105 Optimization of a five-day fixed-time embryo transfer program in dairy heifers: Use of gonadotrophin-releasing hormone at initiation of the protocol

2020 ◽  
Vol 32 (2) ◽  
pp. 179
Author(s):  
R. Sala ◽  
L. Carrenho-Sala ◽  
V. Absalon-Medina ◽  
A. Lopez ◽  
M. Fosado ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Pregnancy Loss ◽  
Fixed Time ◽  
Transfer Program ◽  
Releasing Hormone ◽  
Utilisation Rate ◽  
Stage Embryo ◽  
Gonadotrophin Releasing Hormone ◽  
Using Data ◽  
Synchronization Protocol

Optimized fixed-time embryo transfer (FTET) protocols for synchronization of recipients have the potential to improve the overall efficiency and profitability of embryo transfer (ET) programs. The objective of the present study was to evaluate the effect of dose of gonadotrophin-releasing hormone (GnRH) at initiation of a 5-day synchronization protocol for FTET. Holstein heifers (n=2689) at two locations were synchronized using a 5-day CO-Synch protocol as follows: Day 0: CIDR inserted, Day 5: CIDR removed, prostaglandin (PG)F2α treatment (500μg cloprostenol), Day 6: PGF2α treatment, Day 8: GnRH (100μg of gonadorelin). On Day 0, at the time of CIDR insertion, heifers were assigned in a completely randomised design to the following groups: Single (a single dose of GnRH; 100μg of gonadorelin), Double (200μg of gonadorelin) or No GnRH (control). All heifers received an Estrotect patch placed on Day 5 and evaluated for signs of oestrus on Day 8. At location A, heifers were evaluated by ultrasonography 5 days after GnRH to determine presence and size of corpus luteum (CL), whereas at location B presence and location of CL were determined by transrectal palpation at the time of transfer. Heifers with a CL received an embryo 7±1 days after GnRH administration, and pregnancy was determined by ultrasonography 41 and 63 days after GnRH. Data were analysed by generalized linear mixed models. Oestrus expression was greater in heifers that received Single and Double GnRH than in the No GnRH group (P=0.001). Similarly, utilisation rate (number transferred per number treated) was greater for heifers in the Single and Double GnRH group than for those in the No GnRH group (P=0.02). Pregnancy data were analysed for a subset of recipients using data from Day 41 (n=2267) and Day 63 (n=2042). The analysis of fertility outcomes included as covariates the type of embryo (invitro fresh or frozen and invivo fresh or frozen), embryo stage, embryo quality, interval from GnRH to transfer, and oestrus expression. Pregnancies per embryo transfer (P/ET) at Days 41 and 63 were not different between treatment groups (P=0.86), and there was no interaction between type of embryo and treatment (P>0.15). Pregnancy loss between Days 41 and 63 was not different (P=0.49) between treatments groups. In conclusion, the removal of the initial GnRH from a 5-day FTET protocol resulted in a slight but significant reduction in the utilisation rate and the percentage of heifers showing oestrus. However, there was no detrimental effect on fertility. As a result, the overall cost of the FTET program can be reduced by eliminating the need for the initial GnRH treatment without compromising fertility. Table 1.Reproductive performance in recipients receiving different doses of gonadotrophin-releasing hormone (GnRH) at initiation of the synchronization protocol Treatment Oestrus (n) Utilisation rate (n) P/ET1 D41 (n) P/ET D63 (n) Pregnancy loss (n) No GnRH 69.2%B (621/898) 85.0%B (763/898) 41.6% (308/740) 39.9% (268/672) 4.3% (12/280) Single GnRH 76.1%A (685/900) 88.8%A (799/900) 42.7% (329/770) 39.5% (272/689) 6.5% (19/291) Double GnRH 75.3%A (671/891) 88.7%A (790/891) 41.5% (314/757) 38.9% (265/681) 5.4% (15/280) A,BValues with different superscripts within a column differ (P<0.05). 1P/ET=pregnancies per embryo transfer.

101 Treatment with gonadotrophin-releasing hormone on Day 7 or 21 does not reduce pregnancy loss in dairy heifers receiving invitro-produced embryos

2020 ◽  
Vol 32 (2) ◽  
pp. 176
Author(s):  
B. J. Duran ◽  
R. V. Sala ◽  
P. L. J. Monteiro ◽  
C. Gamarra ◽  
M. Fosado ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Pregnancy Loss ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
P Value ◽  
Releasing Hormone ◽  
Dairy Heifers ◽  
Condition Score ◽  
Pregnancy Status ◽  
Gonadotrophin Releasing Hormone

