Configuration of the portal venous system in agouties (Dasyprocta aguti, RODENTIA)

The study of portal vein concerning the confluent vessels to its formation and its tributaries was carried out in adult agouties (3 females and 7 males), the venous system of which was infected with colored latex and fixed in 10% formol. After dissection, it was noted that the trunk of the portal vein has its origin in the confluence of two roots, represented in 90% of the cases, by the lienal vein and by the common mesenteric trunk, composed by cranial and caudal mesenteric veins and, in 10%, by lienal vein and by cranial mesenteric vein. The trunk of the portal vein has as its tributaries the cranial pancreaticoduodenal vein (100%), the right gastric vein (90%), and the right gastroepiploic vein (40%).O estudo da veia porta quanto aos vasos confluentes para sua formação e suas tributárias foi efetuado em 10 cutias (Dasyprocta aguti), adultas (3 fêmeas e 7 machos), nas quais o sistema desta veia foi injetado com látex corado, sendo a seguir fixadas em formol a 10% e dissecadas. Verificou-se que o tronco da veia porta origina-se sempre pela confluência de duas raízes, sendo representadas em 90% dos casos, pela veia lienal e pelo tronco mesentérico comum, constituído pelas veias mesentéricas cranial e caudal e, em 10%, pela veia lienal e pela veia mesentérica cranial. O tronco da veia porta recebe como tributárias a veia pancreaticoduodenal cranial (100%), a veia gástrica direita (90%) e, ainda, a veia gastroepiplóica direita (40%)

Estudo morfológico e morfométrico do ovário de cutias (Dasyprocta aguti, Linnaeus, 1766)

It were studied 24 ovaries belonging to 13 adult agoutis (in two copies it was just researched the left ovary), being 7 pregnant and 6 not pregnant, coming of the "Núcleo de Estudos e Preservação de Animais Silvestres", of the Federal University of Piauí. The organs were described in loco, measured, submitted to section and observed in Optical Microscope. The ovaries, ellipsoids, were located in the sub-lumbar area, flow to the kidneys, flat, with external surface evidencing small transparent areas and the margin mesovarian and lateral face coming covers for the mesossalpinge (ovaric bag). For the right ovary, was observed on the average: weight - 0,082g; length - 0,83cm; width - 0,49cm and thickness - 0,24cm; the left ovary: weight - 0,058g; length - 0,74cm; width - 0,45cm and thickness - 0,23cm. Histologically, this gonads were correspondents with the majority of the rodents sexually actives studies, showing epithelium of simple cubic coating, the outlying cortex and the central medulla (constituted basically by conjunctive slack tissue mixed with vases of blood). In the pregnant females it was counted two to three great central luteous bodies and many other smaller. In the not pregnant the luteous bodies was smaller and more numerous. The cortex is rich in cellular types of conjunctive nature and follicles in different phases of the maturation, which migration of the mesovarian margin for the tubaric extremity, as they increase of size. It was conclued that the ovaries of the agoutis, macro and microscopically, coming the pattern observed in the others rodents actives sexually.Foram estudados 24 ovários pertencentes a 13 cutias adultas (em dois exemplares pesquisou-se apenas o ovário esquerdo), sendo 7 gestantes e 6 não gestantes, provenientes do Núcleo de Estudos e Preservação de Animais Silvestres da Universidade Federal do Piauí. Os órgãos foram observados in loco para descrição de sua topografia, mensurados, submetidos a cortes histológicos e observados em Microscópio Óptico. Os ovários apresentam-se de forma elipsóide, achatados dorsoventralmente, situando-se na região sub-lombar, caudalmente aos rins, com pequenas áreas transparentes em sua superfície externa. A margem mesovárica e a face lateral estão cobertas pelo mesossalpinge (bolsa ovárica). O ovário direito, apresenta em média: peso - 0,082g; comprimento - 0,83cm; largura - 0,49cm e espessura - 0,24cm; o ovário esquerdo: peso - 0,058g; comprimento - 0,74cm; largura - 0,45cm e espessura - 0,23cm. Histologicamente, constam de epitélio de revestimento cúbico simples, córtex periférico e medula central, constituída basicamente por tecido conjuntivo frouxo entremeado por vasos sangüíneos. Nas fêmeas gestantes foram observados de dois a três grandes corpos lúteos centrais e muitos outros menores periféricos; nas não gestantes os corpos lúteos são menores e mais numerosos. O córtex é rico em tipos celulares de natureza conjuntiva e em folículos em diferentes estágios de amadurecimento, os quais migram da margem mesovárica para a extremidade tubárica à medida que aumentam de tamanho. Conclui-se que os ovários da cutia, macro e microscopicamente, seguem o padrão observado nos demais roedores sexualmente ativos

