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Distress can be defined as a biological response of an individual to long-term threats to its homeostasis and it should be avoided from an animal welfare perspective. High levels of stress hormones and the expression of abnormal behaviours are responses normally observed in distressed animals. Captive environments can provoke distress, especially when inappropriate stimuli are provided to the animals. The concomitant use of behavioural and non-invasive hormonal measures is a means to evaluate captive animal welfare. Environmental enrichment is a tool that can reduce distress and minimize the expression of abnormal behaviour in captive animals. The aim of this study was to evaluate greater rheas' responses (behavioral and hormonal) to food-based enrichment. Three birds from the Belo Horizonte Zoo, Brazil were studied. The study was divided into three phases (baseline, enrichment and post-enrichment): fruits scattered around the birds' enclosure were used as enrichment. Behaviour and faecal sampling were undertaken in all phases of the study. Abnormal behaviours and faecal glucocorticoid metabolites (GCM) levels showed significant reduction during the environmental enrichment phase, and a significative positive correlation between GCM production and abnormal pacing was observed. From the results of this study, we conclude that the use of food as environmental enrichment should be encouraged because of its positive effects on animal welfare. Besides, studies with larger groups of greater rheas, with individuals of both sexes, should also be encouraged to evaluate if the results found in this pilot study are consistent and can be generalized to the species. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to study the morphological pattern of bone maturation of the hindlimb bones of Rhea americana and find out how it can affect bone morphology after a taphonomic process. Juvenile specimens (n = 10) ranging from one month old to eight months old were studied. For comparison, bones from adults and juveniles from museum specimens (n = 4 and n = 6, respectively) were studied. In fresh bones, ossification centres were identified in the proximal and distal epiphyses of the tibiotarsi and in the proximal epiphysis of the tarsometatarsi, whereas the distal region of the femora and tarsometatarsi showed abundance of cartilage. The development and extension of the ossification centres of the tibiotarsi were different. In the proximal epiphysis, the centre presented less development with respect to the distal epiphysis. In the dry tibiotarsi, the proximal centre was absent and the distal one was well preserved. Both the fresh and dry juvenile tarsometatarsi presented unfused metatarsals and bulkier and wider aspect than the adult ones. The dry femora presented a noticeable excavation between condyles, whereas the dry tarsometatarsi showed the absence of the proximal epiphysis. The femora, tibiotarsi and tarsometatarsi possessed different traits of immaturity, which differentially affect the morphology of the preserved bones during a taphonomic process. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Birds have genomic and chromosomal features that make them an attractive group to analyze the evolution of recombination rate and the distribution of crossing over. Yet, analyses are biased towards certain species, especially domestic poultry and passerines. Here we analyze for the first time the recombination rate and crossover distribution in the primitive ratite bird, Rhea americana (Rheiformes, Palaeognathae). Using a cytogenetic approach for in situ mapping of crossovers we found that the total genetic map is 3050 cM with a global recombination rate of 2.1 cM/Mb for female rheas. In the five largest macrobivalents there were 3 or more crossovers in most bivalents. Recombination rates for macrobivalents ranges between 1.8–2.1 cM/Mb and the physical length of their synaptonemal complexes is highly predictive of their genetic lengths. The crossover rate at the pseudoautosomal region is 2.1 cM/Mb, similar to those of autosomal pairs 5 and 6 and only slightly higher compared to other macroautosomes. It is suggested that the presence of multiple crossovers on the largest macrobivalents is a feature common to many avian groups, irrespective of their position throughout phylogeny. These data provide new insights to analyze the heterogeneous recombination landscape of birds. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Eggs have protective structures against possible contamination by bacteria and fungi. Pathogenic bacteria such as Salmonella spp. are therefore rarely found in adequate sanitary conditions. Few studies about the contamination of ratite eggs have been reported, and although some studies have focused on ostrich eggs, there is no information about Greater Rhea (Rhea americana) eggs. The microorganisms that contaminate ratite eggs do not differ from those that affect other bird species. The purpose of this study was to characterise contamination in 16 eggs, supplied by a commercial breeding facility, by Enterobacteriaceae contamination and to assess the in vitro resistance to experimental contamination by Salmonella Enteritidis using analytical tests following the guidelines of the Georgia Poultry Laboratory. These elements are critical to the storage period, quality and physicochemical parameters. The results revealed the presence of the genera Proteus, Klebsiella, Citrobacter and Enterobacter related to the location of nests. Greater Rhea eggs were also found to be highly resistant to experimental infection by Salmonella Enteritidis. [ABSTRACT FROM AUTHOR]