Previous research has shown that induction of an accessory corpus luteum (CL) by administration of gonadotrophin-releasing hormone (GnRH) on Day 5 increases circulating progesterone and reduces pregnancy loss between Days 33 and 60 in heifers receiving invitro-produced (IVP) embryos. Therefore, the objective of the present study was to determine whether timing of induction of an accessory CL influenced pregnancy loss in IVP recipients. Holstein heifers (n=1,658) were synchronized using a modified 5-day CIDR CO-Synch protocol. Briefly, heifers received an intravaginal progesterone device (CIDR) on Day −8, Day −3: CIDR removed and first prostaglandin F2α (PGF2α) treatment, Day −2: second PGF2α, and Day 0: GnRH (G1, 100µg of gonadorelin acetate). Oestrus expression was evaluated on Day 0 with the use of an oestrus detection device. Transfer of fresh IVP embryos was performed on Day 7±1 after G1. At the time of transfer, heifers were randomly assigned, in a 2×2 factorial design, to receive GnRH (200µg of gonadorelin acetate) or remain as Control (untreated) at two different times: Day 7 (time of embryo transfer (ET)) or Day 21. Thus, the following groups were formed: Control-Control (n=410); Control-GnRH (n=409); GnRH-Control (n=419); and GnRH-GnRH (n=420). All heifers were evaluated by transrectal ultrasonography to determine number, size, and location of CL on Days 5, 14, 21, 28, 32, and 60 and pregnancy status on Days 28, 32, and 60. Data collected from each heifer included embryo stage and quality, oestrus expression, body condition score, number of transfers, and technician. Pregnancies per embryo transfer (P/ET) and pregnancy loss data were analysed by logistic regression (SAS 9.4). Ovulation to Day 7 treatment was greater (P<0.01) in GnRH treated heifers (70.0%; 585 out of 836) than in untreated Controls (2.7%; 22 of 819). Ovulation to Day 21 treatment was determined only in animals pregnant at Day 28 and was greater (P<0.01) in heifers treated with GnRH (37.6%; 153 of 407) than in untreated controls (1.0%; 4 of 390). There was no effect of Day 7 treatment (P>0.68) or Day 21 treatment (P>0.18), nor a Day 7×Day 21 treatment interaction (P>0.48) on P/ET at Day 32 or 60 (Table 1). Treatment with GnRH on Day 7 or 21 did not alter pregnancy loss between Days 32 and 60 (P>0.10). Heifers with an accessory CL present at Day 32 (11.7%; 41 of 350) had similar (P=0.55) pregnancy loss compared with heifers with no accessory CL (14.4%; 54 of 375). The number of CL present on Day 32 did not affect (P=0.23) pregnancy loss; however, heifers with 3 CL (4.9%; 3 of 61) tended (P<0.10) to have reduced pregnancy loss compared with heifers with 1 CL (14.4%; 54 of 375) or 2 CL (13.2%; 38 of 289). In conclusion, treatment with GnRH on Day 7 or 21 induced an accessory CL; however, it did not affect P/ET on Days 32 or 60 and pregnancy loss. Table 1.Pregnancies per embryo transfer (P/ET) and pregnancy loss in embryo recipients based on timing of treatment with gonadotrophin-releasing hormone (GnRH) Treatment P/ET Day 32% (n) P/ET Day 60% (n) Pregnancy loss% (n) Day 7 Day 21 Control Control 42.4 (410) 36.1 (410) 15.0 (174) GnRH 46.0 (409) 40.7 (409) 11.7 (188) GnRH Control 43.7 (419) 36.8 (419) 15.9 (183) P-value GnRH 43.1 (420) 38.8 (420) 10.0 (181) Day 7 treatment 0.68 0.72 0.96 Day 21 treatment 0.51 0.18 0.11 Interaction 0.48 0.66 0.71

104 SOFaaci-HEPES or holding media can be used for embryo loading without changes in pregnancies per embryo transfer nor pregnancy loss in an invitro-produced embryo transfer program

2020 ◽  
Vol 32 (2) ◽  
pp. 178
Author(s):  
D. Pereira ◽  
D. Moreno ◽  
R. Sala ◽  
L. Carrenho-Sala ◽  
M. Fosado ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Fixed Effects ◽  
Pregnancy Loss ◽  
Embryo Quality ◽  
Prostaglandin F2α ◽  
P Value ◽  
Transfer Program ◽  
Embryo Viability ◽  
Stage Embryo ◽  
Embryo Stage