ASPECTOS ANATÔMICOS DO RIM DE BÚFALOS

A baixa disponibilidade de informações sobre a morfofisiologia de búfalos é um fator limitante para o desenvolvimento da produção desses animais e  por serem importantes na manutenção da homeostase do organismo, os rins merecem particular atenção. Assim este trabalho objetivou estudar a morfologia renal do búfalo da raça Mediterrânea, fornecendo dados para o conhecimento anatômico e fisiológico desse animal. Foram coletados 15 pares de rins de búfalos da raça Mediterrâneo. Injetou-se vinil corado com pigmento vermelho nas artérias renais e gelatina comercial incolor corada com tinta nanquim azul nas veias renais. Descreveu-se a anatomia externa do órgão e em seguida os rins foram dissecados de forma a permitir a observação do comportamento das artérias e veias renais. Observou-se que os rins do búfalo mediterrâneo apresentaram a superfície do órgão divido por fissuras em 30 + 5 lobos, em media, com o direito em formato oval e o esquerdo torcido em seu eixo longitudinal. Tanto a vascularização arterial quanto venosa apresentou variação no numero de ramos hílares, tendo mostrado uma média de 10 artérias e 21 veias hílares. Concluiu-se que os rins do búfalo mediterrâneo apresenta características anatômicas semelhantes ao observado no bovino, porém, com diferenças que permitam a identificação da espécie, como o rim direito menos alongado e as fissuras que dividem os lobos não tão profundas quando comparado aos rins do bovino

Distribuição intraparenquimal da artéria hepática em cutias (Dasyprocta sp, Rodentia)

The present study was design to investigate the hepatic arteries branches and your intraparenchymal distribution in agoutis. Were studied ten agouti's livers, female and male from our colony (Núcleo de Estudos de Preservação de Animais Silvestres do Centro de Ciências Agrárias da Universidade Federal do Piauí - FUFPI/IBAMA 02/99). After injection with colored latex Neoprene 650 (DuPont do Brasil, Chemistry Industries), through the hepatic artery, eight livers were dissected through the visceral faces. The samples were fixed in 10% aqueous formaldehyde solution and after a minimum period of 48 hours. Two organs were injected with colored vinil acetate, following procedures of acid chloride corrosion in order to obtained vascular casts. The study shows that the agouti's hepatic arteries bifurcate into two principals branches, right and left (100%). In general, the right branches usually (80%) gave origin vessels that are responsible for the right medial, right lateral and caudate lobes's vascularization. The left branches normally (80%) give origin vessels that are responsible for the left medial, left lateral, quadrate lobes's vascularization, also to the caudate lobos (50%) and right lateral (20%). In this way, the vascular distribution of the hepatic artery is related to the organ's lobos; where the right and left branches have intraparenchymal distribution into the liver's lobos. This study gave support to the anatomic-surgery artery segmentation.Com o objetivo de analisar a ramificação da artéria hepática e sua distribuição intraparenquimal em cutias, foram utilizados dez fígados de cutias adultas, fêmeas e machas, cedidas pelo Núcleo de Estudos e Preservação de Animais Silvestres do Centro de Ciências Agrárias da Universidade Federal do Piauí (Convênio FUFPI/IBAMA número 02/99). Oito fígados foram dissecados pela face visceral após injeção com látex do tipo Neoprene 650 (DuPont do Brasil Industrias Químicas) corado em vermelho, através da artéria hepática, e fixados em solução aquosa de formol a 10%, durante pelo menos 48 horas. Dois órgãos foram utilizados para a confecção dos moldes vasculares, através de injeção de solução de acetato de vinil corado em vermelho e corrosão em solução aquosa de ácido clorídrico a 30% até total destruição do parênquima. O estudo das peças mostrou que a artéria hepática na cutia divide-se em dois ramos principais, direito e esquerdo (100%). De forma geral, o ramo direito predominantemente (80%) origina vasos responsáveis pela vascularização dos lobos medial direito, lateral direito e caudado. O ramo esquerdo apresenta-se com maior freqüência (80%) constituindo um tronco comum aos vasos que se destinam aos lobos lateral esquerdo, medial esquerdo, quadrado, em 50%, também ao lobo caudado e em 20% ao lobo lateral direito. Sendo assim, conclui-se que a distribuição vascular da artéria hepática está relacionada à lobação do órgão, onde os ramos direito e esquerdo se distribuem no parênquima dos lobos do fígado, podendo-se inferir a presença de territórios com vascularização própria nos lobos hepáticos, caracterizando, portanto, a segmentação anátomo-cirúrgica arterial