The abundance and spatial distribution of species are influenced by the distribution and availability of resources. The objective of this study was to evaluate habitat selection by a wild population of Greater Rhea (Rhea americana) in El Palmar National Park, Entre Ríos, Argentina, and the adjacent agroecosystem. Sightings and signs (i.e. faeces, footprints) of Rheas and environmental variables were recorded every 45 days from April 2011 to March 2012 at 51 sites. The associations between the habitat selected by Rheas and landscape elements were analysed by means of generalised linear mixed models and generalised linear models. A total of 301 sightings were made, at 57% of the sampling sites. Habitat use was linked with environmental variables but differed with time of year (breeding vs non-breeding season). For much of the year, Rheas selected sites with a simple landscape structure, open and low vegetation, such as grasslands, crops and firebreaks, which facilitate movements of birds, and near waterbodies. In the breeding season, Rheas selected dense grassland sites. To manage and conserve this species, it is recommended that areas of open grassland free of shrubs are preserved and expanded and that grassland corridors are created to connect fragmented patches of grassland. [ABSTRACT FROM PUBLISHER]

Sinusitis is a common finding in avian species; however, it presents unique treatment challenges in ratites. A 6-yr-old male greater rhea ( Rhea americana) presented acutely with right infraorbital sinus swelling and chemosis. Oral antibiotics were prescribed based on bacterial culture results with incomplete resolution of clinical signs. A computed tomography scan of the skull demonstrated a mixed-density soft tissue mass with extensive destruction of the right nasal bone, hard palate, maxilla, and frontal bone. The affected tissue was surgically resected and histopathology was consistent with inspissated necrotic tissue. Aerobic culture of the mass grew a multidrug-resistant Escherichia coli and was treated with amikacin. Ten months postsurgery, no further clinical signs were observed. Advanced diagnostic imaging with computed tomography and surgical therapy facilitated complete resolution of this resistant bacterial sinusitis in a species that is not typically amenable to frequent handling and restraint. [ABSTRACT FROM AUTHOR]

Copyright of Pesquisa Veterinaria Brasileira is the property of Colegio Brasileiro de Patologia Animal - CBPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to describe the histological structure of the skin of greater rhea (Rhea americana), a ratite bird native to South America. Skin samples were taken from three regions of the trunk (alar, dorsal and pelvic) in 14 specimens which ages ranged from 7 days to adulthood. Serial sections were obtained and subjected to different staining procedures (haematoxylin and eosin, orcein, Masson's trichrome and Gomori), and a morphometric analysis was carried out on stained slides. In general, both epidermis and dermis showed increased thickness of its layers with age. Some differences between regions can be detected both in epidermis and in dermis; for example in adults and 7-dayold birds, the stratum corneum of the alar region was thicker than of the dorsal region. In general, the skin of greater rhea was similar to that described in ratites and other birds (a thin epidermis compared to dermis, dermis with scarce elastic fibres, a slender and vascularized stratum superficiale, collagen fibres arranged in three directions). The scarcity of elastic fibres and the general cross-weaved arrangement of the collagen fibres in the dermis of the adult greater rhea provide strength and flexibility to the dermis, two important features in leather industry. [ABSTRACT FROM AUTHOR]

Translocation is an extensively used conservation tool that involves exposing animals to stressful situations that may influence the post-release survival. In this study, 20 Greater Rhea ( Rhea americana) adults hatched and reared in captivity were translocated to a wildlife refuge. After transport and before release, animals were kept in pens at the liberation site to make a 'soft-release' strategy. Fecal glucocorticoid metabolites (FGM) were monitored during pre-transportation, post-transportation and pre-release, and post-release phases as an indicator of the stress of translocation and acclimation to the new environment. During pre-transportation phase, FGM levels found were consistent with the baseline concentrations described for this species for males and females, respectively. On day 1 after transportation, FGM levels were increased in both sexes, returning to baseline values during the maintenance in the pens. Although the handling and transportation triggered an acute stress response, the procedures used and the soft release in pens allowed Rheas to reestablish quickly baseline FGM levels. After release into the novel wildlife refuge, FGM levels were increased again and remained similarly increased during the following 2 months of the study. Findings suggest a strong chronic stress response, probably triggered by a combination of many factors (i.e. novelty, attacks from predators, social interactions, human related disturbances such as poaching, vehicular noise, hunting dogs) that may reduce the bird's ability to solve new challenging situations, especially the illegal hunting pressure that seems to be a significant threat in this species. [ABSTRACT FROM AUTHOR]

The greater rhea ( Rhea americana) is the largest South American bird. It is a cursorial, flightless species with long powerful legs and reduced forelimbs. The goal of this study was to explore how hindlimb muscles scale with body mass during postnatal growth and to analyze whether the specialized locomotion of this species affects the growth of muscle masses. The mass of 19 muscles and body mass were weighed in 21 specimens ranging from 1-month-old individuals to adults. Seventeen muscles scaled with positive allometry with respect to body mass, whereas two muscles scaled isometrically . The predominance of positive allometric growth in hindlimb muscles results in a limb with massive and powerful muscles specialized to support a large body mass and to attain relatively high running speeds. Analysis of muscle mass scaling is a simple and useful way to compare possible differences between locomotor styles, and it is valuable in studies that reconstruct the paleobiology of extinct taxa. [ABSTRACT FROM AUTHOR]