Time elapsed between removal from culture and embryo transfer (ET) can have a profound effect on the success of an invitro-produced (IVP) ET program. The embryo culture medium provides the necessary nutrients for embryo development and the use of media with a different nutrient composition to load embryos into straws could negatively affect embryo viability. The objective of the present study was to evaluate the effect of type of media used for embryo loading on pregnancy establishment and maintenance. Holstein heifers (n=800) were synchronized using a modified 5-day CO-Synch + controlled internal drug release (CIDR) as follows: Day −8: CIDR inserted, Day −3: CIDR removed, prostaglandin F2α treatment (500μg cloprostenol sodium), Day 0: gonadotrophin-releasing hormone (GnRH; 100μg of gonadorelin acetate). Five days after GnRH, heifers were evaluated by ultrasonography to determine presence of a corpus luteum (CL). Embryos were removed from culture on Day 7 (Day 0=fertilization), placed into tubes containing SOFaaci, and transported in an incubator (LabMix, WTA) to the transfer facility within 1.5h. Upon arrival embryos were removed from transport tubes and randomly assigned to be loaded into 0.25-mL straws containing either holding media (Vigro Holding Plus) or SOFaaci-HEPES. After loading into straws, embryos were placed in an ET gun and AI gun warmers set at 35°C until transfer by 1 of 5 technicians. Heifers with a CL were randomised for transfer of a fresh IVP embryo loaded into a straw containing either holding media or SOFaaci-Hepes on Day 7±1. Interval from embryo loading to transfer ranged from 1 to 3h. Pregnancy was determined by ultrasonography on Days 32 and 60. Data were analysed by logistic regression and included the fixed effects of loading media, embryo stage, embryo quality, interval between GnRH and ET, and biologically relevant interactions. Pregnancies per ET (P/ET) on Day 32 were not different between the groups in which embryos were loaded using holding media and those which used SOFaaci-Hepes, nor there were interactions between loading medium and embryo stage, embryo quality, or interval from GnRH to ET (P>0.10; Table 1). Pregnancies per ET (P/ET) on Day 60 were not different between the loading media groups, nor were there interactions between loading medium, embryo stage, and embryo quality, or interval from GnRH to ET (P>0.10). Pregnancy loss between Days 32 and 60 was not different between groups, nor there were interactions between loading media groups and any other factor (P>0.10). In conclusion, the use of either holding medium or SOFaaci-HEPES for fresh IVP embryo loading does not affect fertility; thus, both are suitable alternatives for loading of embryos into transfer straws. Table 1.Pregnancies per embryo transfer (P/ET) and pregnancy loss in recipient heifers transferred with fresh invitro-produced embryos, using either holding medium or SOFaaci-HEPES medium for loading Item P/ET Day 32 (n) P/ET Day 60 (n) Pregnancy loss (n) Loading medium Holding 47.0% (186/396) 41.3% (163/395) 11.9% (22/185) SOFaaci-HEPES 48.8% (197/404) 43.1% (174/404) 11.7% (23/197) P-value 0.77 0.22 0.84

163 Treatment with gonadotrophin-releasing hormone at the time of AI in beef heifers that fail to express oestrus after an estradiol-based synchronisation protocol improves pregnancies per AI

2020 ◽  
Vol 32 (2) ◽  
pp. 208
Author(s):  
A. Butler ◽  
H. Butler ◽  
G. Cesaroni ◽  
R. Alberio ◽  
S. Perez Wallace ◽  
...  
Keyword(s):  
Pregnancy Loss ◽  
Fixed Time ◽  
P Value ◽  
Device Removal ◽  
Releasing Hormone ◽  
Condition Score ◽  
Gonadotrophin Releasing Hormone ◽  
To Receive ◽  
Angus Heifers ◽  
Intravaginal Device

Oestrus expression between progesterone (P4) withdrawal and fixed-time AI (FTAI) has been shown to improve pregnancies per AI (P/AI) by 27% in beef cattle. As a result, cattle that do not express oestrus after P4 withdrawal present a challenge to the efficiency of FTAI. The present study was designed to test the hypothesis that administration of gonadotrophin-releasing hormone (GnRH) at the time of AI in heifers that do not express oestrus can improve fertility. Two-year-old Angus heifers (n=1032) with a condition score of 2.75 to 3.5 at two locations in Argentina were used. On Day 0, heifers received an intravaginal device containing 0.5g of P4 (Cronipres, Biogenesis) and 2mg of oestradiol benzoate intramuscularly (Bioestrogen, Biogenesis). On Day 8, devices were removed and heifers received 150µg of d-cloprostenol intramuscularly (Enzaprost, Biogenesis), 0.5mg of oestradiol cipionate intramuscularly (Croni-Cip, Biogenesis), and an oestrus detection patch (Estrotect, Rockway Inc.). On Day 10, AI was performed in all heifers 50 to 54h after device removal. Heifers were categorised based on oestrus expression, and those that did not express oestrus were randomised to receive 100µg of gonadorelin acetate intramuscularly (Gonasyn, Syntex; n=158) concurrent with AI or remain as untreated controls (n=151). Pregnancy was determined using ultrasonography at Days 38 and 111 after AI. Differences in fertility were evaluated using generalised linear mixed models, and the results are shown in Table 1. Oestrus expression between device removal and FTAI was 70.1% (723/1032). Pregnancies per AI at Days 38 and 111 were different between groups (P<0.01). Heifers that expressed oestrus had greater P/AI than those that did not regardless of treatment (P<0.01). However, in heifers that did not express oestrus, treatment with GnRH at the time of AI resulted in greater P/AI than in control heifers (P=0.004). Similarly, P/AI at Day 111 were greater in heifers that expressed oestrus than in those that did not regardless of treatment (P<0.01). Heifers that did not express oestrus and were treated with GnRH had greater P/AI than those that did not express oestrus and remained as controls (P=0.02). Pregnancy loss between Days 38 and 111 was not different between groups; however, there was a tendency (P=0.06) for greater pregnancy loss in heifers that did not express oestrus and were treated with GnRH compared with heifers that expressed oestrus. In summary, treatment with GnRH at the time of AI is a suitable strategy to improve P/AI in heifers that fail to exhibit oestrus after an oestradiol-based synchronisation protocol. However, this strategy appears to increase pregnancy loss, and thus further research is needed to confirm this observation and the mechanisms underlying it. Table 1.Pregnancies per AI (P/AI) and pregnancy loss (%; no. in parentheses) in Angus heifers based on oestrus expression and treatment with GnRH Group P/AI Day 38 P/AI Day 111 Pregnancy loss Oestrus 68.9 (498/723)A 65.2 (471/723)A 5.4 (27/498) No oestrus control 29.8 (45/151)B 28.5 (43/151)B 4.4 (2/45) No oestrus + GnRH 45.6 (72/158)C 40.5 (64/158)C 11.1 (8/72) P-value <0.001 <0.001 0.15 A-CValues within a column with different superscripts differ significantly (P<0.05).

