Early embryonic death in mares: clinical and hormonal aspects

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ultrasonographic evaluation of the conceptus from days 10 to 60 of pregnancy in jennies

Daily ultrasound examinations were conducted from Days 10 to 60 (ovulation = Day 0) of pregnancy to monitor the conceptus in jennies (n = 12). The embryonic vesicle was first detected on Day 11.5 +/- 0.9 (mean +/- SD; range 10 to 13d) and was mobile until movement ceased (fixation) on Day 15.5 +/- 1.4 (range, 13 to 18d). The vesicle was spherical from Days 10 to 18 (mean growth rate, 3.2 mm/d), non spherical (irregular) with a reduced growth rate (0.5 mm/d) from Days 19 to 29, and then grew at a moderate rate (1.6 mm/d) up to Day 46. on average, detection of the embryo proper (consistently located on the ventral aspect of the yolk sac) and embryonic heartbeat were Days 20.7 +/- 1.2 and 23.5 +/- 1.3, respectively. Formation of the allantoic sac was first detected on Day 24.4 +/- 1.7 and was complete on Day 36.8 +/- 1.6. Descent of the fetus (and formation of the umbilical cord) began on Day 37.9 +/- 1.7 and was complete on Day 44.1 +/- 2.1. Crown-ramp length averaged 3.7, 15.4, 22.7, 37.5 and 59.6 mm on Days 20, 30, 40, 50 and 60, respectively. In general, morphologic features and dates of occurrence were similar to those reported previously in the mare. (C) 1998 by Elsevier B.V.

Concentração de progesterona e de estradiol 17-beta e características ultra-sonográficas da vesícula embrionária no início da gestação em éguas Puro Sangue Inglês

Associaram-se dosagens séricas de progesterona e estradiol 17-beta, realizadas durante os primeiros 36 dias de prenhez em 30 éguas PSI, com exames ultra-sonográficos, para verificar fenômenos que ocorrem com a vesícula embrionária. As éguas foram divididas em dois grupos de 15 animais, o primeiro constituído por éguas paridas e o segundo por éguas virgens ou vazias na estação anterior. Por meio da ultra-sonografia foram verificados fenômenos de mobilidade, fixação e orientação da vesícula embrionária. As concentrações séricas de progesterona e estradiol 17-B variaram (P<0,01) durante o período estudado porém não foi possível estabelecer uma correlação entre concentrações desses hormônios com desenvolvimento da vesícula embrionária. A concentração de estradiol 17-betacirculante foi maior (P<0,01) nas éguas paridas.

Description and genetic analysis of three sets of monozygotic twins resulting from transfers of single embryos to recipient mares

Case Description-3 sets of monozygotic twins resulting from transfers of single embryos to recipient mares were examined. Clinical Findings-In all 3 recipient mares with twin pregnancies, only 1 embryonic vesicle was detected before day 25 of gestation. In 1 recipient mare, 2 apparent adjacent vesicles, each containing an embryo with a heartbeat, were visualized on ultrasonographic examination on day 37 of gestation. The other 2 recipient mares underwent ultrasonographic examination on day 30 of gestation, at which time only 1 vesicle and embryo was identified. In these latter 2 recipient mares, however, a thorough ultrasonographic examination for a second conceptus on day 30 had not been performed, as only 1 embryo had been transferred and visualized on early ultrasonographic examination. Treatment and Outcome-All twin pregnancies resulted in death of both fetuses. Genetic analysis confirmed that each set of monozygotic twins originated from the transferred embryo. Clinical Relevance-Monozygotic twin pregnancy may occur after embryo transfer; thus recipient mares should be examined thoroughly for multiple conceptuses, especially between 25 and 30 days of gestation. At this time, the allantoides of monozygotic twins should be visible ultrasonographically and effective management may still be possible.