Knowledge of wild species embryonic development is important for their maintenance in captivity or the wild. The objective of the present study was to characterize the external morphology and define the biometry of greater rhea embryos and fetuses at different stages of development. A total of 41 embryos and fetuses were analyzed to describe their external morphology using a stereoscopic microscope. The crown-rump (CR), total length (TL), cephalocaudal length (CCL), biparietal diameter (BPD), beak, humerus and tibio-tarsal lengths were measured by digital pachymeter, millimetric scale ruler and cotton thread. The weight of the embryos and fetuses was measured on digital scales. The greater rhea embryos at 5, 6 and 7 days incubation presented a “C” shape. At 9, 10 and 11 days the eyes were big and pigmented. At 11, 12 and 13 days the eyelid covered more than half the eye, resulting in an oval slit. In 14 and 15 day-old embryos, the skin was still thin and the ribs evident, but at 18 days this structure was thicker. In embryos at 21 and 27 days of development closed eyelids were observed forming an eyelid slit, and the eye ball was less pronounced at 27 days. Weight gain presented an exponential growth curve, while measurements such as TL, DBP, beak, humerus and tibio-tarsal length had linear growth over time. Thus it was possible to characterize the greater rhea embryos and fetuses at several incubation ages using their external morphology and morphometric analyses. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Greater Rhea (Rhea americana) is a member of Brazilian fauna with potential for the production of eggs with a unique nutritional composition that differs from the eggs of other species. The present study aimed to gather information regarding the centesimal composition of Greater Rhea eggs and the storage time for the preservation of egg quality for human consumption. Twenty-five Greater Rhea eggs (albumen and yolk fractions), distributed into five groups of eggs stored for 7, 14, 21, 28 and 35 days at 10 °C, were analysed. For the determinations of the percentage composition, total protein was quantified by the Kjeldahl method and total lipids by the Soxhlet method. To assess egg quality, the Haugh unit (HU), pH, and protein degradation (by SDS PAGE electrophoresis) were determined. Based on the results, the albumen protein fraction quality was maintained for 21 days, while the yolk proteins began to denature on the 14th day. The total lipids of the albumen and yolk fractions did not change significantly until the 35th day of storage; at this time, the quality decreased significantly, indicating that the eggs were adequate for consumption until the 28th day. Considering the protein degradation profile and internal quality, Greater Rhea eggs can be stored for 21 days at 10 °C without alteration of their nutritional or functional characteristics. [ABSTRACT FROM AUTHOR]

The purpose of this research was to study the macroscopic testicular and epididymal morphology of the greater rhea. The testicles of 54 greater rhea bred in captivity were utilized. The samples were collected November 2005 ( n = 14), December 2006 ( n = 20) and May 2007 ( n = 20). During commercial slaughter, the testicles and epididymides were collected and their following morphometric parameters were immediately measured: length, width, thickness, circumference, volume, weight of the parenchyma and the tunica albuginea, also aspects such as shape, cavity implantation, relationship with other organs and vascularization. The testicles presented cylindrical shape, with a thin, dense and transparent tunica albuginea, and the vascularization was accomplished by the testicular artery that ramifies from the cranial rectal artery. In the samples from December 2006 and May 2007, the media from the macroscopic measures of the right testicles were volume 58.7 and 14.7 ml, length 9.87 and 3.5 cm, width 2.4 and 0.6 cm, thickness 2.4 and 0.5 cm, circumference 8.0 and 2.3 cm, parenchyma weight 27.6 and 6.1 g and tunica albuginea weight 1.0 and 0.3 g, P < 0.05, respectively. The epididymides, the media from macroscopic measures December 2006 and May 2007 were volume 7.7 and 3.0 ml, length 5.8 and 1.3 cm, width 0.7 and 0.3 cm, thickness 0.6 and 0.3 cm, circumference 2.5 and 1.2 cm, tissue weight 6.4 and 2.8 g and capsule weight 0.4 and 0.1 g, P < 0.05, respectively. Some measures from the right testicle and epididymis were superior to measures taken from the left ones ( P < 0.05), but these were not characterizing asymmetry. The morphometric parameters observed during November 2005 remained on an intermediate situation ( P < 0.05); however, they were quantitatively closer to the means of December 2006, which may characterize it as a potential transition period between repose and sexual activity. Morphologically, the testicles and epididymides of greater rhea have common points with other researched birds; however, differences were observed. The testicles and epididymides of the Rhea americana are influenced by the environment, presenting reproductive activity season (November-December) during late spring, early summer and sexual repose season (May) during autumn-winter. The morphometric testicular and epididymal measurements were introduced. The morphometric parameters of testicles and epididymides exhibited differences between winter and spring-summer that could be established like sexual activity season. [ABSTRACT FROM AUTHOR]