101 DOSE AND TIMING OF ADMINISTRATION OF PROSTAGLANDIN F2α DURING FIXED-TIME EMBRYO TRANSFER IN AN IN VITRO-PRODUCTION PROGRAM

2017 ◽  
Vol 29 (1) ◽  
pp. 158
Author(s):  
R. V. Sala ◽  
A. Garcia-Guerra ◽  
L. C. Carrenho-Sala ◽  
M. Fosado ◽  
E. Peralta ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Embryo Transfer ◽  
Pregnancy Loss ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
High Fertility ◽  
Full Dose ◽  
Half Dose ◽  
Utilisation Rate

Synchronization protocols for fixed-time embryo transfer (ET) contribute significantly to the overall cost of an in vitro-produced-ET program, primarily through the cost of drugs and the labour required. Optimization of synchronization protocols to reduce cost, while providing high fertility, have the potential to improve overall efficiency and profitability. The objective of the present study was to evaluate the effect of dose and schedule of administration of prostaglandin F2α (PGF) during a synchronization protocol for fixed-time ET. Holstein and cross-bred Holstein heifers (n = 3766) were synchronized using a modified 5-day CIDR Synch as follows: Day 0: CIDR inserted; Day 5: CIDR removed, PGF2α treatment; Day 8: gonadotropin-releasing hormone (GnRH; 100 μg of gonadorelin). On Day 5, at the time of CIDR removal, heifers were randomly assigned to a 2 × 2 factorial design to receive either a full or half dose of PGF (Cloprostenol; 500 v. 250 μg) and 1 (Day 5) or 2 (Day 6) administrations resulting in the following treatments: full dose Day 5 + Day 6 (n = 938); full dose Day 5 (n = 938); half dose Day 5 + Day 6 (n = 946); and half dose Day 5 (n = 944). Heifers were evaluated by ultrasonography 5 days after GnRH to determine presence and size of the corpus luteum. Heifers with a corpus luteum received a fresh in vitro-produced embryo 7 ± 1 days after GnRH administration, and pregnancy was determined by ultrasonography 32 and 60 days after GnRH. Fertility data were analysed by logistic regression and included the fixed effects of dose, time, and their interaction. Fertility results are shown in Table 1. Utilisation rate (transferred/treated) was not affected by dose (P = 0.66), time (P = 0.19), or their interaction (P = 0.17). The percentage of heifers detected in oestrus was not affected by dose (P = 0.13), time (P = 0.72), or their interaction (P = 0.89). There were no significant differences between doses of PGF (P = 0.32), time (P = 0.71), or their interaction (P = 0.80) on pregnancies per ET on Day 32. Similarly, no differences were found on pregnancies per ET on Day 60 between doses (P = 0.35), time (P = 0.96), or their interaction (P = 0.89). In addition, pregnancy loss between Day 32 and 60 was not affected by dose (P = 0.76), time (P = 0.66), or their interaction (P = 0.54). In conclusion, the use of a half dose of PGF once on Day 5 resulted in comparable utilisation rate and fertility as the observed with 2 full dose applications 24 h apart. As a result, the overall cost of the fixed-time ET program can be reduced by eliminating the need for a second PGF treatment and by decreasing the dose without compromising fertility. Table 1. Utilisation rate, oestrus expression, pregnancies per ET (P/ET), and pregnancy loss in recipients receiving either a full or half dose of prostaglandin F2α on Days (D) 5 and 6 or once on D 5

107 FACTORS THAT INFLUENCE FERTILITY IN AN IVF EMBRYO TRANSFER PROGRAM IN DAIRY HEIFERS

2016 ◽  
Vol 28 (2) ◽  
pp. 183 ◽  
Author(s):  
L. C. Carrenho-Sala ◽  
R. V. Sala ◽  
M. Fosado ◽  
D. C. Pereira ◽  
S. Garcia ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Pregnancy Loss ◽  
Embryo Quality ◽  
Prostaglandin F2α ◽  
Transfer Program ◽  
Dairy Heifers ◽  
Embryo Transfer Program ◽  
Embryo Stage ◽  
Major Factors

