11 Effect of breed type on production of bovine embryos: Experience in Paraguay

2021 ◽  
Vol 33 (2) ◽  
pp. 113
Author(s):  
C. Arreseigor ◽  
F. Arza-Spinzi ◽  
P. Sanchez ◽  
J. A. Berdugo ◽  
J. L. Konrad ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Embryo Production ◽  
Production Program ◽  
Significance Level ◽  
Breed Type ◽  
Bull Semen ◽  
Follicular Aspiration ◽  
Chi Squared ◽  
Post Hoc

One of the parameters that has the most influence on invitro embryo production programs is the number of oocytes obtained in each follicular aspiration session (ovum pickup; OPU). A significant impact of the breed of the donor on this parameter has been reported. The objective of this work was to compare the parameters of an invitro embryo production program of cows of different breeds in Paraguay. A total of 4811 OPU sessions were performed between 2016 and 2019 in cows classified according to breed and type. Beef-type breeds: Nelore (Bos indicus): n=1569; Aberdeen Angus (Bos taurus): n=1276; and Brangus (Cross): n=182 OPU, and Gyr (Bos indicus): n=1086; dairy breeds: Holstein (Bos taurus): n=401, and Girolando (Cross): n=297. The oocytes were aspirated and transported to the same laboratory located in Asunción, Paraguay. The invitro embryo production protocol was similar in all types. Bull semen tested for IVF was used. The number of oocytes, percentage viability, and percentage embryo production were evaluated. Additionally, the mean and standard deviation of the variables were calculated to show the efficiency of the processes, according to the production aptitude of the donors (meat or milk) and the breed type (Bos indicus, Bos taurus, or crosses). Continuous data were analysed with ANOVA and Tukey’s post hoc comparisons. Categorical data were analysed using Chi-squared at a significance level of 0.05. In this work, the production aptitude had no significant effect over the studied variables. However, some significant differences were found considering the breed type of the oocyte donor cow, as shown in Table 1. When crosses with the pure breeds are compared with their crosses, we found that Brangus produced more pregnancies and a greater number of oocytes/OPU compared with Angus (P<0.05). When the same comparison was made between Girolando and Holstein, no significant differences were found. The results show that Bos indicus breeds and their crosses have a greater capacity to produce more oocytes and embryos and that Bos indicus and crossbreeds were more efficient in producing pregnancies (2-fold) per OPU session than Bos taurus breeds. Additionally, crossing with meat indicus breeds generates better quality embryos and increases efficiency in the system of embryo production. Table 1. Comparison of embryo production parameters Item Breed type Bos indicus Cross Bos taurus Oocytes/OPU (mean±SD) 29.8±2.7a 26.3±7.8a 14.6±1.4b Viable oocytes, % 64.7±3a 64.6±3.4a 60.1±3.1a Embryo produced/OPU, % 35.2±4.7a 32.8±9.4a 26.2±4a Embryo/OPU 6.9±1.7a 5.4±1.7a 2.3±0.4b Pregnancy rate, % 29.6±5.5a 33.1±6.3a 25.3±5a Pregnancies/OPU 2.1±0.9a 1.9±1a 0.6±0.2b a,bValues within a row different letters differ (P<0.05).

Embryo production in middle-aged and mature Bos taurus × Bos indicus cows induced to multiple ovulation in a tropical environment

2019 ◽  
Vol 51 (8) ◽  
pp. 2641-2644
Author(s):  
Fernando Naranjo-Chacón ◽  
Felipe Montiel-Palacios ◽  
Rodolfo Canseco-Sedano ◽  
Concepción Ahuja-Aguirre
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Tropical Environment ◽  
Middle Aged ◽  
Embryo Production ◽  
Multiple Ovulation