Efeitos da aplicação do benzoato de estadiol na prevvenção de gestação em cadelas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência das alterações degenerativas endometriais e da idade hemodinâmica do trato reprodutivo de éguas após a inseminação artificial e durante as fases iniciais do desenvolvimento embrionário

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Developmental aspects of early pregnancy in mares

In mares, the embryo migrates to the uterus between days 5 and 6 postovulation beginning its mobility through all uterine segments, which is essential for the maternal recognition of pregnancy. During the mobility phase, the embryonic vesicle shows a linear growth rate until its fixation between days 15 and 17, when the orientation phenomenon occurs. From fixation to day 28 of pregnancy, the embryonic growth is less evident (plateau) by cross-section ultrasound examination. After this period the linear growth rate is reestablished until day 46. This plateau is attributed to the increased uterine tone that compresses the vesicle and to volume expansion, making it difficult to detect the conceptus growth only by the cross-section diameter. Around day 20, the embryo proper is visualized as an echogenic spot in the ventral aspect of the vesicle. Additionally, development of allantoic sac, embryonic heartbeat, yolk sac regression and posterior umbilical cord formation also can be visualized from days 20 to 40. An intimate interaction between uterus and conceptus is essential for the normal pregnancy development. Color-and spectral-Doppler ultrasonography can be useful for the evaluation of this interface. A gradual increase on uterine vascularity during the early pregnancy and transient changes in endometrial vascularity accompanying the vesicle location during the mobility phase have been described. Around day 38 of gestation, the formation of the endometrial cups begins and, consequently, the synthesis of the equine chorionic gonadotropin (eCG) induces the formation and development of supplementary corpora lutea, which are important to secrete progesterone and to maintain pregnancy until around day 120.

Utiização de altrenogest injetável par o estabelecimento e manutençao da gestação em éguas receptoras de embriões acíclicas

Pós-graduação em Medicina Veterinária - FMVZ

Ultrasonography of the conceptus development from days 15 to 60 of pregnancy in non-cyclic recipient mares

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural and ultrastructural analysis of embryonic development of Prochilodus lineatus (Valenciennes, 1836) (Characiforme ; Prochilodontidae)

This survey was performed to characterize the embryogenesis of Prochilodus lineatus. Seven stages of embryo development were identified - zygote, cleavage, blastula, gastrula, segmentation, larval and hatching - after a period of incubation of 22h (24 degrees C) or 14h (28 degrees C). The following cleavage pattern was identified: the first plane was vertical (2 blastomeres); the second was vertical and perpendicular to the first (4 blastorneres); the third was vertical and parallel to the first (4 x 2); the fourth cleavage was vertical and parallel to the second (4 x 4); the fifth was vertical and parallel to the first (4 x 8); and the sixth cleavage was horizontal (64 blastomeres). At the blastula stage (3.0-4.0 h (24 degrees C); 1.66-2.0h (28 degrees C) irregular spaces were detected and periblast structuring was initiated. At the gastrula stage (4.0-8.0 h (24 degrees C); 3.0-6.0 h (28 degrees C) the epiboly, convergence and cell movements, as well as the formation of embryonic layers, had begun. The segmentation stage (10.0-15.0h (24 degrees C); 7.0-10.0h (28 degrees C)) was characterized by a rudimentary formation of organs and systems (somites, optic vesicle and intestinal delimitation). The embryo at the larval stage (16.0-21.0 h (24 degrees C); 11.0-13.0 h (28 degrees C)) showed a free tail, more than 25 somites, an optic vesicle and a ready-to-hatch larval shape. The blastomeres at cleavage stage had disorganized nuclei indicating high mitotic activity. At gastrula, the blastomeres and the periblast had euchromatic nuclei and a large number of mitochondria and vesicles. The yolk was organized into globose sacs, which were dispersed into small pieces prior to absorption.

Structural and ultrastructural characterization of the embryonic development of Pseudoplatystoma spp. hybrids

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A chimeric vitronectin : IGF-I protein supports feeder-cell-free and serum-free culture of human embryonic stem cells

This paper was retracted by the Journal of Stem Cells and Development on February 15, 2013.