Characterization of the uterine environment during early conceptus expansion in the bovine

Geisert, R. D.; Zavy, M. T.; Biggers, B. G.; Garrett, Joy; Wettemann, R. P.

doi:10.1016/0378-4320(88)90003-6

Cited by 45 publications

(15 citation statements)

References 28 publications

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“…However, maintenance of pregnancy during the gestation period could possibly be influenced by the size and the number of TVs at time of transfer. Considering that the length of the conceptus on Day 15 is about 16 mm (range 5-20 mm) in pregnant cows [31], the amount of maternal recognition signal might increase according to size of TVs. In another study, the progesterone concentration was investigated for its influence on the development of conceptus and production of IFN-τ.…”

Section: Discussionmentioning

confidence: 99%

Transition of the Pregnancy Rate of Bisected Bovine Embryos after Co-transfer with Trophoblastic Vesicles Prepared from In Vivo-cultured In Vitro-fertilized Embryos

2005

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Abstract. Bisected bovine embryos were co-transferred with trophoblastic vesicles (TVs). These TVs were prepared by dissection of conceptuses that were collected by uterine flushing after culture for seven days in the uterus following transfer of embryos derived by in vitro fertilization (IVF). Pregnancy diagnoses were performed twice, between Day 26 and Day 43 and between Day 38 and Day 73 post-estrus by ultrasonography. The pregnancy rate was significantly increased at first pregnancy diagnosis when demi-embryos were transferred with TVs (66.7%, 16/24) compared with the control group (34.5%, 10/29) (P<0.05). Three losses occurred in the co-transfer group between the first and second pregnancy diagnosis. The final pregnancy rates according to delivered offspring were 41.7% (10/24) and 27.6% (8/29), respectively. There were no statistically significant differences between the pregnant and non-pregnant groups with regard to the average diameter of the TVs measured before transfer at three points during the gestation period. The birth weight and gestation lengths of the offspring were almost the same for the co-transfer and control groups. In the co-transfer group, the genetic identities of calves from the separated embryos were not affected by the TVs, as confirmed by parental blood type testing. Delivered offspring in co-transferred groups showed normal morphology. In conclusion, the present study indicates that co-transfer of TVs prepared from conceptuses cultured in vivo following transfer of IVF embryos enhances the fertility of demi-embryos during the early stages of pregnancy, as has similarly been shown in previous research for those prepared from in vivo embryos.

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Section: Discussionmentioning

confidence: 99%

Transition of the Pregnancy Rate of Bisected Bovine Embryos after Co-transfer with Trophoblastic Vesicles Prepared from In Vivo-cultured In Vitro-fertilized Embryos

2005

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“…The observation that IFN-t secretion by blastocyst outgrowths can be sustained well beyond when its production would have ceased in vivo (Stojkovicr et al, 1995) seems to suggest the necessity for maternal factors for IFN-t downregulation. Moreover, it has been well established that uterine secretions are essential for conceptus development Geisert et al, 1988;Roberts and Bazer, 1988;Simmen and Simmen, 1991) and that chemical ablation of uterine secretions prevents establishment and maintenance of pregnancy (Gray et al, 2000). The third experiment in the present study was, therefore, designed to examine the possibility that factors present in the uteri of sheep could affect the development and IFN-t secretion of bovine blastocysts during in vitro culture.…”

Section: Introductionmentioning

confidence: 99%

Control of interferon-? secretion by in vitro-derived bovine blastocysts during extended culture and outgrowth formation

2001

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A series of experiments was conducted to examine the pattern of interferon‐τ (IFN‐τ) secretion by bovine blastocysts during extended culture in vitro. In the first experiment, blastocysts were cultured individually for three 48‐hour periods. The day of blastocyst formation affected how much IFN‐τ was produced during the first two culture periods, but not during the third period. The overall secretion of IFN‐τ during the 6‐day period increased significantly and well beyond what could be accounted for by the concomitant increase in cell numbers. In the second experiment, blastocysts were initially cultured in individual droplets for 48 hr, then plated into 48‐well plates. Medium concentrations of IFN‐τ were determined after 48 hr and again after 6 and 12 days of culture. Initial IFN‐τ secretion did not affect the ability to form outgrowths or their final size, and initial differences in secretion between groups of blastocysts had disappeared by the second and third analyses. In the third experiment, blastocysts were cultured individually for 48 hr in droplets containing the medium that had been flushed through the uteri of non‐pregnant sheep on days 10, 12, and 15 of the estrous cycle. Culture in the medium obtained from the Day 15 flush significantly increased the number of cells that blastocysts contained, as well as IFN‐τ secretion. Mol. Reprod. Dev. 58:390–397, 2001. © 2001 Wiley‐Liss, Inc.