The use of common rhea, Rhea americana, as breeding bird requires knowledge of nutritional physiology. It is important the analysis jointly of feed intake, behavior and weight gain. Our objective was to determine and analyze differences in the feed intake, weight gained and behavior of captive subadults and adults male and female rheas during autumn and winter in the Humid Pampas, Argentina. Neither males nor females showed significant seasonal differences in the weights with which they initiated the trials. Daily feed consumption didn't show significant differences neither between seasons nor between sexes. However, we observed differences in weight gain by males between seasons and during the autumn trial, the weight gain was higher for males. Rhea behavior also varied seasonally. Males and females spent more time preening and resting than walking and feeding during autumn, the opposite occurred in winter. The males had a higher tendency towards walking than to feeding, the females showed the opposite in autumn. Analyzing the feed intake, weight gained and the time spent on feeding we hypothesized that males are more efficient for feeding. This analysis allowed us to observe there are nutritional issues that can be explained from a behavioral point of view. [ABSTRACT FROM AUTHOR]

The Greater Rhea is a bird with a high reproductive potential because of its high degree of adaptation to rural environments. It is a polygamous bird found in the south-central region of Brazil. This study aimed to verify the quantity and weight of eggs produced by 60 adult Rhea americana from a farm and to correlate them with the temperature, relative humidity, and rainfall in a Brazilian region at 25° S. One thousand and four eggs from a commercial farm were analyzed during the breeding season of the animals over four years. The egg laying frequencies and average weight of eggs were divided into interval class of ten according to the Sturges ratio. In addition, the data were fitted to a Weibull distribution. Overall, analysis of the years found a 113.7 day reproductive season for Rhea americana , and egg laying took place on 72.6% of days when the minimum average temperature reached 14.8 and the maximum average 20.8 °C. It was concluded that the environmental variables had influenced reproduction; the best conditions for egg laying in this species occurred at a temperature of 17.1 °C, relative humidity of 79.8%, and rainfall of less than 11.3 mm per day. Lower temperatures resulted in better reproductive performance, while higher rainfall and temperatures resulted in decreased egg laying and egg weight. [ABSTRACT FROM AUTHOR]

Cholangiocarcinomas are neoplasms that originate from the bile duct epithelium. The present case described a cholangiocarcinoma in an adult female American Rhea (Rhea Americana araneipes) by means of gross, histopathology and immunohistochemistry. Irregular, firm, multifocal, yellow-white masses, measuring from 0.4 to 6cm in diameter were observed in both liver lobes. At the cut surface, multiple firm nodules filled with connective tissue were present. Microscopically, the neoplasia was composed of small, irregular, gland-like structures of neoplastic cells surrounded by connective tissue. The cells resembled epithelial cells of the hepatic biliary ducts. Neoplastic cells were positive for cytokeratin and negative for vimentin. This is the first report of a malignant fatal neoplasia in an American Rhea. [ABSTRACT FROM AUTHOR]

There are few studies concerning the parasites of rheas. However, parasitism is the major cause of the limited success in captive breeding of these birds. Deletrocephalus dimidiatus, Deletrocephalus cesarpintoi, Paradeletrocephalus minor, and Sicarius uncinipenis are the most prevalent nematode species affecting these birds, but the lesions caused by these parasites have not been previously reported. Four adult rheas were necropsied to determine the presence or absence of gross lesions within the gastrointestinal tract, associated with parasitic infection. Two rheas parasitized by S. uncinipenis had ulcers on the koilin layer or had parasites penetrating this layer, resulting in widespread necrosis and hemorrhagic areas, whereas the 2 nonparasitized birds did not present lesions. The degree of injury was proportional to the parasitic load found in the birds. Thus, high parasitic loads can result in necrosis of the ventriculus, which may contribute to the death of birds, resulting in economic losses in the rural production of these birds. [ABSTRACT FROM AUTHOR]

