258 FACTORS AFFECTING COMMERCIAL SEXING PROGRAM AND MULTIPLE GENETIC ANALYSIS PERSPECTIVES OF IN VITRO-PRODUCED BOVINE EMBRYOS

2009 ◽  
Vol 21 (1) ◽  
pp. 227
Author(s):  
R. V. Alonso ◽  
J. A. A. Hellú ◽  
S. H. V. Perri ◽  
J. A. Visintin ◽  
J. F. Garcia

The present study aimed to evaluate the interactions among different factors on the viability and sex ratio of in vitro-produced (IVP) bovine embryos, submitted to a large scale sexing program. Additionally, whole genome amplification (WGA) technology was used to amplify genomic DNA from IVP bovine embryo biopsies, in order to perform multiple genetic analyses. The survey was performed in a 4650 IVP bovine sexed embryo database. Embryos were biopsied by a microaspiration technique and sex was determined by PCR of DNA from the biopsy. Only female embryos were transferred to synchronized recipients. Pregnancy diagnosis and fetal sex determination were carried out by ultrasound. The variables were classified in accordance with embryo sex (male, female, and indeterminate), five laboratories (A, B, C, D, and E), six bovine breeds (Nellore, Brahman, Girolando, Simmental, Holstein, and Jersey), embryo stage (MO, EB, BL, XB, and HB), embryo quality (1, 2, and 3) and biopsy quality (“standard” and “nonstandard”). The statistical analysis was carried out by association chi-square test, chi-square for a 1:1 ratio, and logistic regression analysis (PROC LOGISTIC) of SAS. PCR showed 93.3% efficiency, 93.2% accuracy, and male and female rates of 52.9% and 47.1%, respectively. Mortality rate of biopsied embryos was 10.3% and pregnancy rate was 31.7%. Significant differences were not observed between male and female viability, although indeterminate embryos resulted in more death after micromanipulation. For quality 2 and 3 embryos, the mortality rate after biopsy was 3.19 and 11.37 fold higher, respectively, than for quality 1 embryos. For embryos whose biopsies were classified as nonstandard, the embryonic mortality rate was 3.6-fold higher than standard ones. Mortality rate was not affected by embryo stage at biopsy (P > 0.05). Although sex ratio was significantly skewed to male embryos, differences were not observed among laboratories (P > 0.05) and breeds (P > 0.05) on the sex ratio of IVP bovine embryos. To test the feasibility of using WGA method for multiple genetic analysis, biopsies from 28 IVP embryos were submitted to the GenomePlex Single Cell System (Sigma-Aldrich, St. Louis, MO, USA). Aliquots from each DNA sample were purified using column chromatography and submitted to PCR using sexing primers BRY4a, SRY, UMN0920, and S4B. PCR was successful and in agreement among tested DNA aliquots from each single biopsy. The WGA strategy used herein was a useful tool for applications involving restricted amounts of starting genetic material (DNA), such as in preimplantation genetic diagnosis using IVP bovine embryos. To FAPESP and UNESP.

2013 ◽  
Vol 25 (1) ◽  
pp. 211
Author(s):  
M. De Blasi ◽  
M. Rubessa ◽  
G. Zullo ◽  
L. Boccia ◽  
V. Longobardi ◽  
...  

