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Purpose To carry out a descriptive investigation of the capybara (Hydrochaeris hydrochaeris) eye and to perform selected ophthalmic diagnostic tests with the aim of establishing normal physiological reference values for this species. Method A total of 22 healthy, capybaras were used to test most of the parameters in this investigation. Ages varied from 2 to 4 years of age. Selected diagnostic ocular tests were performed including Schirmer tear test, tonometry using an applanation tonometer (Tonopen®), central corneal thickness using an ultrasonic pachymeter (Sonomed, Micropach®, Model 200P +), axial globe length and culture of the normal conjunctival bacterial flora. Results and discussion Capybara's normal ocular features include: dorsal and ventral puncta, vestigial third eyelid, true cilia only at the upper eyelid margins. The bulbar conjunctiva is noticeably densely pigmented with a brown to bronze color. The capybara's pupil is oval in shape and vertical in position No tapetum lucidum is present in this species and the retinal blood vessels are almost absent. Results for selected ocular diagnostic tests investigated were: Intraocular pressure: 18.4 ± 3.8 mmHg; Schirmer tear test: 14.9 ± 5.1 mm/min; Central corneal thickness: 0.46 ± 0.03 mm; Axial globe length: 22.20 ± 1.71 mm. No statistically significant differences between ages or genders were found for any of the results. Corynebacterium sp., Micrococcus sp., Bacillus sp. and Staphylococcus sp. were isolated from healthy conjunctiva, suggesting they are normal constituents of the conjunctival flora of the capybara eye. The corneal epithelium of the capybara possesses a thin and discrete Bowman's layer. Results and parameters obtained in this investigation exposed unique anatomic features of the capybara eye and will help veterinary ophthalmologists to more accurately diagnose discrete or unusual pathological changes of the capybara eye. Furthermore, corneal thickness and axial length of the capybara are similar to that of human beings, revealing that the world's largest living rodent might be an excellent biological model for ophthalmic studies.

The aim of this work is to describe an epidemiological model for a capybara (Hydrochaeris hydrochaeris) population. The model considers a tabanid ("mutuca") population (Diptera: tabanidae), as a vector for the disease called "mal de las caderas" in Estero del Ibera, Corrientes, Argentina. The study of this problem has ecological and economical importance since the meat and the hide of the capybara can be an exploitation resource. At first, a threshold value is determined as a function of the model parameters, obtaining a critical carrying capacity which determines the disease propagation or eradication. Then as the carrying capacity condition for the disease existence is satisfied, the existence of traveling wave solution is studied. Independent speeds are considered for the susceptible capybaras, the noninfected insect, and the disease. The speed of propagation for this model is obtained as function of model parameters followed by a discussion of strategies for controlling the spread of the disease.

Capybara (Hydrochaeris hydrochaeris ) is the largest living rodent, widely distributed in South America, with a considerable potential as an economic resource. There are large populations in the region of Esteros del Ibera that could be exploited in a sustainable manner and contribute positively to the development of the region. Such exploitation requires to be done responsibly and following a specially designed management plan. In the particular case of wildlife management, a sustainable exploitation of a given species requires knowledge of its dynamics, its density in the area, and its vital rates, as well as understanding how the natural environment will respond to the proposed manipulation. It is also important to determine which environmental variables lead the population dynamics in each region. A mathematical model is a very convenient tool for analyzing possible strategies. This work presents a matrix population model structured in five stages. Sensitivity and elasticity analyses of the model provide an understanding of the effects of differentiated class-dependent survival and growth probabilities on the life cycle. A harvest term has been included in the model with the purpose of evaluating the sustainability of a given exploitation scenario or comparing different harvest strategies. The different strategies depend on the exploitation pattern, the exploitation intensity, and the season in which the harvest takes place. The purpose is to formulate a simple tool that can be understood by a manager without specific training. Hence, the software interface was specially designed for a user with elementary knowledge of vital parameters of the species. © 2005 Elsevier B.V. All rights reserved.