A retrospective study was performed to evaluate factors that influence pregnancy per embryo transfer (P/ET) in an IVF-embryo transfer program. A total of 5026 fresh in vitro-produced embryos were transferred during 2014 and evaluated for effects of embryo quality, embryo stage, size of corpus luteum (CL; 18–19.9 mm or ≥20 mm), interval from GnRH to embryo transfer, number of previous embryo transfer (0, 1, 2, 3, ≥4); and interaction of embryo stage and interval from GnRH to embryo transfer. One group (n = 850) had detection of oestrus after prostaglandin F2α application but most heifers (n = 4176) received fixed timed embryo transfer after a 5-day CIDR-Synch protocol: Day –8 CIDR inserted; Day –3 CIDR removed and prostaglandin F2α; Day –2 prostaglandin F2α; Day 0 GnRH. Ultrasound was performed on Day 6 after GnRH or oestrus to measure CL size and on Day 32 and 60 to determine pregnancy. Data for P/ET were analysed by logistic regression (LOGISTIC procedure, SAS 9.4). Embryo quality influenced P/ET at Day 32 [Grade 1 48.4% (1273/2631) v. Grade 2 37.6% (900/2395); P < 0.01] and at Day 60 [Grade 1 38.9% (1023/2631) v. Grade 2 29.0% (694/2395); P < 0.01], and altered pregnancy loss [Grade 1 19.6% (250/1273) v. Grade 2 22.9% (206/900); P = 0.03]. Stage of the embryo also had an effect on P/ET at Day 32 [Stage 6 35.5%a (582/1641), Stage 7 46.3%b (1431/3092), and Stage 8 54.6%c (160/293); P < 0.01] and at Day 60 [Stage 6 28.2%a (462/1641), Stage 7 36.6%b (1131/3092), and Stage 8 41.6%b (122/293); P < 0.01], but did not affect pregnancy loss (P = 0.22). Interestingly, interval from GnRH (or oestrus) until embryo transfer did not affect P/ET at Day 32 (P = 0.10), 60 (P = 0.23), or pregnancy loss (P = 0.3), nor was there an interaction between interval and embryo stage at Day 32 (P = 0.77), 60 (P = 0.96) or pregnancy loss (P = 0.55). As shown in Table 1, embryo stage 6 was always the lowest and stage 8 always the greatest P/ET regardless of interval from GnRH to embryo transfer. Size of CL also did not affect P/ET at Day 32 (P = 0.09), 60 (P = 0.21), or pregnancy loss (P = 0.90). Number of previous embryo transfer also did not alter P/ET at Day 32 [0 = 43.3% (886/2046), 1 = 44.1% (639/1450), 2 = 43.4% (444/1024), 3 = 42.6% (146/343), and ≥4 = 35.6% (58/163); P = 0.33] or 60 (P = 0.51) or pregnancy loss (P = 0.12). In conclusion, embryo stage and quality are the major factors that impacted P/ET in this study, with surprisingly little effect of interval from GnRH to embryo transfer, size of the CL, and number of previous embryo transfer. Thus, recipient programs for IVF-embryo transfer can be designed with substantial flexibility. Table 1.Effect of embryo stage and recipient synchrony on pregnancies per embryo transfer on Day 32 in recipient dairy heifers

90 Effect of the gonadotrophin-releasing hormone antagonist on the sheep follicular population

2021 ◽  
Vol 33 (2) ◽  
pp. 152
Author(s):  
H. C. Ferreira ◽  
G. B. Vergani ◽  
J. R. Bevilaqua ◽  
N. V. Rodrigues ◽  
M. E. F. Oliveira
Keyword(s):  
Gnrh Antagonist ◽  
Population Data ◽  
Average Diameter ◽  
Placebo Treatment ◽  
Releasing Hormone ◽  
Treatment Administration ◽  
Gonadotrophin Releasing Hormone ◽  
Post Hoc ◽  
Different Doses ◽  
Synchronization Protocol

