that this tool would be useful in a genetic program for the multiplication and the conservation of this breed.

246 INFLUENCE OF BREED AND SEASON ON IN VITRO EMBRYO PRODUCTION

2016 ◽  
Vol 28 (2) ◽  
pp. 255
Author(s):  
B. Bernal ◽  
J. Revol ◽  
J. M. Oviedo ◽  
A. Tribulo ◽  
H. Tribulo ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
In Vitro Production ◽  
Embryo Production ◽  
Significant Difference ◽  
In Vitro Embryo Production ◽  
Follicle Aspiration ◽  
Vitro Production ◽  
Difference Test

A retrospective analysis of in vitro production (IVP) data was done to determine the influence of breed and season on the production of viable oocytes and embryos. Cumulus‐oocyte complexes (COC) were obtained from 1946 ultrasound-guided follicle aspiration (ovum pickup) sessions performed at random stages of the oestrous cycle without superstimulation in Bos taurus and Bos indicus donors in commercial IVP in Argentina. Frozen-thawed conventional semen was used in beef cattle and conventional (n = 139) and sexed-selected (n = 481) semen in dairy cattle. The COC were classified, matured in B-199 medium, fertilized in IVF-SOF medium (Day 0), and cultured in SOF medium supplemented with 0.4% BSA under oil at 38.8°C, 5.5% CO2, and saturated humidity for 7 days. The number of viable COC and transferable embryos in each breed and season were compared by ANOVA and means were compared by Fisher’s Least Significant Difference test. Proportions were first transformed by arcsin and then analysed by ANOVA. To simplify the interpretation of the results, breeds were grouped as follows: dairy Bos taurus (Holstein, n = 620), beef Bos taurus (Angus and Bonsmara, n = 229), Bos taurus × Bos indicus (Brangus and Braford, n = 1045), and Bos indicus (Brahman, n = 52). There was no interaction between breed and season for any of the end points analysed (P > 0.1). Mean (± standard error of the mean) numbers of viable COC and transferable embryos were higher (P < 0.01) in Bos indicus × Bos taurus (19.3 ± 0.4 and 5.3 ± 0.2, respectively) and Bos indicus (15.8 ± 1.4 and 6.8 ± 0.9, respectively) than in beef (11.6 ± 0.5 and 3.0 ± 0.2, respectively) and dairy (8.0 ± 0.2 and 1.6 ± 0.1, respectively) Bos taurus donors. Cleavage rates were higher (P < 0.01) in Bos indicus (72%) than in the other breeds (57% for Bos indicus × Bos taurus and dairy Bos taurus and 54% for beef). Transferable embryo rates were higher (P < 0.01) in Bos indicus (41%) and Bos indicus × Bos taurus (30%) than in beef Bos taurus (26%). Dairy Bos taurus had the lowest (P < 0.01) embryo rates of all breeds (21%). In dairy Bos taurus, cleavage rates, the number of embryos produced, and transferable embryo production rates were higher (P < 0.01) when conventional semen was used (62%, 2.8 ± 0.15, and 27%, respectively) compared to sexed-selected semen (55%, 1.3 ± 0.1, and 19%, respectively). With regards to season, the number of viable COC was highest (P < 0.01) in the spring (14.3 ± 0.5), lowest in the summer (11.3 ± 1.0), and intermediate in the fall (12.2 ± 1.2) and winter (13.7 ± 1.2), which did not differ. Although not affected significantly by season, the number of embryos produced was numerically lower in the summer (2.8 ± 0.4) than in the spring (4.2 ± 0.2), winter (4.5 ± 0.5), or fall (4.6 ± 0.5). In conclusion, in vitro embryo production was directly influenced by breed and season. Bos indicus influenced cattle and the spring season were preferable for commercial IVP programs that did not include superstimulation.