Most systems for producing bovine embryos in vitro use glucose as an energy source despite putative toxic effects. Glucose has a selective embryotoxicity towards female embryos, due to the higher expression of the X-linked glucose-6-phosphate dehydrogenase gene (Kimura et al. 2005 Mol. Reprod. Dev. 72, 201–207). Recently, the replacement of glucose with citrate and myo-inositol in SOF medium supplemented with 5% bovine serum (BS) increased the percentage of female embryos (Rubessa et al. 2011 Theriogenology 76, 1347–1355). Serum also affects the sex ratio of in vitro-produced (IVP) bovine embryos, favoring the male gender (Gutierrez-Adan et al. 2001 Theriogenology 55, 1117–1126). The aim of this work was to evaluate the effect of glucose replacement with myo-inositol during in vitro culture, in the presence of either BS or BSA, on bovine embryo sex ratio. Abattoir-derived oocytes (n = 1164, over 4 replicates) were matured and fertilized in vitro as previously described (Rubessa et al. 2011). After 20 to 22 h of gametes co-incubation, zygotes were denuded and cultured for 7 days in SOF with: group A) 0.34 mM trisodium citrate + 2.77 mM myo-inositol + 5% BS (n = 287); group B) 0.34 mM tri-sodium citrate + 2.77 mM myo-inositol + 8 mg mL–1 BSA(n = 290); group C) 1.5 mM glucose + 5% BS (n = 302) and group D) 1.5 mM glucose + 8 mg mL–1 BSA (n = 285). Representative samples of blastocysts produced in each group (n = 96, 58, 99, and 70, respectively in groups A, B, C, and D) were sexed by PCR as previously described (Rubessa et al. 2011). Differences among groups in blastocyst yields were analyzed by ANOVA. The percentages of female embryos were analyzed by chi-square test. Blastocyst rates in group C were lower (28.1%) than those recorded in groups A, B, and D (35.9, 41.0 and 36.1%, respectively; P < 0.01). A higher (P < 0.05) percentage of female embryos was observed in group A (61.5%) compared to group C (45.5%), with intermediate values in groups B (51.7%) and D (60.0%). Therefore, the replacement of glucose with citrate and myo-inositol favored the development of female embryos in the presence of BS but was ineffective in the presence of BSA. Furthermore, when glucose was the energy source, a tendency to greater incidence of female embryos was observed when the medium was supplemented with BSA rather than BS (P = 0.06). As a small amount of glucose is present in the BS, we hypothesize an additional glucose-dependent toxic effect on female embryos in group C. However, we cannot rule out that other factors present in the BS may interact with the energy source, playing a role in determining the sex ratio. Furthermore, the shift in sex ratio in favor of males or females embryo can be due to a better development of embryo of one sex, or to the delayed development or degeneration of embryos of the other sex. In conclusion, these results suggest that manipulating the metabolic profile of the embryos during culture may have an impact on both blastocyst production and sex ratio.


2011 ◽  
Vol 23 (1) ◽  
pp. 157
Author(s):  
M. Garcia-Herreros ◽  
I. M. Aparicio ◽  
D. Rath ◽  
T. Fair ◽  
P. Lonergan

Glucose metabolism plays an important role in energy balance control in mammalian cells and has been widely used as an indicator of embryo developmental competence. Previous studies have shown that developmental kinetic rates following IVF are lower in female than in male blastocysts, which may be related to differences in glucose consumption and metabolism. In addition, we have demonstrated that inhibition of phosphatidylinositol 3-kinase (PI3-K) with a structurally unrelated inhibitor, LY294002, suggests a negative role for PI3-K in the regulation of bovine embryo development (Aparicio et al. 2010 Reproduction 140, 83–92). The aim of this study was to determine whether PI3-K has a role in the regulation of glucose metabolism in Day 7 bovine blastocysts and to study the possible differential protein expression involved in glucose metabolism [hexokinase-I (HK-I), phosphofructokinase-1 (PFK-1), pyruvate kinase1/2 (PMK1/2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase A/C (LDHA/C), glucose transporter-1 (GLUT-1) and glycogen synthase kinase-3 (GSK-3A/B)] between in vitro produced male and female embryos derived from IVF with either X- or Y-sorted semen. Day 7 blastocysts derived from unsorted semen (n = 25 blastocysts per group) were incubated up to 12 h in SOF culture medium in the presence or absence of LY294002 (10 μM) and stored. Similarly, male and female Day 7 blastocysts derived from sorted semen were collected apart and stored at –80°C until proteomic analysis (Western blot analysis of proteins separated by sodium dodecyl sulfate-polyacylamide gel electrophoresis). Inhibition of PI3K significantly decreased HK-I (P < 0.01), PFK-1 (P < 0.001), GAPDH (P < 0.05), GSK-3A/B (P < 0.001), and GLUT-1 (P < 0.01) protein levels. Interestingly, protein expression of HK-1 (P < 0.001), PFK-1 (P < 0.01), PMK1/2 (P < 0.05), GAPDH (P < 0.01), and GLUT-1 (P < 0.001) was significantly higher in male compared with female blastocysts. The significant increase in the phosphorylated forms (Ser21 and Ser9) of both isoforms (GSK-3A/B) in male compared with female embryos is indicative of a higher inactivation of GSK-3A/B in males (P < 0.001). The presence of LDHA/C activity was not detected in any blastocyst group, irrespective of the gender or treatment studied. In conclusion, our data suggest that PI3K plays a major role in the regulation of glucose metabolism in bovine embryos, because pretreatment with LY294002 significantly modified the protein expression of HK-I, PFK-1, GAPDH, GSK- 3A/B, and GLUT-1, and underline the possibility of modulating glucose metabolism via the PI3K cellular pathway. The differential glycolytic metabolism between male and female blastocysts might explain the higher developmental kinetic rates in males described by other authors, because the expression of proteins involved in glycolysis and glycogenogenesis was significantly higher in male than in female in vitro-produced bovine embryos.