The present study was designed to study the follicular population dynamics followed or not by treatment with different doses of the GnRH antagonist in sheep. A total of 18 ewes were submitted to short-term oestrus synchronization protocol (Oliveira et al. 2009 Proc. Braz. Congr. Anim. Reprod.). The animals were 2 or 3 years old, multiparous, and had a body score of 3 to 3.5. On Day 7 after ovulation of synchronized oestrus, females were randomly divided into groups (n=6/group) according to the dose of the gonadotrophin-releasing hormone (GnRH) antagonist (Firmagon®, Ferring Pharmaceuticals) subcutaneously administered: G-control: placebo treatment (administration of saline solution); G-lower dose: 215 µg/kg; and G-higher dose: 235 µg/kg of bodyweight. B-mode ultrasound exams of the ovaries were conducted daily from 1 day before treatment with GnRH antagonist until the females showed oestrous behaviour. Ultrasound equipment (MyLab Vet®, Esaote) was used coupled to a transrectal linear transducer with a frequency of 6 and 8MHz to assess the ovarian population. Data were compared between groups, evaluation days, and their interaction by ANOVA with post hoc using Tukey’s test (P&lt;0.05). There was no interaction (P&gt;0.05) between the studied effects (treatments and evaluation days). The number of small follicles (2–3.49mm) was higher (P=0.0002) in the G-lower dose (5.4±0.4) compared with the G-control (4.1±0.3) and G-higher dose (3.5±0.2). The number of large follicles (≥4.5mm) was lower (P=0.01) in the G-higher dose (0.2±0.0) compared with the G-control (0.5±0.1) and G-lower dose (0.4±0.1). The number of medium follicles (3.5– 4.49mm) and the average diameter of the follicles in the 3 categories of diameter did not differ (P&gt;0.05) between groups. The number of medium follicles differed (P=0.0131) between Days 8 and 15 after synchronized oestrus ovulation. The number of large follicles on Day 6 differed (P=0.0002) of Days 8, 9, 10, 11, 12, 16, and 17. The average diameter of medium follicles differed (P=0.0095) between Days 8 and 10. The number of small follicles and the average diameter of small and large follicles did not differ (P&gt;0.05) between days. In conclusion, the administration of the GnRH antagonist at a higher dose in sheep suppressed the development of large tertiary or antral follicles, whereas at a lower dose, it led to an increase in the population of small follicles.

scholarly journals 181COMPARISON OF THE PREGNANCY RATES AFTER SYNCHRONIZATION OF OVULATION USING GnRH AND PGF2± IN RECIPIENT DAIRY CATTLE

2004 ◽  
Vol 16 (2) ◽  
pp. 212 ◽  
Author(s):  
T. Nishisouzu ◽  
M. Sugawara ◽  
S. Aoki ◽  
K. Kishida ◽  
M. Moriyoshi ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Control Group ◽  
Corpora Lutea ◽  
Transfer Program ◽  
Chi Square ◽  
Follicle Diameter

Treatments with GnRH and PGF2α for synchronization of ovulation has resulted in acceptable pregnancy rates after fixed-time artificial insemination in dairy cows without estrus detection. The objective of the present study was to evaluate the practicability of ovulation synchronization (Ovsynch, Pursley JR et al. 1995 Theriogenology 44, 915–923) in dairy cattle using GnRH and PGF2α for the embryo transfer recipients. Dairy cattle (cows; n=100, heifers; n=88) were randomly allocated to one of two groups. The control group (cows; n=45, heifers; n=37) was composed of cows in natural estrus. The ovulation synchronization group (cows; n=55, heifers; n=51) was treated with an intramuscular injection of 100μg of GnRH at a random stage of the estrous cycle. Seven days later, the cattle received PGF2α (Cows; 25–30mg) or PGF2α analog (Heifers; 0.5mg) in order to regress the corpora lutea (CL). Forty-eight hours later, cows and heifers received a second injection of 100μg GnRH. Embryo transfer was carried out 7 days after the second injection of GnRH in the ovsynch group and 7 days after estrus in the control group. The cattle judged to have CL 17mm were classified as acceptable recipients. The size of the follicles and the CL were determined to be of estrus stage and embryo transfer by means of ultrasonography. The mean numbers of follicles and CL were analyzed by ANOVA, while pregnancy rates were analyzed by chi-square test. The results are presented in the Table. The proportion of cows and heifers determined to be acceptable embryo transfers was not different between the control group and the ovsynch group. There were no differences in the proportion of acceptable embryo transfers between the control group and the ovsynch group. Follicle diameter at the time of estrus in the control group (cows; 20.7±0.7mm, heifers; 16.8±0.5mm) were significantly larger than that of the ovsynch group (cows; 18.0±1.0mm, heifers; 14.7±0.2mm) (P&lt;0.05). Although CL diameter at the time of embryo transfer in heifers showed no differences between the control group and the ovsynch group (25.0±1.0mm v. 22.8±1.5mm), The CL diameter of the control cow group was larger than that of the ovsynch group (29.8±0.7mm v. 26.1±1.0mm, P&lt;0.05). However, no differences in pregnancy rate were seen between the control group and the ovsynch group. These results suggest that ovsynch can be effectively applied in an embryo transfer program for cattle. Table 1 Proportion of acceptable embryo transfer recipients and pregnancy rate in dairy cattle in the control ovsynch groups

scholarly journals Gestational losses after innovating with two embryos in a fixed-time embryo transfer program

2021 ◽  
Vol 14 (10) ◽  
Author(s):  
Carla Neves Barbosa ◽  
Felipe De Col ◽  
Juan Carlos Domínguez Fernández de Tejerina ◽  
Rodolfo Cassimiro de Araujo Berber
Keyword(s):  
Embryo Transfer ◽  
Birth Rate ◽  
Considerable Increase ◽  
Hormonal Treatment ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Corpora Lutea ◽  
Transfer Program ◽  
Embryo Transfer Program ◽  
Group 1

