Morpho-physical Recording of Bovine Conceptus (Bos indicus) and Placenta from Days 20 to 70 of Pregnancy

Abstract

The study is based on 141 pregnant Bos indicus cows, from days 20 to 70 post-insemination. First, special attention was given to the macroscopically observable phenomena of attachment of the conceptus to the uterus, i.e. the implantation, from about days 20 to 30 post-insemination up to day 70, and placentome development by growth, vascularization and increase in the number of cotyledons opposite to the endometrial caruncles. Secondly, as for the conceptuses, semiquantitative, statistical analyses were performed of the lengths of chorio-allantois, amnion and yolk sac; and the different parts of the centre and two extremes of the yolk sacs were also analysed. Thirdly, the embryos/foetuses corresponding to their membranes were measured by their greatest length and by weight, and described by the appearance of external developmental phenomena during the investigated period like neurulation, somites, branchial arcs, brain vesicles, limb buds, C-form, pigmented eye and facial grooves. In conclusion, all the data collected in this study from days 20 to 70 of bovine pregnancy were compared extensively with corresponding data of the literature. This resulted in an 'embryo/foetal age-scale', which has extended the data in the literature by covering the first 8 to 70 days of pregnancy. This age-scale of early bovine intrauterine development provides model for studies, even when using slaughtered cows without distinct knowledge of insemination or fertilization time, through macroscopic techniques. This distinctly facilitates research into the cow, which is now being widely used as 'an experimental animal' for testing new techniques of reproduction like in vitro fertilization, embryo transfer and cloning.

Expression of IFNAR1 and IFNAR2 in cattle placenta during early pregnancy

“…Cattle uteruses were obtained at 18, 21, 27, 36, 40 and 50 days of pregnancy ( n = 3 samples/stage) for histological observation, immunofluorescence detection and real‐time quantitative PCR (RT‐qPCR). The gestation stage was identified according to the greatest length of conceptus on post‐insemination bovine (Assis Neto et al., ).…”

Bovine yolk sac: from morphology to metabolomic and proteomic profiles

“…Thus, the bovine embryos in Group I had ages ranging from 23 to 32 days of gestation, Group II, of 33-42 days, and Group III, of 43-52 days. The sum of the descriptions of the external characteristics during pregnancy in bovine have been well characterized in the literature for normal pregnancies or in the use of different reproduction techniques such as in vitro fertilization, artificial insemination, and nuclear transfer (Assis-Neto et al, 2010;Alberto et al, 2012).…”

“…Evolutionarily, the yolk sac is the only embryonic attachment present in all vertebrate species and is also responsible for the production of biomolecules essential for embryonic development, including trophic functions for embryo survival (Wolf et al, 2003). Although structurally diverse among different species, particularly in ruminants, the yolk sac is a large, elongated, and vascularized membrane, which is surrounded by extraembryonic cavity (Assis-Neto et al, 2010). In bovine, the yolk sac develops until the 30th day of gestation as a vascularized membrane (Miglino et al, 2006) and remains present until the 50th day of gestation (Assis-Neto et al, 2010).…”

“…Although structurally diverse among different species, particularly in ruminants, the yolk sac is a large, elongated, and vascularized membrane, which is surrounded by extraembryonic cavity (Assis-Neto et al, 2010). In bovine, the yolk sac develops until the 30th day of gestation as a vascularized membrane (Miglino et al, 2006) and remains present until the 50th day of gestation (Assis-Neto et al, 2010).…”

Evolução morfométrica dos anexos embrionários e fetais bovinos obtidos por monta natural, com 10 a 70 dias da gestação

“…Para tal feito, é indispensável que tenhamos bem estabelecida uma caracterização do desenvolvimento normal do processo de placentação inicial em gestações que ocorrem por meio de concepção natural (Assis Neto et al 2009) ou inseminação artificial. Estudos sobre a morfologia do concepto em bovinos têm sido realizados mediante avaliações ultra-sonográfica .…”