2019 ◽  
Vol 31 (1) ◽  
pp. 137
Author(s):  
T. Fujikawa ◽  
Y. Gen ◽  
S.-H. Hyon ◽  
C. Kubota

Carboxylated poly-l-lysine (CPLL) is an ampholytic polymer compound and a polyamino acid with a known functional resemblance to antifreeze proteins. We previously reported that CPLL is an effective cryoprotectant for bovine cells, sperm, and slow-frozen embryos. In this study, we investigated CPLL as a cryoprotectant for vitrified bovine embryos. We developed bovine embryos in vitro and vitrified them at the blastocyst stage. Embryos were equilibrated (3min) and vitrified (1min). Vitrified embryos were cryopreserved in LN (Cryotop® device; Kitazato Corp., Tokyo, Japan) for at least 1 week, thawed with a 0.3M sucrose warming solution, and then cultured in a basal medium (Gibco® medium 199, Grand Island, NY, USA; supplemented with 100µM 2-mercaptoethanol, 10% fetal bovine serum, and antibiotics) at 38.5°C in a humidified atmosphere (5% CO2, 5% O2, 90% N2). We evaluated the embryos morphologically for survival and hatched rate at 0, 24, 48, and 72h post-thawing. In control, the equilibration solution (ES) consisted of 7.5% (vol/vol) dimethyl sulfoxide (DMSO) and 7.5% (vol/vol) ethylene glycol, and the vitrification solution (VS) consisted of 16.5% (vol/vol) DMSO and 16.5% (vol/vol) ethylene glycol and 0.5M sucrose. In this study, CPLL was added to ES and VS at various concentrations instead of DMSO. The CPLL was added at 16.5, 11.0, 5.5, and 2.2% (wt/vol) to VS; respectively, these solutions were named P16.5, P11.0, P5.5, and P2.2. The ES was used 45% CPLL of VS each. Embryos underwent the above procedure concurrently, with testing replicated at least 3 times. We evaluated 88, 34, 38, 44, and 28 embryos with each solution (control, P16.5, P11.0, P5.5, and P2.2, respectively). Results were analysed statistically with a chi-square test and residual analysis, regarding P&lt;0.05 as significant. Survival rates were significantly greater in P11.0 at 24h post-thawing (55.7% v. 89.5%; P&lt;0.05) and in P11.0 and P5.5 at 48h post-thawing (47.7% v. 78.9% and 47.7% v. 79.5%, respectively; P&lt;0.05) relative to controls but showed no significant differences at 0h post-thawing. Hatched rates were significantly greater in P11.0 and P5.5 through 72h post-thawing relative to controls (44.7% v. 22.7% and 52.3% v. 22.7%, respectively; P&lt;0.05). The CPLL improved post-thawing embryo survival and hatched rates when applied during vitrification, thus demonstrating cryoprotective effectiveness. We conclude that CPLL acts as a low-toxicity cryoprotectant for vitrified bovine embryos, and our results are consistent with previous reports of protective CPLL effects for cells and cell membranes.


2007 ◽  
Vol 19 (1) ◽  
pp. 259 ◽  
Author(s):  
M. Alomar ◽  
H. Tasiaux ◽  
S. Remacle ◽  
F. George ◽  
D. Paul ◽  
...  