293 EFFECT OF FOLLICULAR WAVE SYNCHRONIZATION ON IN VITRO EMBRYO PRODUCTION IN COWS

2006 ◽  
Vol 18 (2) ◽  
pp. 254
Author(s):  
A. F. Ramos ◽  
R. Rumpf ◽  
M. R. Mollo ◽  
J. U. Câmara ◽  
I. Pivato ◽  
...  
Keyword(s):  
Latin Square ◽  
Estradiol Benzoate ◽  
Continuous Variables ◽  
Cleavage Rate ◽  
Embryo Production ◽  
Follicular Wave ◽  
The Mean ◽  
In Vitro Embryo Production

In order to achieve the ideal time of ovum pickup (OPU) for in vitro embryo production (IVP) in cows regarding number and quality of oocytes recovered, this study investigated the effect of synchronization of wave emergence with estradiol benzoate (EB) injected 7 days prior to follicular aspiration. In a Latin square design, 12 crossbred beef cows were randomly divided into three groups, with three replicates each. Cows were synchronized with a norgestomet ear implant for 7 days followed by an i.m. prostuglandin F2� (PGF2�) injection and aspiration of all ovarian follicles larger than 3 mm in diameter. After that, follicles from cows in group 2X were aspirated twice a week with 4- and 3-day intervals, and follicles from groups 1X and 1X-EB were aspirated once a week. Cows from group 1X-EB also received an im injection of 2 mg of EB immediately after OPU. Throughout the study cows were kept with an ear norgestomet implant that was replaced every 2 weeks. Ultrasound evaluations of numbers of follicles greater than 3 mm in diameter and size of the largest follicle at the time of OPU were performed. Recovered oocytes were evaluated for quality, and the viable ones (Grades I, II, and III) were in vitro-fertilized on Day 0. Cleavage rate was evaluated on Day 2 and blastocyst production on Day 7. Continuous variables were compared by ANOVA and binomial data were compared by chi-square. For the 2X group, only data from the OPU performed 3 days after the last OPU were used for analysis. Results are presented as percentages or mean � SEM. Size of the largest follicle was greater (P < 0.05) in 1X coes (12.9 � 0.2 mm) than in 1X-EB cows (11.1 � 0.3 mm), which was greater than in 2X (9.6 � 0.4 mm) cows. The 1X cows had more follicles at OPU than 2X cows (17.5 � 0.7 vs. 14.1 � 0.9), whereas the 1X-EB group (15.9 � 0.7) was intermediate and not different from the others. There was no difference in the mean number of recovered oocytes among 2X (9.6 � 0.6), 1X (12.7 � 0.8) and 1X-EB (12.3 � 1.0) cows, and the mean number of viable oocytes among groups (5.8 � 0.5, 7.3 � 0.5, and 7.0 � 0.6) for 2X, 1X, and 1X-EB cows, respectively). The rate of viable oocytes was also similar among groups [58.8% (191/325) for 2X, 58.4% (267/457) for 1X, and 57.2% (231/404) for 1X-EB cows]. Cleavage [68.6% (131/191), 65.2% (174/267), and 68.4% (158/231)] and blastocyst [38.7% (74/191), 43.8% (117/267), and 44.2% (102/231)] rates were also not different among 2X, 1X, and 1X-EB groups, respectively. Although the use of 2 mg of EB in association with a norgestomet implant 7 days prior to OPU altered the follicular wave profile, it was not enough to improve number and quality of the oocytes recovered. Moreover, this study failed to demonstrate a positive effect of OPU earlier after wave emergence, when the effect of dominance should be less pronounced, on IVP in cows. The first author was supported by the fellowship 141077/2004-2 of CNPq, Brazil.

scholarly journals Modern achievements of the development of scientific research at obtaining in vitro sheep embryos

2020 ◽  
Vol 22 (93) ◽  
pp. 60-68
Author(s):  
O. M. Sharan ◽  
V. Yu. Stefanyk ◽  
S. G. Shalovylo
Keyword(s):  
In Vitro Fertilization ◽  
Embryo Culture ◽  
Biologically Active ◽  
In Vitro Production ◽  
Embryo Production ◽  
Vitro Fertilization ◽  
Maturation In Vitro ◽  
Key Factor ◽  
Vitro Production