Medullary Conus Topography in White-Tufted-Ear-Marmoset (Callithrix jacchus)

Background: The common marmoset (Callithrix jacchus) belongs to the family Cebidae and Subfamily Callitrichinae, a group formed by the smallest anthropoid primates. It is a very common species and adapts easily to captivity, an aspect that encourages the clandestine capture of these animals and makes them susceptible to wounds resulting from clandestine rearing and inadequate management, so that studies to understand the species are extremely important.  With the objective of supplying anatomic bases for the practice of epidural anesthetic, data were studied regarding the topography of the common marmoset (Callithrix jacchus).Materials, Methods & Results: The study was carried out at the Laboratory of Veterinary Anatomy at the Federal University of Campina Grande (UFCG), PA, Brazil. Ten adult common marmosets (Callithrix jacchus) were used, 5 males and 5 females, with different causes of death. A round workbench magnifying lamp was used to better visualize the dissecation field.  Number 15 scalpel blades, surgical pincers and scissors were used to dissect.  After fixing in 10% formaldehyde aqueous solution, dissecation was made along the mid dorsal line, from the cranial thoracic region to the tail base to expose the vertebral arches and measure the intervertebral spaces.  The vertebral arches were removed, and consequently the spinal dura mater was exposed, that was sectioned longitudinally to expose the spinal chord and identify the lumbar intumescence, the conus medullaris and the cauda equina. The length of the conus medullaris was measured and its skeletopy was established. The body and tail length data were submitted to analysis of variance and the means were compared by the Tukey test at 5% probability. The mean value of the conus medullaris length was 1.4 cm, while the anatomic location of the conus medullaris varied slightly among the animals, but did not pass the limit between L3 for the base and L6 for the apex. On average, the lumbosacral space measured 3.03 mm, that is sufficient to introduce a needle similar to that used in syringes for insulin injection. The results of this study suggest the lumbarsacral space as location for epidural anesthetic application in Callithrix jacchus, at a safe point situated in the center of an isosceles triangle, the base of which is found when a line is drawn from one side of the pelvis to the other, and the apex corresponds the spinal process of the first sacral vertebra.Discussion: The anatomic location of the conus medullaris is different compared to two other primate species, the red handed tamarin (Saguinus midas), in which the cone base was registered at L4 and the apex at S2, and the common squirrel monkey (Saimiri sciureus) where the conus medullaris base occurs at L7-8 and the apex at S3 or Cc1. However, some similarities with other mammal groups were observed in the conus medullaris topography, such as the black-striped capuchin (Sapajus libidinosus). The mean conus medullaris length of the species Callithrix jacchus of 1.4 cm was close to that observed in the coypu, capuchin monkey and sloth, and significantly smaller than the means obtained for the red handed tamarin and common squirrel monkey and other non-primate mammals reported in the literature. The lumbosacral space is the location indicated for epidural anesthesia in Callithrix jacchus, that has also been indicated for other wild mammals such as the black-striped capuchin monkey (Sapajus libidinosus), the maned wolf (Chrysocyon brachyurus), the tayra (Eira barbara), the giant otter (Pteronura brasiliensis), the crab-eating racoon (Procyon cancrivorus) and the coypu (Myocastor coypus)

Morfologia dos órgãos genitais externos do macho de cutia (Dasyprocta aguti. Linnaeus, 1766)