The between-bulls variation in in vitro fertility and the shift of sex ratio toward male embryos are two problems affecting the in vitro production (IVP) of bovine embryos. Our objective was to evaluate the possible correlation between the kinetics of fertilization, embryo development, and the sex ratio of the resulting embryos. In a first experiment, and using frozen-thawed semen of 4 different AI bulls, the kinetics of pronucleus (PN) formation was evaluated at 8, 12, and 18 h post-in vitro insemination (hpi) after fixation and staining with Hoechst 33342. Fertilized oocytes were classified in 3 PN stages: PN1: showing the first signs of sperm head decondensation; PN2: with two pronuclei of different sizes, the two being far from each other; and PN3: showing two symmetric pronuclei of equal size, close to each other. Differences between bulls were observed at each time point, but were greater at 12 hpi than at 8 or 18 hpi. At 8 hpi and 12 hpi, bull C showed a significantly faster PN formation by comparison with the 3 other bulls (chi-square test: P &lt; 0.05), whereas at 18 hpi, the proportion at each of the PN stages was similar to that of bulls A and D, with bull B showing delayed PN development. In a second experiment, a standard IVP procedure was conducted with the 4 bulls to determine cleavage and blastocyst rates. The timing of first cleavage was measured using time-lapse cinematography. Compared with those of bull B, the embryos generated with bull C led to significantly higher Day 7 blastocyst yields (31.3 � 9.5% vs. 21.9 � 6.7%; ANOVA: P &lt; 0.05). Moreover, the embryos from bull C reaching the blastocyst stage cleaved faster (first cleavage at 23.1 � 2.1 hpi vs. 25.4 � 2.7 hpi for bull B; ANOVA: P &lt; 0.05). In a third experiment, 65 to 76 Day 8 blastocysts were sexed per bull. Embryo sexing was performed by PCR using the co-amplification of a Y-specific bovine SRY sequence and an autosomal btRep-137 sequence. Only blastocysts obtained with bull C showed a shift in sex ratio toward male embryos (76.0% male embryos vs. 53.8% for bull B; chi-square test: P &lt; 0.05), whatever the size of the blastocyst. The shift in sex ratio was already present at the 2-cell stage (64.2% male embryos; n = 53; chi-square test: P &lt; 0.05). In conclusion, for 2 out of 4 bulls, a correlation was observed between the kinetics of PN formation, the timing of first cleavage, and the sex ratio of the resulting embryos.


2015 ◽  
Vol 27 (1) ◽  
pp. 211
Author(s):  
E. Ghys ◽  
D. De Troy ◽  
I. Donnay

Male and female pre-implantation bovine embryos may differ in several aspects such as kinetics of development, metabolism, or gene expression. These differences vary between culture conditions and may lead to shifts in sex ratio. In a previous study, we showed that female Day 7 blastocysts display a higher apoptotic rate than male ones when cultured in the presence of 5% FCS (Ghys et al. 2013 Reprod. Fertil. Dev. 25, 194). The difference was less important in the presence of BSA. This previous study was performed on in vitro-produced embryos produced with sexed semen and analysed using confocal microscopy. The objective of the present work is to confirm these differences using a) first, the unsexed semen of the same bull (bull 1) as the one used in the previous study in order to exclude any potential bias induced by the use of sexed semen and b) second, the unsexed semen of another bull (bull 2) in order to generalise our findings to the Bos taurus species. Levels of apoptosis were assessed in Day 7 blastocysts using immunohistochemical staining of cleaved caspase-3 and detection of fragmented DNA by TUNEL reaction on Day-7 blastocysts cultured with 5% FCS. Quantification of the number of stained cells was achieved with a fluorescence microscope. After cell counting, embryos were recovered and sexed by PCR. In both experiments, a higher proportion of cells showing caspase staining was observed in female (n = 145) than in male (n = 215) embryos (Bull 1: male: 11.8 ± 0.6%; female: 17.6 ± 1.1%, 2-way ANOVA, P ≤ 0.0001; bull 2: male: 9.5 ± 0.4%; female: 13.3 ± 0.6%, P ≤ 0.0001), whereas the proportion of TUNEL-stained cells was only significantly higher in female embryos produced with the semen of bull 2 (bull 1: male: 10.8 ± 0.4%; female: 11.4 ± 0.6%, P = 0.12; bull 2: male: 7.2 ± 0.3%; female: 9.1 ± 0.4%, P = 0.0009). A significant difference in cell number was observed between male and female blastocysts produced with the semen of bull 2 (male: 172 ± 5; female: 154 ± 5, P = 0.02) and the same tendency was observed for embryos generated with the semen of bull 1 (male: 143 ± 4; female: 132 ± 4, P = 0.07). In conclusion, our study demonstrated that the use of sexed semen does not interfere with the pattern of caspase and TUNEL staining previously observed. Moreover, a similar pattern was observed with 2 different bulls. We can thus conclude that the level of apoptosis of bovine Day 7 blastocysts produced in the presence of FCS is higher in female than male embryos. This could be related to the tendency towards a lower cell number in female blastocysts and to the shift in sex ratio in favour of male embryos often observed in the presence of serum.


2022 ◽  
Vol 34 (2) ◽  
pp. 281
Author(s):  
A. Fries ◽  
B. Zimmer ◽  
B. Rabenau ◽  
F. Kotarski ◽  
C. Wrenzycki
Keyword(s):  

2005 ◽  
Vol 17 (2) ◽  
pp. 219 ◽  
Author(s):  
C.E. Ferguson ◽  
T.R. Davidson ◽  
M.R.B. Mello ◽  
A.S. Lima ◽  
D.J. Kesler ◽  
...  

