Do high progesterone concentrations decrease pregnancy rates in embryo recipients synchronized with PGF2α and eCG?

Nogueira, Marcelo Fábio Gouveia; Melo, D. S.; Carvalho, Luciano Mundim de; Fuck, Egon José; Trinca, Luzia A.; Barros, C. M.

doi:10.1016/j.theriogenology.2003.07.012

Cited by 42 publications

(28 citation statements)

References 32 publications

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“…Accordingly, bovine embryo recipients with HCP 4 showed a decline in pregnancy rate at both 21 and 83 days after embryo transfer (Nogueira et al 2004). Although bovine embryos recovered from superovulated recipients with HCP 4 displayed an increased size on day 13 (Lonergan et al 2007), studies in cattle has shown that HCP 4 can reduce the rate of in vitro embryo formation (Pereira et al 2009) and decrease in vivo embryo survival (Stronge et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Efficiency of two timed artificial insemination protocols in Murrah buffaloes managed under a semi-intensive system in the tropics

Oropeza

Rojas

Velazquez

et al. 2010

Trop Anim Health Prod

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The objective of the study was to determine the efficiency of ovsynch (OV) versus presynch-ovsynch (P-OV) protocol for synchronization of ovulation and timed artificial insemination (TAI) in female buffaloes. The OV group (n = 40) received gonadotrophin-releasing hormone (GnRH) on day 0 (random day of the estrous cycle), prostaglandin PGF₂α on day 7 and a second GnRH administration on day 9 followed by a single artificial insemination (AI) 16-20 h later. The P-OV group (n = 40) received two PGF₂α injections 14 days apart, with the second injection administered 14 days before starting the OV protocol. Progesterone (P(4)) was measured at the time of PGF₂α administration (within the OV protocol) and AI. Neither ovulation rate ((24 h after TAI) OV 90%-36/40 vs. P-OV 85%-34/40) nor pregnancy rates ((day 60 after TAI) OV 35%-14/40 vs. P-OV 45%-18/40) differed between the two protocols. Pregnant buffaloes had lower concentrations of P(4) at AI compared with non-pregnant animals in the OV group (0.7 +/- 0.1 vs. 1.1 +/- 0.1 ng/ml); but in the P-OV group, differences did not reach statistical significance (0.8 +/- 0.1 vs. 1.0 +/- 0.1 ng/ml). This apparent trend reached statistical significance when the analysis was carried out in animals from both protocols (0.7 +/- 0.1 (pregnant) vs. 1.1 +/- 0.1 (non-pregnant) ng/ml). In conclusion, both protocols synchronize ovulation effectively with no significant differences in conception rates. High concentrations of P(4) at AI seem to be detrimental for the establishment of pregnancy in lactating buffalo cows.

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Section: Discussionmentioning

confidence: 99%

Efficiency of two timed artificial insemination protocols in Murrah buffaloes managed under a semi-intensive system in the tropics

Oropeza

Rojas

Velazquez

et al. 2010

Trop Anim Health Prod

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“…Baruselli et al (2001) found increase in the concentration of P4 in accordance with the corpus luteum increase in crossbred recipients and according to Binelli et al (2001), larger corpus luteum in recipients may increase pregnancy rates in embryo transfer programs. However, Nogueira et al (2004) found an opposite result, in which recipients that received doses of 400 and 600 IU of equine chorionic gonadotrophin showed higher concentrations of P4 and higher corpus luteum, but lower pregnancy rates than those not treated or given 200 IU of equine chorionic gonadotrophin.…”