257 DIFFERENCES BETWEEN BOS TAURUS AND BOS INDICUS EMBRYOS: TRANSCRIPTS AMOUNTS

2010 ◽  
Vol 22 (1) ◽  
pp. 285
Author(s):  
S. Wohlres-Viana ◽  
M. M. Pereira ◽  
A. P. Oliveira ◽  
J. H. M. Viana ◽  
M. A. Machado ◽  
...  
Keyword(s):  
Production System ◽  
Production Systems ◽  
Bos Taurus ◽  
Bos Indicus ◽  
In Vitro Production ◽  
Embryo Production ◽  
Peroxiredoxin 1 ◽  
Vitro Production

The Zebu breeds (Bos indicus) are different from European breeds (Bos taurus) in some aspects of their reproductive physiology, including follicle recruitment, number of follicular waves, and oocyte ultrastructure. On the other hand, embryos produced in vivo and in vitro show morphological and developmental differences, which can be related to culture environment. The aim of this study was to evaluate the effect of breed (Gyr v. Holstein) within embryo production system (in vivo and in vitro), as well as effect of production systems within breeds on relative abundance of transcripts related to formation, survival, and subsequent development of blastocysts, such as those involved in water and small solutes transport (Aquaporins 3 and 11), blastocoel formation (Na+/K+-ATPase a1 and |52), and cellular stress response (Peroxiredoxin 1). For in vivo embryo production, donors were superstimulated with FSH and inseminated, and embryos were recovered 7 days after AI. For in vitro embryo production, oocytes recovered by ovum pickup were in vitro matured and fertilized and then cultured for 7 days in culture medium under 5% CO2 at 38.5°C. For each group, blastocysts (n = 15) distributed in 3 pools were used for RNA extraction (RNeasy MicroKit, Qiagen, Valencia, CA, USA), followed by RNA amplification (Messageamp II amplification kit, Ambion-Applied Biosystems, Foster City, CA, USA) and reverse transcription (SuperScript III First-Stand Synthesis Supermix, Invitrogen, Carlsbad, CA, USA). The cDNA were submitted to real-time PCR, using the H2a gene as endogenous control, and analyzed by REST© software. To evaluate breed effect within the production systems, 2 comparisons were performed: (1) in vivo: Gyr v. Holstein and (2) in vitro: Gyr v. Holstein, considering Holstein data as 1.00. To evaluate production system effect within breeds, 2 comparisons were performed: (1) Gyr: in vivo v. in vitro and (2) Holstein: in vivo v. in vitro, considering in vivo produced embryo data as 1.00. The results are shown as mean ± SEM. For in vivo comparison between breeds, Aquaporin 3 (1.66 ± 0.77), Na+/K+-ATPase a1 (1.61 ± 0.56), and Peroxiredoxin 1 (1.61 ± 0.66) were up-regulated (P < 0.05) in Gyr embryos when compared with Holstein embryos, whereas for in vitro comparison, no differences (P > 0.05) were found. For comparisons between production systems within breeds, only Peroxiredoxin 1 (0.31 ± 0.39) was down-regulated (P < 0.01) in in vitro produced Gyr embryos when compared with in vivo counterparts. No differences (P > 0.05) were found between production systems for the Holstein breed. In conclusion, these data suggest that there is a difference on gene expression between Bos taurus and Bos indicus blastocysts, but such difference between breeds can be attenuated by the in vitro production system, indicating an embryo adaptation to the in vitro culture conditions. The data also suggest that the in vitro production system can influence the amount of transcripts in Gyr embryos. Other genes should be evaluated for a better understanding of these differences. Financial support was provided by CNPq and FAPEMIG.

347 COULD THE DIFFERENTIAL EXPRESSION OF LUTEINIZING HORMONE RECEPTOR ISOFORMS EXPLAIN THE VARIABILITY IN SUPEROVULATORY RESPONSES IN CATTLE?