There has been much debate over a direct role for progesterone (P4) in early bovine embryo development. While previous attempts to supplement bovine embryos in vitro with P4 produced results that vary and are often contradictory, this may be a response of administering P4 at inappropriate times. Therefore, the objective of these experiments was to determine if P4 could exert a direct effect on developing IVF-derived bovine embryos when administered at an appropriate time of embryo development. In Exp. I, IVF-derived bovine 8-cell embryos were randomly allotted to treatments: (1) control, CR1aa medium (n = 168); (2) vehicle, CR1aa + ETOH (0.01%) (n = 170); and (3) P4, CR1aa + ETOH + P4 (20 ng/mL in 50-μL droplet) (n = 173). In Exp. II, IVF-derived bovine 8-cell embryos were randomly allotted to treatments: (1) control, CR1aa medium (n = 160); (2) vehicle, CR1aa + DMSO (0.01%) (n = 180); and (3) P4, CR1aa + DMSO (0.01%) + P4 (20 ng/mL in 50-μL droplet) (n = 170). All embryos were evaluated on Days 6 to 9 post-insemination and rates calculated from 8-cell embryos. In Exp. I, ETOH tended to have a detrimental effect with significantly fewer (P < 0.05) embryos (53%) developing to the blastocyst stage on Day 7 compared with the control (62%) and P4 (71%) groups. At Day 7, significantly more embryos cultured in P4 (71%) developed to the blastocyst stage compared with the control group (62%). P4 treatment significantly increased the number of Grade 1 blastocysts (25%) on Day 7 compared with vehicle (15%) and control (17%) groups. At the end of culture, there were also significantly more Day 9 hatched blastocysts in the P4 group (33%) compared with vehicle (22%) and control (21%) groups. Supplementing P4 in the culture medium increased the rate of development, resulting in significantly more blastocysts (8%) on Day 6 and hatched blastocysts (21%) on Day 8 compared with vehicle (3% and 12%) and control (0% and 8%) groups, respectively. In Exp. II, there were no significant differences between treatment groups for Day 7 blastocysts (control 54%, DMSO 61%, P4 57%) and Day 9 hatched blastocysts (control 46%, DMSO 51%, P4 46%). However, there were significantly more Grade 1 blastocysts in the P4 group (22% and 36%) on Days 6 and 8 compared with vehicle (11% and 23%) and control (13% and 23%) groups, respectively. The lack of improvement in Day 7 blastocysts and Day 9 hatched blastocysts rates leads to further uncertainty in understanding the P4 vehicle interactions. In conclusion, the results of these two experiments indicate that P4 can exert a direct effect on the developing IVF-derived bovine embryo; however, due to P4 vehicle interactions; other inert vehicles need to be explored to further evaluate the direct effects of P4 on the developing bovine embryo.


2017 ◽  
Vol 3 (2) ◽  
pp. 123
Author(s):  
Dian Novianto ◽  
Budi Nugraha ◽  
Andi Bahtiar

Ikan todak berparuh pendek atau ikan tumbuk atau shortbill spearfish (Tetrapturus angustirostris) merupakan salah satu hasil tangkapan sampingan rawai tuna. Informasi mengenai ikan todak berparuh pendek seperti komposisi ukuran, perbandingan kelamin, dan tingkat kematangan gonadsangat terbatas. Tulisan ini bertujuan untuk menyajikan data dan informasi mengenai aspek biologi ikan todak berparuh pendek yang merupakan hasil tangkapan sampingan dari rawai tuna yang beroperasi di Samudera Hindia. Penelitian ini dilakukan pada bulan September sampai Desember 2008 di perairan Samudera Hindia. Hasil penelitian menunjukan bahwa ikan todak berparuh pendek memiliki kisaran panjang tubuh 135-175 cmLJFL dan modus pada kisaran 155-165 cmLJFL.Perbandingan jenis kelamin ikan jantan dan betina 1:13,5, berdasarkan atas hasil uji chi-square menunjukan bahwa rasio ikan jantan dan betina pada periode penelitian ini tidak seimbang. Pada bulan September ikan todak berparuh pendek betina didominansi oleh tingkat kematangan gonad IIsebesar 66,7%, bulan Oktober oleh tingkat kematangan gonad V sebesar 46,2%, bulan Nopember oleh tingkat kematangan gonad II sebesar 53,3%, sedangkan pada bulan Desember oleh tingkat kematangan gonad III sebesar 42,9%. Pada bulan Nopember sampai Desember terlihat bahwa tingkat kematangan gonad V mulai berkurang, hal ini menunjukan bahwa pada bulan Nopember sampai Desember diduga banyak ikan todak berparuh pendek betina yang sudah memijah. Shortbill Spearfish (Tetrapturus angustirostris) is one of bycatch of tuna longline. Information about shortbill spearfish on the size composition, sex ratio, and maturity stage is still very limited. The objective this paper is to present the data and information about shortbill spearfish which is a bycatch of tuna longline that operated in the Indian Ocean. Research was conducted during September until December 2008 in Indian Ocean. The results showed that the shortbill spearfish have body length about 135-175 cmLJFL and modes in 155-165 cmLJFL. Sex ratio of the male and female was 1:13.5. Based on chi-square test showed that the ratio of male and female in the period of the study was not balanced. In September, the female stage maturity was dominated by level II of 66.7%, October by level V of 46.2%, November by level II of 53.3%, and December by level III of 42.9%. During November until December showed that the maturity stage of level V was decreased, this shows that in this time the female of shortbill spearfish was spawned.