In recent years, wild populations of Greater Rhea ( Rhea americana) have declined drastically, due mainly to the conversion of grassland into cropland as a result of intensive, specialized agricultural practices. In this study we test the potential stressful effects of agricultural activities on this ratite by assessing their adrenocortical response. Specifically, we compared fecal glucocorticoid metabolite (FGM) levels of rheas living in two areas under very different land use: grasslands mainly used for cattle grazing and agro-ecosystems intensively used for crop production. Groups of rheas were observed during 45-50 min from a distance of approximately 1 km to avoid any potential disturbance. Therefore, no matching of each fecal sample with a particular sex or individual within the group was possible. Radioimmunoassay of fecal samples from 269 individuals indicated no significant differences in mean concentrations of FGM from the two habitats sampled. In the agro-ecosystem we found no overall effect of agricultural practices on the birds' FGM levels. However, during the dry season FGM concentrations were significantly higher, which may represent a stress response to the low availability of food in the post-harvesting season. In contrast, no increase in FGM levels was registered during the dry season in the grassland, where food was available throughout the year. In this environment the highest increases in FGM levels coincided with the reproductive period, likely due to the frequent agonist encounters between males at this time of the year. Our findings, therefore, suggest that the agricultural practices have to be viewed as chronic environmental stressors for Greater Rhea populations living under such conditions. The present results support earlier research showing detrimental impacts of agricultural activities on this species, which inhabits the most productive regions of South America. [ABSTRACT FROM AUTHOR]

Background: Chemical restraint is of great importance in the clinical practice of wildlife animals. In such, interspecific allometric scaling proposes pharmacological doses to a wide range of species, based on previously known doses for domestic animals and the target animal’s body mass. The objective was to compare chemical restraint responses in the greater rhea (Rhea americana) with conventional doses of tiletamine/zolazepam, found in the literature for the species, and with doses calculated through interspecific allometric scaling extrapolation. From the Federal University of Piauí, six adult greater rheas (Rhea americana), three males and three females, were randomly selected to be subjects in this research. All six animals were submitted to two chemical restraint protocols with tiletamine and zolazepam, per intramuscular injection in the hind limb. The first protocol was composed of doses found on the literature for the species, while the second protocol used doses calculated by interspecific allometric scaling, with the domestic dog as model animal. Heart and respiratory rates, body temperature, eyelid reflex, digital pinch and metatarsal reflex were registered along with latency and ambulation times. Results: The use of interspecific allometric scaling for chemical restraint with the combination tiletamine and zolazepam showed satisfying results, with great similarity to results obtained with conventional doses in Greater rheas. Conclusions: Literature on chemical restraint and use of tiletamine and zolazepam in rheas is scarce. Chemical restraint is of extreme importance on these animals, due to their aggressive nature and low level of domesticity. This research may further establish the interspecific allometric scaling method as a viable tool for the veterinary physician in formulating anesthetic and chemical restraint protocols for wildlife animals. [ABSTRACT FROM AUTHOR]

Seasonal rhythm in sex hormones has been extensively studied in birds, as well as its relationship with the type of mating system. The Greater Rhea (Rhea americana), a South American ratite species, reproduces seasonally and has a complex mating system: female-defense polygyny and sequential polyandry. The present study aimed at analyzing the endocrine basis of reproduction in this species and its relationship with its mating system. We used HPLC and electrochemiluminescence techniques to identify and measure plasma testosterone and estradiol levels. Annual oscillations in sex hormones, testosterone and estradiol, in adult males and females were observed. Lower levels of these hormones were exhibited during the non reproductive season (February to July), whereas their maximum values were reached in September for males and November-December for females. These fluctuations reflect the seasonal changes in gonadal function. By contrast, no significant sex hormones oscillations were observed in juvenile males and females (negative control of seasonal changes). Greater rheas maintain high testosterone and estradiol levels throughout the reproductive period. The high testosterone levels during incubation and chick rearing did not inhibit parental behavior in males, which appears not to conform to the “Challenge Hypothesis”. In females, the high estradiol levels throughout the reproductive season would be needed to sustain their long egg-laying period. [ABSTRACT FROM AUTHOR]

An individual-based model for estimating the energetic costs in Rhea americana was developed considering their sexual and seasonal differences in the behavioral activities. The model includes as variables the individual's characteristics, as well as corporal weight, the time spent on different activities, and the cost associated with each activity. We estimated the daily energetic demand of an adult rhea based on the activities individuals normally develop during postreproductive, nonreproductive, and reproductive seasons, differentiating between sexes. The time spent in each activity for one given animal was calculated from field observations of individuals and the estimations of energetic costs for each activity were obtained from specialized literature. The model built varied between sexes because males and females have different reproductive costs. Both models have the same general formulation but they differ in the cost associated with reproduction. In Greater Rheas, while males assume all of the incubation, the females only lay eggs communally in a single nest. Also the possibility that the individual reproduces or not was considered. The model does not allow to determine whether the energetic costs associated with the breeding are the reason why few individuals try to reproduce but it indicates that there is a clear difference in the daily energetic costs of individuals which reproduce and those which do not reproduce. Other activities associated with parental care posthatching, not taken into account here, would increase these differences, and would explain the low number of breeding attempts observed at wild. [ABSTRACT FROM AUTHOR]

