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We studied the development of respiratory tract in bovine embryos by light microscopy and transmission electronic microscopy. This process was observed formation of laryngeal-tracheal tube in embryos that present crown-rump (CR) length of 9.0 mm (20/21 days of pregnancy) at around the fourth gestational week; the organ wall appears to be formed of epithelium comprising several cell layers and supported by mesenchyme. Within the lungs, the areas subjacent to epithelium present condensed mesenchyme, while more distal areas loose mesenchyme, in which blood vessels beginn to form, as the organ is in a pseudo-glandular phase. Ultra-structurally, the mesenchyme cells present irregular shapes, having a stellar or fusiform appearance and are united by desmosomes, where the cytoskeleton attaches to the cellular membrane, forming a connection. The bifurcation of trachea caudal portion in the main bronchia is simultaneous to the appearance of the tracheal bronchi, during the fifth gestational week.

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Background: Embryonic mortality is a major cause of reproductive failure in cattle, resulting in a lot of problems to the industry. Recently, many techniques have been used in the production of genetically modified animals mainly related to improve the animal production. The possibility to genetically manipulate living organisms through the addition or inactivation of genes has revolutionized the understanding of biological and molecular mechanisms. Herein, we showed data about what is known about the abnormalities in bovine conceptus using IVF and NT techniques. Review: The establishment of pregnancy results from the interaction between the trophoblast and maternal tissues. Embryonic/ fetal loss occurs throughout pregnancy in cattle; however, it is concentrated mainly in the first 42 days after breeding. Recently data have showed that approximately 50% of cloned bovine embryos do not establish the gestation after the transference of the blastocyst. In addition, placental abnormalities occur in high levels in cloned animals during the initial and in the end of gestation. Low viability of cloned embryos is mainly expressed by the reduction in the rate of deployment, the increased rate of perinatal mortality and fetal, and the various anomalies observed in newborn animals. Among the pregnancy complications from placental transfer of manipulated embryos (IVF and NT) there are changes in the morphology of the placentome, in the region of the fetal-maternal contact, increase of allantoic or amniotic fluid, vascularity, lower number of cotyledons, and increased of the interplacentomal area "Offspring Syndrome". In addition, the placenta, fetal membranes and umbilical cord from cloned animals have rudimentary development. According to Wells et al., the overall efficiency of cloning in bovine is limited to 5- 6%. In IVF pregnancies the placentome percentage, fetal villi, density and volume of binucleated cells is reduced. However, the volume of blood vessels in increased maternal wattles, believing there is a compensatory mechanism in the vascular network of the placentae. Conclusion: Many technological innovations could help to obtain a better quality production and significant improvements in animal breeding such as those brought about by nuclear transfer and in vitro fertilization. New studies on the dynamics of development in cattle embryology derived from nuclear transfer techniques and in vitro fertilization are necessary, focusing on different systems in order to find greater success in the artificial producing and selection of interest characteristics.

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O tatu-peba é um animal solitário, que habita campos, cerrados e bordas de floresta onde escava túneis para se esconder. Ao contrário de muitas outras espécies de tatus, esta frequentemente reutiliza suas tocas, pois possuem a proteção de uma forte carapaça rígida e extremamente queratinizada, conectada ao corpo por uma pele grossa e córnea. Sendo os tatus animais escavadores, as quais são possíveis de comprovar neste estudo, que todas as estruturas e acidentes ósseos de seu esqueleto encontram-se voltados unicamente para o seu modo de vida. A escápula, obteve 8,0 cm de comprimento médio longitudinal, 6,0 cm vertical desde seu ângulo caudal ao final da fossa supra espinhosa e com 2,5 cm, com origem junto ao acrômio. O úmero apresentou um epicôndilo lateral longo (2,0 cm), com mensuração da tuberosidade deltóide de 1,0 cm, sendo muito desenvolvida onde se insere seu próprio músculo deltóide. O úmero apresentou 6,0 cm de mensuração longitudinal média. O rádio trata-se de um osso curto, com 4,0 cm de mensuração longitudinal e 0,5 cm vertical. Já a ulna apresenta um olécrano longo, com mensuração de 2,5 cm longitudinal e 1,0 cm vertical. Os ossos carpais, metacarpais e falanges são bem curtos, não possibilitando mensurações. No membro pélvico, o fêmur apresentou o primeiro, segundo e terceiro trocanter. Sendo o terceiro bem desenvolvido, projetado lateralmente com 2,5 cm longitudinalmente e obteve-se 9,0 cm de comprimento para o osso fêmur. A patela com 1,8 cm de comprimento. O corpo da tíbia apresenta projeção de 1,0 cm para a lateral e 14,0 cm² de área de separação do corpo da fíbula. A mensuração longitudinal da fíbula e tíbia é de 7,0 cm se encontram fundidas. A sétima ou última vértebra cervical forma com a primeira vértebra torácica, um assoalho ósseo, denominado de processo transverso, onde existe um grande forame dorsal gerando um triângulo com 1,2 cm de altura (0,96 cm² de área). Dez vértebras torácicas, sendo estas relativamente pequenas, com processos espinhosos pequenos, delgados e inclinados caudalmente. O osso sacro deste animal pode ser chamado de sinssacro, devido a forma ser semelhante as aves, e por ultimo, presença de cauda longa e pesada, com 26,0 cm de comprimento, e diminuição gradativa no tamanho de suas vértebras.

The Armadillo is a solitary animal. It occupies fields, cerrados and forest edges where excavates tunnels to hide in. Unlike many other species of sloth, this often reuses its toggling, because they have a strong protection of rigid and extremely keratinized carapace connected to the body by a thick and cornea skin. It could be demonstrated in this study that all bone structures and accidents of PNAS are targeted solely to their way of life. The scapula had 18.0 cm longitudinal, 6.0 cm vertical from the caudal angle to the end of the supra spinous fossa and 2.5 cm from the origin of the acromion. The humerus presented a long lateral epicondyle (2.0 cm), the deltoid tuberosity was 1.0 cm, much developed in the kite muscle. The humerus presented 6.0 cm longitudinal. The radio is short, a bone with 4,0 cm longitudinal and 0,5 cm vertical. But the ulna presents a long olecranon, with 2.5 cm longitudinal and 1.0 cm vertical. The carpais, metacarpais and phalanges are very short, not allowing measurements. The femur presents the first, second and third trochanter, being the third well developed. Designed laterally with 2.5 cm lengthwise, it was 19.0 cm long. The patella was 1.8 cm long. The body of the tibia presented 1,0 cm of projection for the side plane and 14.0 cm² picking area of the body of the fibula. The measurement of the tibia and fibula was 7.0 cm longitudinal, and they are rendered. The seventh or last cervical vertebra with the first thoracic vertebra is a bone floor named transverse process, in which there is a large dorsal foramen forming a triangle with 1.2 cm height (0.96 cm² area). There are ten relatively small thoracic vertebrae with small, thin and inclined neural spines. The holy bone of this animal may be called sinsacro, because its form is similar to birds, presence of long and heavy tail with 26.0 in long and gradual decrease in the size of the vertebrae.

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