2004 ◽  
Vol 16 (2) ◽  
pp. 213 ◽  
Author(s):  
J. Small ◽  
M. Colazo ◽  
D. Ambrose ◽  
R. Mapletoft ◽  
J. Reeb ◽  
...  

The objective was to evaluate the effect of pLH treatment on pregnancy rates in recipients receiving in vivo- or in vitro-produced bovine embryos. Heifers (n=37) and lactating (n=28) and non-lactating (n=150) beef cows were treated at random stages of the cycle with 100μg GnRH i.m. (Cystorelin, Merial Canada Inc., Victoriaville, Quebec, Canada) on Day −9, 500μg cloprostenol i.m. (PGF; Estrumate, Schering Plough Animal Health, Pointe-Claire, Quebec, Canada) on Day —2 and GnRH on Day 0 (66h post-PGF; without estrus detection). Cattle were placed at random, by class, into three groups: no further treatment (Control; n=71), or 12.5mg pLH (Lutropin-V, Bioniche Animal Health, Belleville, Ontario, Canada) on Day 5 (n=72) or on Day 7 (n=72) after the second GnRH. On Day 7, cattle with a CL &gt;10mm in diameter (determined ultrasonically) received in vivo-produced, fresh (Simmental) or frozen (Holstein), or in vitro-produced frozen (Holstein) embryos (embryo type balanced among groups). Embryos were cryopreserved in 10% ethylene glycol; in vivo-produced frozen embryos were thawed 5 to 10s in air, 15s in a water-bath at 30°C and then “direct-transferred” nonsurgically. In vitro-produced frozen embryos (donated by IND Lifetech Inc., Delta, British Columbia, Canada) were thawed in a water-bath at 27°C for 10s and placed in ViGro Holding Plus medium (AB Technology, Pullman, WA, USA) at room temperature, evaluated and then transferred nonsurgically. Pregnancy was determined by ultrasonography on Day 35. Data were analyzed with CATMOD, chi-square and GLM procedures (SAS Institute, Cary, NC, USA.). Twenty cattle (9.3%) did not receive embryos; five heifers had cervical problems, and five heifers and 10 cows did not have a CL &gt;10mm. Overall, 7.1% of the recipients had two CL on the day of embryo transfer. There was no effect (P&gt;0.05) of treatment, embryo type (or interaction) or class of recipient on pregnancy rate (overall, 44.1%, 86/195; Table 1). Similarly, mean (±SD) CL diameter and luteal area did not differ (P&gt;0.05) among groups or between pregnant and open recipients (overall, 22.0±3.4mm and 352.0±108.7mm, respectively). However, recipients with a CL diameter ≥18mm tended (P&lt;0.1) to have a higher pregnancy rate (45.8 vs 25.0%). In a subset of 40 recipients examined ultrasonically on Day 12, 50% of those treated on Day 5 and 70% of those treated with pLH on Day 7 had two CL. In summary, overall pregnancy rate in GnRH-synchronized recipients receiving in vitro- or in vivo-produced embryos by nonsurgical transfer was 44.1%. Embryo survival to Day 35 was not affected by type of embryo or treatment with pLH 5 or 7 days after ovulation. Table 1 Pregnancy rate in recipients on Day 35 based on pLH treatment and embryo-type


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