Abstract: Few data exist on the parasites of ratites, especially from regions within their natural range. It is only recently that extensive studies on the parasites of ostriches (Struthio camelus) have been published, mainly from European countries where commercial farming has expanded. Two species of ratites are native in South America: the lesser rhea also known as Darwin''s rhea (Rhea pennata) and the greater rhea (Rhea americana). Both species are considered near threatened by the IUCN and are included in the CITES’ Appendices I and II, respectively. Parasitological studies have conservation implications, as they allow us to assess the risk of transmission of pathogens from farmed ratites to wild populations. In this study 92 faecal samples from greater rheas and 55 faecal samples from lesser rheas from different localities in Argentine were analyzed to determine their gastrointestinal parasites. In greater rheas the protozoa (Balantidium coli-like and Entamoeba spp.) and helminths (Fasciola hepatica and Deletrocephalus spp.). The protozoa had not previously been cited as parasites of greater rheas in South America. Cysts and/or trophozoites of B. coli-like were found in 16.3% of the samples, while the prevalence of the remaining parasites was below 10%. Lesser rheas harbored the protozoa B. coli-like, Entamoeba spp. and Chilomastix spp. as well as F. hepatica and nematode eggs and larvae. B. coli-like cysts were found in 20.0% of the samples, while the prevalence of the other parasites remained below 5%. Some of them had not been cited as infecting lesser rheas yet. [Copyright &y& Elsevier]

Animal transport is an indispensable practice in species that need to be moved for management or commercial purposes. However, transport may have negative effects on individuals' welfare. The aims of the present work were to determine if the behavioral responses of adult Greater Rheas (Rhea americana) bred in captivity are sensitive to short-term transport and if males and females differ in their posttransport behavioral activity and recovery. Eight males and 8 females were placed in individual pens and allowed 6 d to habituate (d 1 to 6) before transport procedure. On the transport day (d 7), half of the birds (4 males and 4 females) were randomly assigned to a transport group that was captured and handled to be placed into the crates, exposed to a 30-min transport stressor, and immediately returned to their pens. Four transports with 1 different male and female each time were performed. The other half remained undisturbed and were used as controls. Behavior of all individuals was video-recorded during habituation days, after transport on d 7, and on the 2 following days (d 8 and 9) to evaluate pre-and posttransport behavioral activity for 2 h per day. No significant behavioral changes were observed during the last 2 d of the habituation period (d 5 and 6), suggesting that Greater Rheas were adapted to the housing conditions before transport. After transportation, several behaviors were affected: transported males and females showed null resting, transported females also showed reduced preening and increased vigilance (P < 0.05), whereas transported males showed increased drinking (P < 0.05) compared with their respective control groups. The results suggest that behavioral responses of captivebred Greater Rheas are sensitive to short-term transport (which includes handling) and that males and females differ in their posttransport behavioral activity, recovering their overall basal levels on the third day posttransportation. [ABSTRACT FROM AUTHOR]

Using slit-lamp biomicroscopy, conjunctival biopsy, and morphological identification, a flock of four Greater rheas ( Rhea americana) in Arizona were diagnosed with conjunctivitis secondary to Philophthalmus gralli ( P. gralli) infection. Aquatic snails from the exhibit's water source were identified as Melanoides tuberculatus, a known vector for P. gralli. Comparison of partial sequences of DNA regions from P. gralli adults removed from the rheas and metacercariae from the aquatic snails demonstrated a 100% match, confirming the source of infection. The flock was divided into two treatment groups: the most severely affected rheas received both manual removal of trematodes and praziquantel 1% ointment OU q12 h and the least severely affected rheas were only given praziquantel 1% ointment OU q12 h. The rheas were permanently relocated away from the infected water source and aquatic snails. Initial resolution was seen at 17 weeks in the most severely affected rhea, which had 675 adult P. gralli removed and topical praziquantel. The two rheas that only received topical praziquantel showed resolution within 3 and 15 weeks. Current recommendations for treating P. gralli include: manual removal of trematodes, topical praziquantel 1% ointment, and relocation away from infected water sources and aquatic snails. [ABSTRACT FROM AUTHOR]