2015 ◽  
Vol 27 (1) ◽  
pp. 261
Author(s):  
S. Wohlres-Viana ◽  
E. K. N. Arashiro ◽  
J. G. V. Grazia ◽  
L. S. A. Camargo ◽  
M. A. Machado ◽  
...  
Keyword(s):  
Rna Extraction ◽  
Bos Indicus ◽  
Luteinizing Hormone Receptor ◽  
Poor Responders ◽  
Embryo Production ◽  
Lh Receptor ◽  
Follicular Wave ◽  
Follicular Aspiration ◽  
Receptor Isoforms

Embryo production in vivo is highly variable among donors. The Gir breed (Bos indicus) is well known to show a low embryo production after superovulation (2.5 to 3.5 viable embryos per flush), and a high variance in superovulatory responses, which makes this breed an interesting model to study this trait. The aim of this study was to evaluate the expression pattern of LHR isoforms in Gir heifers previously characterised as good (10.3 ± 1.2 embryos/flush, N = 5) or poor (1.1 ± 0.3 embryos/flush, N = 5) responders to superovulation protocols. In both groups, an adapted ultrasound-guided follicular aspiration system (Arashiro et al. 2012 Reprod. Fertil. Dev. 24, 175) was used to collect granulosa cells (GC) from 8-mm follicles growing in either a synchronized but not stimulated follicular wave (FW) or in the fourth day of superovulation (SOV), induced with 200 UI of FSHp (Pluset, Serono). The recovered follicular fluid was centrifuged and the cells were washed with NaCl 0.9% saline and kept in RNA Later (Ambion, Austin, TX, USA). Total RNA extraction was performed using the commercial RNeasy Micro Kit (Qiagen, Valencia, CA, USA). The RNA samples were quantified and reverse transcribed using the commercial Superscript III kit (Invitrogen, Carlsbad, CA, USA). Complementary DNA samples were amplified through real-time PCR, using a LH receptor primer – not selective for LHR isoforms (total LHR) – and 4 sets of isoform selective primers (S1, S10, S10+11, and S11). All samples were previously tested for theca cell contamination through detection of CYP17A1 gene, and those showing contamination were excluded. The β-actin gene was used as endogenous control. Analyses were performed using the REST software and the expression values are shown as mean ± s.e.m. For comparisons between good and poor responders, the first was set as 1.00. For comparisons between FW and SOV, FW was set as 1.00. In the good responder group, there was no difference (P > 0.05) in total LHR expression among GC samples from FW and SOV. However, the S10+11 isoform was down-regulated (0.4 ± 0.1; P < 0.01) after SOV. In the poor responders group, total LHR expression was down-regulated (0.2 ± 0.1; P < 0.01) after SOV, but there was no difference in the expression of isoforms (P > 0.05). Contrasting the response groups (good and poor), total LHR (15.1 ± 7.6; P < 0.001), and the isoforms S10 (5.7 ± 2.7; P < 0.01), S10+11 (1.9 ± 0.6; P < 0.01), and S11 (5.1 ± 2.5; P < 0.01) were up-regulated in FW of poor responders, but there was no difference (P > 0.05) in any LHR form during SOV. We concluded that 1) LHR expression is different between heifers characterised as good or poor responders to superovulation; 2) superovulation modulates the LHR expression and reduces the original differences observed in unstimulated cycles; 3) diminished expression of total LHR, but not in the isoforms, in poor responders heifers could suggest a reduction in the expression of full-length LHR, with possible consequences to ovulatory capability after superovulation.Financial support was provided by CNPq Project 477701 and Fapemig PPM 0067/11.

179 COMPARISON OF OOCYTE AND EMBRYO PRODUCTION AMONG BOS TAURUS, BOS INDICUS, AND INDICUS-TAURUS DONOR COWS

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 ◽  
...  
Keyword(s):  
High Efficiency ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Cumulus Cells ◽  
Holstein Cows ◽  
Embryo Production ◽  
Total N ◽  
The Mean ◽  
Donor Cows

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.

scholarly journals Effects of a high-energy diet on oocyte quality and in vitro embryo production in Bos indicus and Bos taurus cows