The aim of this study was to quantify the pregnancy rate after implantation of two embryos after FTET protocols, as well as to monitor pregnancy losses until parturition, evaluating, mainly, if this strategy results in more number of animals born. Therefore, 423 multiparous recipients were selected, standardized in terms of body score, who had high-quality corpora lutea. Animals were randomly divided into two groups according to one or two embryos transferred (1 embryo = Control, n = 237; 2 embryos = Group 1, n = 186). All recipients received the same hormonal treatment, which consisted of administering, on Day 0, 2 mL of estradiol benzoate (Gonadiol, ZOETIS) + 1.9 g multidose 1st use progesterone implant (CIDR, ZOETIS); on Day 8 the implants were removed + injected 0.4 mL of estradiol cypionate (E.C.P, ZOETIS) + 1.5 mL of eCG (Novormon, ZOETIS) + 1 mL of dinoprost tromethamine (Lutalyse, ZOETIS). The animals were evaluated by ultrasonography at 30 and 60 days after embryo transfer, to diagnose the success rate and embryo losses during this period. Furthermore, information was collected on births, length of gestation, number of twin births, number of childbirth assistance and the weight of the calves. The results showed that Group 1 had better success than the Control, with higher conception rates at 30 days (68.3% vs. 53.2%, P<0.001) and at 60 days (62.9% vs. 52.3%; P<0 .05). The number of animals born was also higher for Group 1 (53.3% vs. 43.3%, P<0.01). The percentage of twins born in Group 1 was 17.9%, and the animals had lower weight compared to the Control (34.29 + 7.36 vs 37.63 + 5.73, P<0.05). The length of pregnancy and the number of assistances were similar between groups. In conclusion, the strategy adopted in this experiment suggests a considerable increase in the calf birth rate, but losses during pregnancy and their mechanisms need to be elucidated.

160 Increasing gonadotrophin-releasing hormone dose at initiation of a 5-day CO-Synch protocol increases ovulatory response but not fertility in yearling beef heifers

2020 ◽  
Vol 32 (2) ◽  
pp. 206
Author(s):  
E. Rojas Canadas ◽  
S. E. Battista ◽  
J. Kieffer ◽  
S. Wellert ◽  
A. Garcia Guerra
Keyword(s):  
Dose Group ◽  
Fixed Time ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Double Dose ◽  
Device Removal ◽  
Beef Heifers ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone ◽  
To Receive

Heifers typically have a reduced ovulation rate following gonadotrophin-releasing hormone (GnRH) application at initiation of a CO-Synch + controlled internal drug release (CIDR) protocol. Thus, the objective of the present study was to determine whether increasing the dose of GnRH at initiation of a 5-day CO-Synch protocol in beef heifers would improve ovulation rate and therefore increase pregnancies per AI (P/AI). Angus yearling heifers (n=299) at five locations in Ohio (United States) were randomised to receive either 100µg (single; n=149) or 200µg (double; n=150) of gonadorelin acetate (Gonabreed, Parnell) at initiation of a 5-day CO-Synch. On Day −8, heifers received a new intravaginal progesterone-releasing device (1.38g of progesterone; CIDR, Zoetis) and either a single or double dose of GnRH as described above. Five days later (Day −3), devices were removed, 1000µg of cloprostenol sodium (Estroplan, Parnell) was administered, and an oestrous detection patch was applied (Estrotect, Rockway Inc.). Sixty hours after device removal, AI was performed concurrently with the administration of 100µg of GnRH. Pregnancy was determined using ultrasonography 35 days after AI. Ovaries from a subset of animals (n=178) were examined on Days −8 and −3 using ultrasonography to determine the presence of corpora lutea (CL) and the size of the largest follicle. Data were analysed using the GLIMMIX procedure of SAS ver. 9.4 (SAS Institute Inc.). Oestrous expression was similar (P=0.50) between heifers treated with a single (49.0%) or double (52.7%) dose of GnRH. Overall, P/AI was similar (P=0.35) between heifers receiving a single (43.6%; 65/149) or double (38.7%; 58/150) dose of GnRH at initiation of the protocol. However, increasing the dose of GnRH resulted in a greater (P=0.04) ovulation rate in heifers in the double-dose group (40.9%; 36/88) compared with those in the single-dose group (26.1%; 23/88). In addition, heifers with a CL at the time of treatment had reduced ovulatory response to GnRH treatment (16.0%) compared with heifers without a CL (53.7%; P=0.001); however, there was no treatment×CL presence interaction (P=0.69). Heifers that did not ovulate to the initial GnRH treatment had a greater (P=0.0008) diameter of the largest follicle on Day −3 compared with heifers that did ovulate (11.4±0.2 vs. 10.0±0.3). Furthermore, heifers that did ovulate after the initial GnRH had greater (P=0.04) P/AI (52.5%) than heifers that did not ovulate (40.2%), and heifers with a CL on Day −8 tended (P=0.07) to have greater P/AI (47.9%) than heifers without a CL (40.2%). In addition, heifers with a CL present on Day −3 had greater (P=0.04) P/AI (48.2%) than heifers without a CL (31.7%). In summary, increasing the dose of GnRH at initiation of a 5-day CO-Synch did not affect fertility to fixed-time AI but enhanced ovulation rate in beef heifers. Furthermore, heifers that did ovulate at initiation of the protocol or that had a CL at device insertion or removal had greater fertility to fixed-time AI. Thus, alternative strategies that maximise ovulation at initiation of the synchronisation protocol are needed.