Background: The rhea (Rhea americana) is a Brazilian wild bird that produce meat, leather and feathers of excellent quality. Rhea production has been increasing every day in Brazil due to many favorable conditions for breeding and there are also large native populations in various regions of the country. The incidence of parasites is a limiting factor when raising many animals, and rheas are not an exception. The occurrence of Cryptosporidium spp in captive rheas in a Brazilian zoo and Spain was described. However, little is known about cryptosporidiosis in rhea, which makes the need for further studies. Thus, this study aimed to detect Cryptosporidium parvum in rheas from the South of Brazil. Case: This study evaluated two properties located in Southern Brazil. Property A was located in Rio Rufino, Santa Catarina State, Brazil and it had 40 rheas for commercial purposes. Property B was located in Santa Maria, a small town in Rio Grande do Sul State, Brazil and it had 10 rheas. Fresh fecal samples were collected and kept refrigerated from adult birds (n = 4) and chicks (n = 2) from property A, and chicks (n = 3) of three months of age from property B. Samples were analyzed by the method of direct examination, followed by centrifugal flotation with zinc sulfate. Only the centrifugal flotation technique allowed the observation of Cryptosporidium spp. oocysts in three adults and one chick. Fecal samples were stored in ethanol and analyzed by PCR for C. parvum, all being positive for this protozoan. Feces contaminated by C. parvum oocysts from one young rhea was used to inoculate two mice orally (BALB/c), previously confirmed protozoan free by faecal examination and PCR. Feces from inoculated mice were collected on days 1, 3 e 5 post-inoculation for analysis by the centrifugal flotation technique. After five days of inoculation all mice presented diarrhea and high numbers of oocysts of protozoan in their feces. Discussion: Cryptosporidiosis can evolve into severe diarrhea, followed by abdominal cramps, anorexia, vomit- ing, dehydration, nausea and fever in different animals. However the incubation period of this disease in rheas is unknown because this is only the third report of cryptosporidiosis in this wild bird. The Cryptosporidium spp. is an obligate parasite of vertebrates, and its colonization occurs at the periphery of the intestinal cells of the host and it may cause atrophy of these structures and enteritis, but these findings have not been described in rheas yet. The species of Cryptosporidium that are mainly reported in birds are Cryptosporidium meleagridis, Cryptosporidium baileyi and Cryptosporidium galli. In our study, the molecular analysis was performed in order to identify the protozoan, being detected the C. parvum, a zoonotic agent reported in several mammals. The rhea is wild birds with habits similar to ostriches. Already, in studies have reported the occurrence of Cryptosporidium in ostriches; however the species identified were different from that described in this study. Based on these results, we conclude that rhea may be parasitized by C. parvum, an important zoonotic parasite. Prevalence studies should be conducted in this area to estimate the role and impact of rhea as reservoirs and disseminators of this zoonotic parasite. [ABSTRACT FROM AUTHOR]

The effect of transport stress on blood corticosterone levels in captive Greater Rheas was investigated. Twelve adult individuals (7 males; 5 fe-males) were loaded in pairs inside wooden crates and transported along a paved road for 30 min. Blood sam-ples were taken before the individuals were introduced into the crate (baseline value) and immediately after they were unloaded (30 min after capture). To assess whether corticosterone levels were affected by the blood sampling procedure per se, another 6 (nontransport) control birds (3 males; 3 females) were also captured and sampled at the same times as their transported counterparts. Plasma corticosterone concentrations were measured using a commercially available corticos-terone 125I radio-immunoassay kit. Baseline corticoste-rone levels were similar in the control and transported birds (9.0 ± 1.6 and 10.4 ± 0.8 ng/mL, respective-ly). Transportation induced a highly significant (P < 0.001), more than 40-fold increase in the corticosterone levels (433.6 ± 35.4 ng/mL) that was about 5 times higher (P < 0.001) than in their nontransported coun-terparts (88.4 ± 14.8 ng/mL). The present findings suggest that Greater Rhea is a species highly sensitive to stressful manipulations. Both blood sampling and transportation induced highly significant adrenocorti-cal responses. Considering that transportation is one of the unavoidable common practices in the management of Greater Rheas and, as shown in the present study, that it induces a significant 40-fold corticosterone stress response, efforts should focus on helping to generate management transport standards for optimization of the welfare of this ratite. [ABSTRACT FROM AUTHOR]

The article presents information on a study related to Greater Rheas, in which the routine physical examination, medical treatments and surgical procedures in both zoological and farm-raised settings are required to check the possibility of ratites. It informs that the ratite anesthetic events are often dangerous for the handlers of theses birds because these birds use their powerful legs and clawed feet as a defense and physical restraint. It further informs that the anesthetic combination of choice would have low volume and high potency and be reversible, with minimal adverse effects.

A study aimed to determine the infection model that picobirnavirus (PBV) established in birds was conducted in a farm of greater rheas in Córdoba, Argentina. Analysis of stools collected during a longitudinal study involving seven birds provided evidence that PBV is acquired very early in life and establishes a persistent infection in the host, which is characterized by intermingled periods of high, low and silent viral activity. Genomic analysis indicated that the rheas excreted virus with nucleotide sequence identity between 90.5-100 % and that more than one PBV strain with different electropherotype profiles could be involve in the infection. This report provides the first evidence of persistent infection of PBV in birds. The natural history of PBV infection has begun to be understood, and it appears that asymptomatic PBV-infected mammals and birds could persistently excrete the virus in stool samples, contributing to wide circulation of the virus in the environment. [ABSTRACT FROM AUTHOR]