2015 ◽  
Vol 98 (5) ◽  
pp. 3086-3099 ◽  
Author(s):  
J.N.S. Sales ◽  
L.T. Iguma ◽  
R.I.T.P. Batista ◽  
C.C.R. Quintão ◽  
M.A.S. Gama ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Oocyte Quality ◽  
High Energy ◽  
Embryo Production ◽  
In Vitro Embryo Production

225 ADDITION OF EQUINE CHORIONIC GONADOTROPIN TO A TRADITIONAL FOLLICLE STIMULATING HORMONE PROTOCOL FOR SUPEROVULATION OF BOS TAURUS BEEF COWS

2012 ◽  
Vol 24 (1) ◽  
pp. 224 ◽  
Author(s):  
R. L. Davis ◽  
A. Arteaga ◽  
J. F. Hasler
Keyword(s):  
Treatment Group ◽  
South America ◽  
Bos Taurus ◽  
Animal Health ◽  
Bos Indicus ◽  
Treatment Protocol ◽  
Beef Cows ◽  
High Response Rate ◽  
Control Group ◽  
Embryo Production

This study examined the superovulatory responses of Bos taurus beef cows maintained in a commercial embryo transfer facility. Donors were superovulated 1 to 3 times each with either a traditional 8 injection FSH protocol (controls, n = 126) or 6 injections of FSH with the seventh or eighth FSH treatments replaced by 2 injections of eCG (treatment, n = 134). During the 5-month study, 132 donors were alternatively assigned to a control or treatment group for a single superovulation and an additional 62 animals were superovulated 2 (n = 58) or 3 times (n = 4) in a crossover design. Although 14 beef breeds were represented in the study, 87% of the cows were Angus, Red Angus, Polled Hereford, or Charolais. All donors were synchronized on Day 0 with a CIDR, 5 mg of oestradiol-17β and 100 mg of progesterone. Starting on Day 4 (p.m.), controls were injected twice daily for 4 days with descending doses of porcine FSH (Folltropin-V®, Bioniche Animal Health, Belleville, Ontario, Canada). Cows received 750 μg of cloprostenol (Estrumate®, Intervet Schering-Plough, Summit, NJ, USA) at the seventh FSH injection and the CIDR was removed at the eighth FSH injection. Based on previous experience with specific, individual animals, total FSH dose per donor ranged from 240 to 400 mg. However, 74% of treatments involved 380 mg for controls and 310 mg for treated donors that received eCG. In addition, donors that were superovulated more than once received the same FSH dose in the crossover, treatment-control design. In the treatment group, 200 IU of eCG (Pregnecol™ 6000, Bioniche Animal Health) was substituted for the seventh and eighth FSH injections. Inseminations were conducted on a timed AI basis, with one unit of semen 32 h and a second 48 h following CIDR removal. Results were analysed by ANOVA as shown in Table 1. Although more ova/embryos and unfertilized ova (UFO) were recovered in the control group, the control and treatment groups did not differ in the number of grade 1, 2, or 3 embryos or in the number of degenerate embryos. Previous superovulation studies in South America using eCG to replace the last 2 injections of FSH resulted in more total ova/embryos in Nelore cows but not heifers and in more embryos in Brangus and Sindhi cows. The mean embryo production for the control cows in this study was high and the addition of eCG in the protocol did not improve embryo production. Failure of eCG to increase the number of embryos for Bos taurus cows in this study compared with previous studies may be due to differences with Bos taurus versus Bos indicus breeds or differences in management factors between Canada and South America. The high response rate in the controls may also have contributed to the failure of any advantage of adding eCG to the treatment protocol. Table 1.Mean numbers (± SEM) of ova and embryos recovered from Bos taurus females superovulated with 2 different protocols

402 SUPEROVULATION OF TROPICAL-ADAPTED BOS TAURUS AND BOS INDICUS COWS IN A TROPICAL ENVIRONMENT

2010 ◽  
Vol 22 (1) ◽  
pp. 357
Author(s):  
R. H. Alvarez ◽  
A. C. Martinez ◽  
R. M. L. Pires
Keyword(s):  
Ovarian Function ◽  
Bos Taurus ◽  
Animal Health ◽  
Bos Indicus ◽  
Ovarian Response ◽  
Estradiol Benzoate ◽  
Maximum Temperature ◽  
Embryo Production ◽  
Chi Square ◽  
Average Maximum