Thirty-thee males adult agoutis (Dasyprocta aguti) had been used, originated from the Universidade Federal do Piauí (UFPI) - Piauí State, and from the Escola Superior de Agricultura de Mossoró (ESAM) - Rio Grande do Norte State - Brazil. The purpose of the present investigation was describly the morfology of male genital organs and caracterized the histology aspects and their gross caracteristics. It was carry out an dissections of the extenal organs genital. The fragments were included in paraffin and stained with hematoxylin-eosin and Tricomy of the Masson and observed in light microscopic .The result showed that the penis is fibrocavernous with large amounts of the keratizaded structures in the their apex. In third part of the penis was evidencied an curved with form of the "U" lying. The glans was covering to keratinized epiderm with many espicules, an bone penis has been replaced the carvernous body. In the part ventral of the penis there was suburethal sac with two long projection corneus. In the Scroral region there wasn't distintict external limits with scrotum. Under of the internal layer of the prepuce, next to the preputial orifice, there was two preputial gland.Foram utilizados vinte e três cutias (D. aguti), machos, adultos, adquiridos em criatórios científicos, legalmente licenciados pelo IBAMA, da Universidade Federal do Piauí - UFPI, Teresina, PI e da Escola Superior Agrícola de Mossoró - ESAM, Mossoró, RN, com o objetivo de descrever morfologicamente os órgãos genitais masculinos externos, abordando aspectos histológicos e macroscópicos destes órgãos. Foi realizada a dissecação dos órgãos genitais externos dos espécimes. Fragmentos foram coletados e submetidos ao processamento histológico de rotina para inclusão em parafina, os quais foram cortados e corados pelos métodos de H/E e Tricômico de Masson e observados em microscópio de luz. Os resultados mostraram que o pênis destes animais possui características do tipo fibrocavernoso, com grande quantidade de estruturas queratinizadas no seu ápice. No terço médio do pênis da cutia foi evidenciado uma flexura peniana em forma de "U" deitado; a glande do pênis encontra-se revestida por uma epiderme queratinizada contendo espículas córneas; um osso peniano substituindo o corpo cavernoso e um saco suburetral ventral, com dois longos esporões córneos no seu interior, estão presentes no pênis desses espécimes. Na região escrotal não se observa limites externos nítidos do escroto. Dorsalmente, abaixo da lâmina interna do prepúcio, próximo ao óstio prepucial, verifica-se um par de glândulas prepuciais

Morphometry and Cardiac Anatomicalsurgical Segmentation in Goats

Background: Although surgeries that remove of part of the heart wall are not yet part of veterinary and human surgical routine, experimental studies can indicate this practice in cases where alterations are identified in the heart morphology, with the determination of the heart segments that are part of the organ with independent vascularization and irrigation.  In this context, the objective of the present study was to describe the anatomic surgical segmentation of the goat heart and supply biometric data on the heart to enrich data on the heart morphology of this species.Materials, Methods &Results: Twenty-six hearts were used from crossbred goats, ten to assess the topographical relations of the heart and morphological description of the organ; ten hearts were weighed on  0.01 g precision semi-analytical scales, measured with a pachymeter and later Agar-Agar was injected in the cavities which were sectioned crosswise to establish the volumetric proportion of the heart components, applying a point counting grid to the base surfaces; in three hearts natural latex was injected in the coronary arteries, that were later dissected, and red-stained vinyl acetate was injected in three,  corroded in acid to make vascular molds and these two groups were used to define the irrigation territories of the coronary arteries, identifying the anatomic surgical units among the animals studied.  The goat heart presented average weight of 126.6 g, 8.36  ± 0.62 cm length and 5.89 ± 0.57 cm width at the base.  The study of the volumetric proportion showed that the proportion of muscle was 75.87% and the cavity proportion was 24.12%; the arterial volume (13.94% ±3.01) was greater than the ventricular volume (6.32% ± 1.43). An average of 13 ventricular segments were identified from the vascular study, coming from the right and left coronary arteries that were characterized as SAIP -  Interventricular Paraconal Arterial Segment; SAVE1-  Left Ventricular Ventral Arterial Segment; SAVE2- Left Ventricular Ventral  Arterial Segment; SAME- Left Ventricular Margin Arterial Segment; SAVD1- Right Ventricular Ventral Arterial Segment, SAVD2 - Right Ventricular Ventral Arterial Segment, SAIS- Subsinuosus Interventricular Arterial Segment, SAA- Adipose Artery Arterial Segment, SADE1- Left Ventricular Dorsal Arterial Segment, SADE2- Left Ventricular Dorsal Arterial Segment 2- SAMD: Right Ventricular Margin Arterial Segment, SADD1- Right Ventricular Dorsal Arterial Segment, SADD2- Right Ventricular Dorsal Arterial Segment.Discussion: The goat hearts presented anatomy and topography according to that described in the literature for the species.  Regarding the heart morphology and segmentation, the goat is similar to the dog, and the goat can be used as an experimental model in cardiology research. As the segments identified presented few variations among the animals, observing that some of them were not found in 100% of the sample, but understanding that the goat arterial segments are well defined in the heart wall, the data was considered  reliable for future research of partial ventriculectomies