Section: Introductionmentioning

confidence: 94%

Effect of breed and corpus luteum on pregnancy rate of bovine embryo recipients

et al. 2012

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-The objective of this study was to evaluate pregnancy rates of recipients of different breed groups (Nellore and crossbreed), as well as the effects of size and type of the corpus luteum (CL) on plasmatic concentrations of progesterone and pregnancy rates of embryo recipients. A total of 152 heifers were synchronized with progesterone implants and on the day of embryo transfer, previously obtained by superovulation and frozen in ethylene glycol, the diameter and type of the corpus luteum (cavitary and compact) was measured and blood was collected for progesterone measurement. The pregnancy rate was 44.1%, with a diameter of corpus luteum higher in recipients that became pregnant (2.03±0.41) compared with nonpregnant ones (1.86±0.34 cm). Plasmatic concentrations of progesterone did not differ between pregnant (1.50±1.05) and non-pregnant (1.31±0.91 ng/mL) animals. The type of corpus luteum did not influence the pregnancy rates. Only Angus and crossbred Marchigiana differ among themselves in pregnancy rates (33.3 and 59.2%, respectively). The pregnancy probability was affected only by CL diameter, but not by P4 plasmatic concentration. Selection of the corpus luteum size at the time of embryo transfer is an important factor to increase pregnancy rates in recipients, and compact and cavitary corpora lutea do not influence the pregnancy rates of bovine embryo recipients. Nellore recipients have pregnancy rates that are satisfactory and comparable to crossbred (Bos taurus × Bos indicus) recipients.

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“…In the present study, the eCG treatment aimed to provide enough physiological support for follicle and oocyte development and to avoid superovulation and its deleterious effects on fertility (Nogueira et al, 2004). The relatively low eCG dosage also aimed to limit possible antieCG antibody production as well as to provide a cheaper and less labor-intensive option compared with regular FSH-protocols.…”

Section: Resultsmentioning

confidence: 98%

“…Some authors suggested that FSH-like effects synchronize the follicular development by accelerating growth and in vivo oocyte maturation, which could benefit later embryo development in vitro (Gibbons et al, 1994). Furthermore, the use of eCG may have altered the follicular environment around the oocytes, influencing their quality undetectably under the present experimental scope (Roth et al, 2002;Nogueira et al, 2004). It is well described that follicle stimulating hormone, as well as exogenous rbST, increase IGF-I receptor density (Spicer et al, 1994;Cushman et al, 2001) and decrease the amount of IGF 2-binding proteins in bovine follicles (Echternkamp et al, 1994).…”

Section: Resultsmentioning

confidence: 98%

Association of recombinant bovine somatotropin (rBST) with equine chorionic gonadotropin (eCG) on antral follicle count and oocyte production in Holstein and Tabapuã heifers

et al. 2012

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-The objective of this study was to investigate whether the use of rbST and eCG prior to ultrasound-guided follicular aspiration (OPU) improves oocyte yield and quality in Tabapuã and Holstein heifers. The study was conducted in two phases, 20 days apart, in a change-over design. The dominant follicle was ablated two days (D-2) before two treatments: stimulation (6 Holstein and 8 Tabapuã), 500 mg of rbST (Boostin ® ) on D0 and 500 IU of eCG (Folligon) on D2; and control (6 Holstein and 8 Tabapuã), in which heifers received injections of the excipient. Heifers were aspirated on D4. Oocytes were subjected to a well established commercial in vitro embryo production protocol (Vitrogen ® ) and embryos were evaluated seven days after fertilization. There was an effect from the interaction of treatment and breed, so that hormonal stimulation increased antral follicle count (2-8 mm) in Tabapuã (29.9±2.6 to 41.4±2.6), but not in Holstein heifers (14.4±2.6 to 15.5±2.6). Tabapuã heifers had higher mean antral follicle count than Holsteins (35.6±1.8 vs. 15.0±2.1). The number of viable oocytes was not increased by stimulation in Tabapuã (from 4.7±1.0 to 5.2±1.1 in control and simulation, respectively) or in Holstein heifers (1.3±1.9 to 2.0±1.6 in control and simulation, respectively). There was no difference in the percentage of heifers with more than five viable oocytes in the group treated (33 vs 27%). The number of blastocysts was not affected by treatment (1.75 vs. 1.00 in hormonal stimulation and control, respectively). The increase in antral follicle count in the stimulated Tabapuã heifers did not reflect upon oocyte yield. The differential breed response to the hormonal treatment underscores the need for additional tests, especially for the Holstein breed, in order to enhance OPU efficiency.

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Do high progesterone concentrations decrease pregnancy rates in embryo recipients synchronized with PGF2α and eCG?

Cited by 42 publications

References 32 publications

Efficiency of two timed artificial insemination protocols in Murrah buffaloes managed under a semi-intensive system in the tropics

Efficiency of two timed artificial insemination protocols in Murrah buffaloes managed under a semi-intensive system in the tropics

Effect of breed and corpus luteum on pregnancy rate of bovine embryo recipients

Association of recombinant bovine somatotropin (rBST) with equine chorionic gonadotropin (eCG) on antral follicle count and oocyte production in Holstein and Tabapuã heifers

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