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“…Portanto, a despeito da potência luteolítica do 17 b -estradiol 5,17 , é cabível inferir que a ação luteotrófica da hCG 8,11 proveu determinadas condições uterinas 7 que favoreceram o desenvolvimento otimizado Tabela 2 -Taxas de prenhez (TP) 1 à inseminação artificial (IA) em tempo fixo ( IATF ) e TP acumuladas ao final da estação (TP acum ). São Carlos, 2004 do concepto e amplificaram a produção de moléculas sinalizadoras da sua presença 9 , prevenindo assim o desencadeamento da luteólise mesmo após indução pelo estrógeno. Corroborando esta inferência, verifica-se que nem sempre vacas Bos indicus com presença de corpo lúteo respondem aos agentes luteolíticos exógenos.…”

Section: Discussionunclassified

“…7 Por outro lado, a suplementação com progesterona aumenta a taxa de crescimento embrionário e também a capacidade em produzir a molécula sinalizadora da sua presença no útero (interferon-t). 9 Uma estratégia para aumentar a progesterona plasmática consiste na aplicação de hCG entre os dias 4 e 7 do ciclo estral para induzir a formação de um corpo lúteo acessório. 10,11,12 Com efeito, numa revisão de 17 estudos individuais verificou-se que, vacas suplementadas com progesterona após a inseminação artificial obtiveram taxas de concepção aproximadamente 5% mais altas do que vacas não suplementadas.…”

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Taxas de serviço, concepção e prenhez de vacas nelore tratadas com gonadotrofina coriônica humana e 17²-estradiol após a inseminação artificial em tempo fixo

Machado

Bergamaschi

Barbosa

et al. 2008

Braz. J. Vet. Res. Anim. Sci.

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Avaliaram-se estratégias para reduzir a mortalidade embrionária em bovinos. Vacas Nelore (Bos taurus indicus) foram inseminadas em tempo fixo (IATF - D0) após o protocolo GnRH/PGF2±/GnRH e divididas nos grupos: Controle (Gc; n=55), hCG (GhCG; n=55) recebeu 3000 UI da hCG no D5 , E2 (G E2; n=55) recebeu 5 mg de 17²-Estradiol (E2) no D12 e hCG/E2 (GhCG/E2; n=55) recebeu 3000 UI da hCG no D5 e 5 mg do E2 no D12. A IA TF foi o 1º dia da estação de reprodução de 64 dias. Usou-se o teste do Ç2 para comparar as taxas de serviço (TS), concepção (TC) e prenhez à IA TF (TP IATF), às IAs de repasse e acumuladas. A TS e a TC das IAs de repasse não diferiu (P>;0,10). Houve diferenças nas TP IATF (P<0,05), pois a TP IATF do G E2 (5,4%) foi a mais baixa e a do Gc (34,5%) e GhCG (36,5%) tenderam (P<0,10) ser maiores que a do GhCG/E2 (18,2%). Não houve efeito da hCG sobre as taxas de prenhez. O E2 reduziu a TP IATF e ao final da estação as vacas que receberam o E2 (G E2 + GhCG/E2) tiveram TPacum (66,4%) mais baixa (P<0,05) de que aquelas (80,9%) que não receberam (G C + GhCG). Em conclusão, as estratégias adotadas de manipulação luteínica ou folicular não aumentaram as taxas de prenhez em vacas Nelore após uma IA TF.

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Characterization of the uterine environment during early conceptus expansion in the bovine

Cited by 45 publications

References 28 publications

Transition of the Pregnancy Rate of Bisected Bovine Embryos after Co-transfer with Trophoblastic Vesicles Prepared from In Vivo-cultured In Vitro-fertilized Embryos

Transition of the Pregnancy Rate of Bisected Bovine Embryos after Co-transfer with Trophoblastic Vesicles Prepared from In Vivo-cultured In Vitro-fertilized Embryos

Control of interferon-? secretion by in vitro-derived bovine blastocysts during extended culture and outgrowth formation

Taxas de serviço, concepção e prenhez de vacas nelore tratadas com gonadotrofina coriônica humana e 17²-estradiol após a inseminação artificial em tempo fixo

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