Análise qualitativa do estabelecimento da espermatogênese em cutias (Dasyprocta aguti) criadas em cativeiros

A determinação do estabelecimento da puberdade é bastante estudada em animais domésticos e roedores, no entanto, são escassas as pesquisas com a finalidade de estabelecer parâmetros para a biologia reprodutiva em cutias. Foram utilizadas 31 cutias machos da espécie Dasyprocta agouti, oriundas da Universidade Federal do Piauí, Estado do Piauí, e da Escola Superior de Agricultura de Mossoró, Estado do Rio Grande do Norte. Imediatamente após a orquiectomia foram retirados fragmentos e estes foram processados histologicamente, os tecidos foram corados com hematoxilina-eosina e analisou-se os parâmetros seguintes: aspectos de luminação dos túbulos seminíferos; presença de espermatócitos primários; presença de espermátides e formação dos primeiros estágios do ciclo do epitélio seminífero (CES) segundo o método da morfologia tubular. O período desde o nascimento até os cinco meses de idade correspondeu à fase impúbere; dos seis aos oito meses de idade a fase de transição da pré-puberdade à puberdade; dos nove aos dez meses de idade à fase da puberdade; e dos doze aos quartoze meses de idade à fase da pós-puberdade. A puberdade da cutia (Dasyprocta aguti), ocorreu em animais a partir dos sete meses de idade, e o estabelecimento da puberdade foi constatado em todos os animais estudados aos nove meses de idade.The determination of the puberty beginning is widely studied in domestic animals and rodents. However, there are scarce researches with the purpose to establish parameters for the reproductive biology in Agoutis. Thirty-one male Agoutis, Dasyprocta agouti species had been used, originated from the Universidade Federal do Piauí - PI, and from the Mossoró Superior Scholl of Agriculture - RN. Immediately after the orchiectomy, histological sections were made, the tissues were stained with hematoxylin-eosine and analyzed for the following parameters: aspects of the seminiferous tubule lumen; presence of primary spermatocytes; presence of spermatid cells and formation of the first stages of the seminiferous epithelium cycle (SEC), in accordance with the tubular morphology method. The period from the birth up to five months of age corresponded to the impuberal phase; from six to eight months, to the transition from the prepuberal phase to puberty; from nine to ten months, to the puberty; and, from twelve to fourteen months of age to the after-puberty phase. The puberty of the Agouti (Dasyprocta aguti), occurred since seven months of age, being the establishment puberty beginning evidenced at nine months of age

Anesthesia of Agoutis (Dasyprocta prymnolopha) with Dextroketamine and Midazolam

 Background: Research has increasingly focused on wild animals, and this requires the use of chemical restraints that are safe for both the species and the team involved. Dextroketamine is the levorotatory ketamine isomer that has been used on domestic species as an alternative that is more potent and safer than the racemic form. Midazolam is a benzodiazepine that induces muscle relaxation and minimal cardiorespiratory changes. The purpose of this study was to determine whether a combination of dextroketamine and midazolam can be safely used for the chemical restraint of agoutis (Dasyprocta prymnolopha), and the effects of this protocol on physiological and anesthetic parameters. Materials, Methods & Results: This study was carried out under conditions similar to those found for wild animals in captivity or in zoos. A pre-evaluation was also made to compare the baseline values of this study with those of other studies on the same species. Nine healthy adult agoutis were used, weighing between 1.5 kg and 2 kg. All the parameters were evaluated and recorded before the drugs were applied, and this was considered the baseline moment (M0). The dextroketamine and midazolam combination was then administered intramuscularly, in the same syringe, in dosages of 15 mg/kg and 0.5 mg/kg, respectively. Successive evaluations were made every 10 min over a period of 40 min (M10, M20, M30 and M40). The latency stage of anesthesia, effective stage and recovery stage were observed. Heart rate (HR) and breathing frequency (f), body temperature (BT), systolic blood pressure (SBP), peripheral oxygen saturation (SpO2) and electrocardiogram were recorded. HR and SBP showed no significant difference between moments. Breathing frequency (f) showed a significant decline at M10 and M20 when compared to baseline values (P < 0.05). BT decreased from the moment the drugs were administered until the end of the experimental period, with a significant difference between M0 and M40, and M10 and M40 (P < 0.05). SpO2 decreased significantly at M10 and M20 when compared to baseline values (P < 0.01). There was no significant difference in the duration and amplitude of the P wave or in the duration of the QRS complex, QT interval and amplitude of the R wave. Regarding the PR interval, there was a significant difference only at M40 when compared to baseline values (P < 0.05). No arrhythmia was observed. An evaluation of the effects of anesthesia indicated that the animals had an average latency stage of 2 min, an effective stage of 87 min, and an average recovery stage of 111 min. Adverse effects observed during the anesthetic recovery period consisted of tearing, salivation, tongue protrusion, vocalization and chewing reflex. Discussion: The results indicated that the association of anesthetic drugs under study caused minimal changes in the animals’ physiological parameters, except for the breathing frequency (f), which declined considerably, resulting in a reduction in SpO2, which was compensated during the study. In addition, there was a rapid onset of restraint and a satisfactory duration. Thus, from the cardiorespiratory standpoint, the combination of dextroketamine and midazolam in the doses used provides a safe anesthetic protocol for agoutis (Dasyprocta prymnolopha) and can be used for the chemical restraint of these animals for the performance of non-invasive and short-term procedures