Breed differences in ovarian function were found among beef Bos indicus and Bos taurus cows maintained in a subtropical environment (Alvarez P et al. 2000 J. Anim. Sci. 78, 1291-1302). The aim of this study was to compare ovarian response to superovulation and embryo production of tropical-adapted Bos taurus and Bos indicus cows. The experiment was carried out in a tropical wet climate at the experimental station of Instituto de Zootecnia (latitude 22°46′S, longitude 47°17′W) from November to February (average maximum temperature = 30.0 ± 0.8°C and average absolute precipitation = 153.1 ± 78.8 mm3). Forty Caracu (a local Bos taurus breed) and 50 Nelore (Bos indicus breed) lactating cows were treated with an intravaginal device containing progesterone (1.38 mg; CIDR-B®, Pfizer Animal Health, Montreal, Québec, Canada) and 2.5 mg i.m. of estradiol benzoate (Estrogin®, Farmavet, São Paulo, Brazil). Four days later, the animals were superovulated with multiple i.m. injections of 400 IU of FSH (Pluset®, Calier, Spain) in decreasing doses (75-75, 75-50, 50-25, and 25-25 IU) at 12-h intervals over 4 days. The CIDR-B® device was removed 3 days after the first superovulatory injection and cows received i.m. 150 μg of cloprostenol (Veteglan®, Calier, Spain). Cows were inseminated 48 and 62 h after the cloprostenol injection and embryos were recovered nonsurgically 7 days after insemination. Differences in the number of CL (assessed by ultrasound scanning), total number of ova/embryos, and number of transferable embryos were analyzed by ANOVA. Differences in the number of animals with low response (<3 CL) to superovulation were analyzed by chi-square test. All donors (with the exception of 1 Caracu and 2 Nelore) with ovarian response >3 CL showed estrus at insemination. Three (8.9%) Caracu and 5 (10.0%) Nelore cows had <3 CL following the superovulation treatment (P = 0.68). There was no difference (P > 0.05) in the mean (± SEM) CL counts of Caracu (11.4 ± 3.3) and Nelore (12.0 ± 4.1) cows. Similarly, there were no differences (P > 0.05) between Caracu and Nelore cows for total number of ova/embryos collected (8.6 ± 2.6 v. 9.0 ± 4.3) or transferable embryos (6.0 ± 2.4 v. 5.1 ± 2.9). In conclusion, the superovulation of Caracu and Nelore cows carried out in a tropical climate resulted in similar ovarian responses and embryo production. Supported by FAPESP.

72 Invitro embryo production using prepubertal calf oocytes with conventional semen and sexed semen ULTRA-4M

2020 ◽  
Vol 32 (2) ◽  
pp. 162
Author(s):  
A. Velazquez ◽  
H. Alvarez ◽  
M. Kjelland ◽  
F. Villaseñor ◽  
G. Ariza ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Sperm Concentration ◽  
Reproductive Potential ◽  
The United States ◽  
Field Trials ◽  
Cleavage Rate ◽  
Embryo Production ◽  
Sexed Semen ◽  
Α Level