104 FACTORS AFFECTING PREGNANCY RATES AND EMBRYO/FETAL LOSSES IN RECIPIENTS RECEIVING IN VITRO-PRODUCED EMBRYOS BY FIXED-TIME EMBRYO TRANSFER

2017 ◽  
Vol 29 (1) ◽  
pp. 160
Author(s):  
A. Tribulo ◽  
A. Cedeño ◽  
B. Bernal ◽  
S. Andrada ◽  
J. L. Barajas ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Device Removal ◽  
Releasing Hormone ◽  
Condition Score

A retrospective analysis evaluated pregnancy rates and embryo losses with in vitro-produced embryos in a commercial embryo transfer program on 15 different beef farms. Recipients were beef cows and heifers (n = 1841) that were synchronized with 5 different protocols and transferred at a fixed-time (FTET). Recipients were examined by ultrasonography on Day 0, and those with a corpus luteum (CL) or a follicle ≥8 mm in diameter and with body condition score 2 to 4 (1 to 5 scale) were synchronized. The synchronization treatments were as follows. (T1) Recipients received an intravaginal device with 0.5 g of progesterone plus 2 mg of oestradiol benzoate on Day 0; device removal, plus 500 μg of cloprostenol (prostaglandin F2α), 400 IU of eCG, and 0.5 mg of oestradiol cypionate on Day 8; and FTET on Day 17. (T2) This treatment was similar to T1 but 1 mg of oestradiol cypionate was injected at device removal instead of 0.5 mg of oestradiol cypionate. (T3) This treatment was similar to T1 except that animals were tail-painted on Day 8 and observed on Day 10. Those with the tail-paint intact on Day 10 received 100 μg of gonadorelin (gonadotropin-releasing hormone) and all recipients were FTET on Day 17. (T4) Recipients received a progesterone device on Day 0; device removal, prostaglandin F2α, and eCG on Day 5; gonadotropin-releasing hormone on Day 8; and FTET on Day 15. (T5) Recipients received a progesterone device and 2 mg of oestradiol benzoate on Day 0; device removal, prostaglandin F2α, and eCG on Day 6; gonadotropin-releasing hormone on Day 9; and FTET on Day 16. On the day of FTET all recipients with CL ≥18 mm in diameter (G1), ≥16 and <18 mm in diameter (G2), and ≥14 mm and <16 mm in diameter (G3) received in vitro-produced fresh embryos. Pregnancy was diagnosed by ultrasonography at 30 and 60 days of gestation, and data were analysed by logistic regression. The overall proportion of recipients synchronized that were FTET was 80.8% (1487/1841), with a 30-day pregnancy rate to FTET (P/FTET) of 45.6% (678/1487) and the rate of 30- to 60-day embryo/fetal loses on the 528 recipients that were re-checked at 60 days was 12.8% (68/528). There were no significant differences in P/FTET among operators, animal category, time of the year, embryo stage, or body condition score; however, there was a significant effect of farm (P < 0.001) and CL diameter (P < 0.05), but no interaction between CL diameter and farm or treatment (P > 0.1). Recipients with G1 (443/953, 46%) and G2 (221/462, 47%) CL had higher pregnancy rates than those with G3 CL (23/71, 32%). There was a significant effect of synchronization treatment on the proportion of recipients transferred and on P/FTET (P < 0.01) that was highly influenced by farm (farm by treatment interaction P < 0.01). The proportions of recipients selected for embryo transfer were as follows: T1: 386/486, 79.4%; T2: 233/331, 70.3%; T3: 342/377, 90.7%; T4: 126/160, 78.7%; and T5: 400/487, 82.1%. The P/FTET were as follows: T1: 190/386, 49.2%; T2: 96/233, 41.2%; T3: 175/342, 51.1%; T4: 49/126, 38.8%; and T5: 168/400, 42.0%. Although 30- to 60-day embryo/fetal losses were not influenced by synchronization treatments, they were highly influenced by farm (P < 0.001) and ranged from 0 to 34.5%. In conclusion, P/FTET in a commercial program with beef in vitro-produced embryos was influenced by factors related to the recipient (CL diameter) and the environment (farm), whereas embryo/fetal losses were influenced by farm but not treatment or recipient factors.

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