Macroscopic Anatomy and Brain Vascularization in the Greater Rhea (Rhea americana americana)

Background: The Rhea americana americana is a wild bird belonging to the group of Ratites, and is important from the scientific point of view given their adaptability to captivity. Considering that information about its morphology is important for the viability of domesticating the species, the aim of this study was to macroscopically identify the brain regions, as well as the cerebral arteries and the cerebral arterial circuit in order to establish the cerebral vascular pattern and systematization.Materials, Methods & Results: Twenty one brains from young and adult Greater Rheas of both sexes were used from animals that had died due to natural causes and were then kept in a freezer. The specimens were thawed and incised in the cervical region to allow exposure of the left common carotid artery, which was cannulated. The vascular system was rinsed with 0.9% saline solution, then perfused with latex Neoprene 650 stained with red pigment. The animals were subsequently fixed in 3.7% aqueous formaldehyde solution for 72 h, and then they were dissected by removing the bones from the skull cap. The brains were analyzed, and the structures were identified, photographed, schematized and denominated. Morphometric measurements were performed on the basilar and cerebellar ventral caudal arteries, recording the values of length and width in millimeters with the aid of a digital caliper. The brain was divided into: telencephalon, diencephalon, brainstem and cerebellum; while externally, the observed structures are: olfactory bulbs, optical lobes, optic nerves, optic chiasm, pituitary and pineal glands. Vascularization was performed by the following arteries: ventral spinal artery, basilar artery, ventricular cerebellar arteries, medium ventricular cerebellar arteries, caudal branches of the carotid arteries of the brain, ventral mesencephalic artery, cerebral caudal arteries, rostral branches of the carotid arteries of the brain, middle cerebral arteries, cerebroethmoidal arteries, rostral intercerebral anastomosis, rostral cerebral arteries, ethmoidal arteries, internal ophthalmic arteries, inter-hemispheric artery, pituitary arteries, dorsal mesencephalic tectal arteries, dorsal cerebellar arteries, occipital, pineal and dorsal hemispherical branches. The cerebral arterial circuit was both caudally and rostrally closed in 100.0% of the samples, being composed of the arteries: basilar artery, caudal branches of the carotid brain, rostral branches of the brain carotid, cerebroethmoidal arteries and rostral intercerebral anastomosis.Discussion: Encephalon classification regarding the presence or absence of gyri is a characteristic associated to evolutionary aspects among vertebrates, being respectively considered as lisencephalon or girencecephalus when it presents or does not present convolutions. In Greater Rheas, the telencephalon was quite developed, with a relatively rounded shape and the absence of sulci and convolutions in the cortex, which allowed it to be classified as a lisencephalon. Such findings resemble those described for the ostrich and in a comparative study involving kiwis, emus, owls and pigeons, although different sizes and forms of telencephalon development were observed in the latter. Regarding the cerebral arterial circuit, this structure in Rheas was complete and both caudally and rostrally closed in 100.0% of the specimens. Our findings differ from those observed for ostriches, in which a rostrally open behavior has been described, while it is caudally closed in 20.0% of cases and opened in 80.0%. Regarding the vascular type of the brain, in the Rhea it was observed that there was only contribution of the carotid system, similar to that found for birds such as ostriches and turkeys which confer a type I encephalic vascularization