Invitro embryo production (IVP) can increase the reproductive potential and genetic quality of cattle, as well as other species. This powerful assisted reproduction tool can be used to produce embryos from prepubertal calves, reducing the generation interval. A recent sexed semen technology known as ULTRA (ST Genetics), completely modified the technique, the media and sperm concentration. In field trials with AI there was no difference between conventional semen (CONV) and ultra-sexed semen at a concentration of 4 million per straw (ULTRA-4M). The combined use of IVP and ULTRA-4M can decrease the selection time for improving dairy and beef cattle herd genetics. The objective of this research was to compare the CONV and ULTRA-4M semen using bovine IVP and prepubertal calves. The research was carried out in the reproduction laboratory of the Facultad de Estudios Superiores Cuautitlán - Universidad Nacional Autónoma de México (FESC-UNAM). The IVP was performed with a continuous invitro culture (IVC) system. The ovaries were collected in Campeche, México, from Bos indicus×Bos taurus crossbred calves (6 months old) using surgical castration (for export to the United States) and transported to the laboratory (FESC-UNAM) in BO-HEPES-IVM (Bioscience™), in an oocyte transporter (WTA). Vitrogen media were used for IVF and IVC. For IVM, the cumulus-oocyte complexes (COCs) were selected (only grades 1 and 2) and matured for 24h at 38.5°C. Matured oocytes (n=600, divided equally into five replicates) were divided into 2 groups, the CONV group and the ULTRA-4M group. The IVF process was conducted with CONV and ULTRA-4M semen from the same bull (Holstein) at a concentration of 2×106 and 0.5×106 spermatozoamL−1, respectively, for 18h in 38.5°C, 5% CO2, 95% air, and 100% humidity. The presumptive zygotes were denuded by pipetting and set in IVC until Day 7 at 38.5°C, 5% CO2, 5% O2, and 90% N2 at 100% humidity. The cleavage results were recorded 56h after the beginning of IVC. The cleavage rate, embryos with more than 6 cells, and blastocysts on Day 7 of culture were evaluated. The statistical analysis was carried out with the GLM procedure of the SAS software (version 9.3; SAS Institute Inc.) to evaluate the results of CONV vs. ULTRA-4M (α level=0.05). The percentage of cleavage for CONV was 46%±1.4 and 43.2%±1.4 for ULTRA-4M. The results for embryos with more than 6 cells in the CONV and ULTRA-4M groups were 16%±0.6 and 14%±0.6, respectively. The percentage of blastocysts on Day 7 for CONV was 9%±0.6 and 8%±0.6 for ULTRA-4M. There were no significant differences between groups (P&gt;0.05) for all variables analysed. In conclusion, under the conditions of this research the ULTRA-4M and CONV produced similar results for IVP.

scholarly journals 34 Reproductive management of beef females in tropical and sub-tropical environments

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 37-37
Author(s):  
Nicola Oosthuizen ◽  
Pedro Levy Piza Fontes ◽  
G Cliff Lamb
Keyword(s):  
Assisted Reproductive Technologies ◽  
Bos Taurus ◽  
Management Strategies ◽  
Bos Indicus ◽  
The United States ◽  
Reproductive Technologies ◽  
Pregnancy Rates ◽  
Embryo Production ◽  
Reproductive Management

Abstract Bos indicus and Bos taurus cattle diverged from an evolutionary standpoint more than 110,000 years ago. Since then, Bos indicus cattle have undergone genetic adaptations beyond the commonly discussed increased thermo-tolerance and parasite resistance. Several physiological differences exist between Bos indicus and Bos taurus cattle, and it is important to consider these differences when establishing reproductive management strategies. It has been well described that Bos indicus cattle have a delayed onset of puberty and longer periods of postpartum anestrus, yet through the utilization of estrus synchronization protocols these challenges can be attenuated. However, when Bos indicus females are exposed to these protocols, they are known to have smaller dominant follicles, lower expression of estrus, and decreased pregnancy rates to artificial insemination (AI) when compared to Bos taurus females. These factors can be overcome through the utilization of estradiol and progesterone based synchronization protocols, which improve follicular dynamics and yield acceptable pregnancy rates to assisted reproductive technologies in cattle adapted to tropical or subtropical conditions. However, the use of estrogens for synchronization purposes is not permitted in the United States, and cattle producers need to rely on GnRH-based protocols. Another key difference between subspecies, is that Bos indicus females have greater antral follicle counts than Bos taurus females, which proves beneficial for in vitro embryo production. Therefore, an opportunity exists to explore the greater productivity of donors in embryo production in order to improve genetics in herds that utilize these breeds.

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