New literature data on research aimed at improving the in vitro production of sheep embryos presents in the article. An analysis of the achievements of scientists from different countries to increase the efficiency of the main stages of embryo production in vitro: maturation of oocytes in vitro, their in vitro fertilization and in vitro embryo culture. In the literature experience has shown that the efficiency of oocyte maturation in vitro is significantly influenced by the experience and qualifications of scientists, the age of the egg donor, the improvement of the environment by adding roscovitin to inhibit meiosis, α-linolenic acid, cerium dioxide nanoparticles (CeO2 NPs) and sericin to accelerate nuclear maturation and increase the number of oocytes of the second meiotic metaphase (MII). The main factors influencing the effectiveness of in vitro fertilization have been identified, and the parameters of the limited time of fertilization ability of sperm and the ability of oocytes to fertilize, which is called the “fertile span”, have been determined. The main effective medium that increases the effectiveness of in vitro fertilization – synthetic oviduct fluid (SOF) with the addition of heparin and serum of cattle or sheep. The main parameters of sheep embryo culture in vitro are presented with the definition of the most commonly used media and their influence on embryonic development. Potential ways to improve the production of sheep embryos in vitro with the determination of morphological evaluation of categories of oocytes, methods of synchronization of their maturation in vitro are also highlighted. At the same time, literature data on the synchronization of oocyte-cumulus complexes with the use of a large number of inhibitors of meiotic division are presented, which according to many scientists may be a key factor in improving the efficiency of sheep embryo production in vitro. In addition, the results of studies of many scientists on the expansion of the fertile gap of oocytes of sheep cultured in vitro using certain biologically active substances were analyzed. In conclusion, the prospect of using the technology of in vitro production of sheep embryos in biomedical research is highlighted.

287 EFFECT OF FOLLICULAR WAVE SYNCHRONIZATION AND ABSENCE OF CORPUS LUTEUM ON COC RECOVERY IN Gyr (BOS TAURUS INDICUS) COWS

2010 ◽  
Vol 22 (1) ◽  
pp. 300
Author(s):  
T. Miyauchi ◽  
C. A. C. Fernandes ◽  
E. R. Oliveira ◽  
B. F. L. Alves ◽  
J. H. M. Viana
Keyword(s):  
Bos Taurus ◽  
Animal Health ◽  
Cumulus Cell ◽  
Estradiol Benzoate ◽  
Corpora Lutea ◽  
Portable Ultrasound ◽  
Follicular Wave ◽  
Main Technique ◽  
Oocyte Donors

Transvaginal guided follicle aspiration (TGFA) is the main technique used in Brazil to recover oocytes for in vitro embryo production (IVP) in bovine. Different protocols have been proposed to synchronize follicular emergence in oocyte donors, but most of them were developed for use in European breeds of cattle, which show many differences in ovarian physiology when compared with Zebu breeds. The aim of this study was to compare different protocols for preparation of Gyr (dairy zebu breed) oocyte donors. The TGFA were performed in a donor management facility located in Minas Gerais State, southeast Brazil. Pluriparous cycling Gir cows (n = 42) were used as donors. All cows underwent 3 treatments: G1 (control), no treatment before TGFA; G2, 2 mg of estradiol benzoate (EB) for follicular wave synchronization given i.m. 5 days before TGFA; and G3, norgestomet auricular implants given 9 days and 2 mg of EB plus 0.53 mg of cloprostenol given 5 days before TGFA. The interval between TGFA in the same donor was greater than 30 days. All procedures were made by the same technician, using a portable ultrasound device, disposable 19G or 20G needles, and a vacuum pressure of 80 mm Hg. The aspirated follicular fluid was collected in 50-mL Falcon tubes and sent to the laboratory for COC identification and classification under 50 × magnification. Recovered oocytes were classified according to cumulus cell layers and cytoplasm morphology. The total number of oocytes and viable COC recovered and the procedure length (min), including time spent for TGFA and laboratory manipulation, were compared. Data were evaluated by ANOVA, and means compared by Tukey’s test. A total of 126 TGFA sessions were performed, with recovery of 2,809 oocytes (20.31 ± 12.32 of COC and 14.83 ± 7.97 of viable COC per cow/session; mean ± SD). The total number of recovered oocytes and viable COC recovered were lower in G1 compared with G2 and G3 (15.18 ± 11.07 v. 21.18 ± 9.71 and 24.68 ± 9.03; and 9.53 ± 7.22 v. 16.97 ± 6.47 and 18.84 ± 8.90, respectively; P < 0.05) There was no difference (P > 0.05) between G2 and G3 on the number of oocytes or viable COCs recovered. The procedure length, however, was longer in G1 and G2 compared with G3 (49.6 ± 15.1 and 46.9 ± 13.4 v. 35.8 ± 13.1 min, respectively; P < 0.05) The shorter procedure length in G3 was probably associated with the reduced number of cows showing no corpora lutea (38/42, 90%), which resulted in reduction of bleeding and clot formation in the aspirated fluid. These results show that (1) previous follicular wave synchronization by EB can improve the number and quality of recovered oocytes; (2) the absence of corpora lutea does not increase the number of recovered COC and viable COC, but reduces the time spent in the procedure. Intervet Schering Plough Animal Health.

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