The capacity to recognize and respond to predators can be lost by captive animals. Habituation to humans caused by the captive environment can be transferred to other stimuli, such as predators, a situation that conservation biologists wish to avoid. Greater rheas are threatened South American birds, for which there are plans for reintroduction programs in Brazil. The goal of this study was to evaluate the behavioral responses of captive-born greater rheas to different models of predators and nonpredators. Seventeen captive-born greater rheas, divided into four groups, from the Belo Horizonte Zoo, Brazil were studied. Three predator and three nonpredator models were presented to the birds and their behavioral responses recorded. Predators versus nonpredator models and the behavior of rheas in three experimental phases (baseline, models, and postmodels) were analyzed. Captive-born greater rheas modified their behaviors in the presence of both predator/nonpredator models, increasing alert and wary behaviors (alert, observing, and pacing behaviors: P < 0.01), showing some degree of antipredator behavior persistence, but they were unable to discriminate between predator and nonpredator models (all behaviors: P > 0.05). In conclusion, antipredator training should be implemented to develop the expression of this behavior before reintroductions are attempted. [ABSTRACT FROM AUTHOR]

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The tongue body of Rhea americana is triangular and partially pigmented with each caudo-lateral margin displaying a round, sub-divided lingual papilla. The tongue root is a smooth, non-pigmented tract of mucosa. The tongue body is supported by the paraglossum and distal half of the rostral projection of the basihyal (RPB), and the tongue root by the proximal half of the RPB, body of the basihyal and proximal ceratobranchials. An urohyal is absent; however, peculiar to R. americana, the caudal margin of the cricoid body displays a median projection, which may represent the remnant of the urohyal incorporated into the cricoid. The laryngeal mound is less elevated, the arytenoid cartilages are smaller than in other ratites, and the caudal margin displays pharyngeal papillae that vary in shape and number. The unique morphology of the lingual skeleton and its positioning within the tongue of R. americana, the rostral insertion of the M. ceratoglossus, the absence of the urohyal (enhanced ventroflexion) and the caudal positioning and mobile attachment of the ensheathed basihyal to the paraglossum would appear to allow independent movement of the tongue body relative to the hyobranchial apparatus. Additionally, the deeply indented base and rostral oval opening in the paraglossum limits the length of cartilage present in the midline of the tongue body. This may allow the tongue the necessary flexibility for the lingual papillae to clean the choana. The cleaning action of the tongue would occur simultaneously with the previously described role of this organ and associated structures during feeding. Thus, the so-called reduced, ancestral tongue of R. americana may be structurally and functionally more complex than previously believed. [ABSTRACT FROM AUTHOR]

Abstract: Histochemical and structural characteristics were investigated in Gastrocnemius pars interna (GN) and Iliofiburalis (IF) limb muscles of Rhea americana. The average myofibre area cross-section was greater in GN than IF muscle (p <0.001), whereas the fibre density per section was higher in IF than GN muscle. The only type of myofibre found in both the rhea limb muscles analysed in this study was fast-twitch oxidative–glycolytic fibres (FOG). Immunolabelling analysis and ultrastructural observation of myofibres confirmed the contractile and metabolic characteristics of rhea myofibres, revealing the absolute fast isoform of myosin heavy chain and the abundance of glycogen and mitochondria inside the cells, mainly in IF muscle. These findings converged with previous results on the biochemical and physicochemical characteristics of rhea meat to provide further evidence that myofibre composition substantially influences the oxidative reactions of the muscle and therefore the meat quality, but more in-depth examination is needed to establish the links between myofibre characteristics, myofibre glycogen concentration and meat stability during storage. [Copyright &y& Elsevier]

Visitors can affect and reduce the welfare of nonhuman animals. The Belo Horizonte Zoo, Brazil, had a group of greater rheas intended for reintroduction to the wild. Because this group received public visitation, evaluating its effect on the birds' behavior and welfare was important. The study conducted 60 hr of behavioral observations: 30 with, and 30 without, visitors in front of the birds' enclosure. The study, conducted April–December 2009, collected data using scan sampling with instantaneous recording of behavior every minute. The study collected data on public behavior, visitor density, and time spent observing the birds. More than 4,000 persons visited the birds' enclosure: 9.86 s average time spent. Public behaviors most expressed were walking-watching-talking and stopped-watching-talking; visitors or not, greater rheas' most expressed behaviors (inversed between treatments) were foraging and walking alert; defecating/urinating and other behaviors differed statistically between treatments. Walking alert was most expressed in the presence of visitors; defecating/urinating and other behaviors were most expressed in their absence. Greater rheas seemed to habituate to visitors. Birds' behaviors differed little in visitors' presence or absence. [ABSTRACT FROM AUTHOR]