Entre os dias 27 de agosto e 24 de setembro de 2001 estudou-se o comportamento de capivaras jovens em semiconfinamento no Distrito de Floriano, Estado do Paraná. Um grupo de nove animais foi alojado em um piquete com acesso a banhos de imersão durante todo o experimento, enquanto o outro permaneceu sem acesso a tal recurso. Os dados climáticos foram registrados a cada hora. Não foram verificadas diferenças no comportamento entre os tratamentos, sugerindo a possibilidade de piquetes sem piscina para capivaras em crescimento e em regime de semiconfinamento. Em casos de insuficiência de sombra para a proteção da radiação solar, o recurso “piscina” tem grande importância no alívio do estresse calórico. Os comedouros dispostos de forma linear foram os maiores estressores no manejo dos animais. Pela escassez de pesquisas com Hydrochaeris hydrochaeris em regime de produção, as discussões deste trabalho tiveram como comparativos pesquisas realizadas com animais em habitat naturalThe young semi-confined capibaras behavior was studied from 27th August to 24th September, in 2001, in Floriano - Paraná State, Brazil. A group of nine capibaras was placed in confinement in a picket to have dips during all the experience, while another group of animals had no access to such dips. Weather conditions were registered every hour. There was no difference regarding the animals’ behavior during the treatment, which suggests the possibility of pickets with no pools for grown-up semi-confined capibaras. When there is no shadow against sun irradiation, the ‘pool’ has great importance for the relief of caloric stress. The feeding places, which were arranged linearly, caused great stress on the animals’ handling. This work was based on research with animals in their natural habitat due to the scarcity of research concerning the breeding of Hydrochaeris hydrochaeris

The aim of this work was to evaluate the effects of the factors sex and different slaughter weight groups (30-40, 40-50, 50-60kg) in the pH decline, ultimate pH, colour, water holding capacity (WHC), cooking loss (CL) and shear force (SF) of capybara (Hydrochaeris hydrochaeris) meat. Samples were constituted of longissimus dorsi (LD) muscle of 28 capybaras (16 males and 12 females) from the same farm. There were no effect of the factors sex and slaughter weight groups on the pH values at 2h (6.29), 5h (6.29), 8h (6.25) and 24h (6.01) post mortem; on colour values (CIE LAB System) for brightness (34.28), redness (10.74) and yellowness (1.74); WHC (0.47), CL (32.27%) and SF (5.20kgf/g). Comparing to livestock species, capybara meat had a high ultimate pH value, low values of brightness and high values of redness, looking like bovine and ovine meats (red meats); WHC and CL inside limits considered normal; and SF considered soft.

The present study analysed the response of adult female capybaras (Hydrochaeris hydrochaeris) to different dietary supplementation in relation to litter size per parturition and oestradiol secretion profile during pregnancy and the oestrous cycle. All four experimental groups received 'camerum' grass (Pennisetum purpureum) and water ad libitum and three of the groups were also fed a protein, lipid or protein and lipid supplement. Litter size per parturition did not show any significant difference among treatment groups, but was significantly higher (P < 0.05) than in the control group. There was no significant difference in oestradiol concentrations among treatments and the control group, during each phase of the oestrous cycle or during gestation. The average oestradiol concentrations in dioestrous, oestrous and metoestrous phases were not significantly different from each other, but were significantly lower (P < 0.05) than the average oestradiol concentration in the pro-oestrous phase. In addition, average oestradiol concentrations increased after the second gestation month, but were significantly higher (P < 0.05) only after the fourth gestation month, achieving maximum value by the end of gestation. Dietary supplementation had no significant effect on hormonal concentrations during the oestrous cycle and gestational period. However, an increase in litter size per parturition was observed among female capybaras that received dietary supplementation.

Les niches trophiques du cabiai et du betail domestique ont ete etudiees dans le centre de 1'« Entre Rios » (entre les fleuves Parana et Uruguay), en Argentine. C'est par l'analyse micro-histologique de feces collectees entre 1990 et 1992 qu'on a pu determiner la composition du regime alimentaire de ces animaux au cours des saisons? Vingt-six especes de plantes fourrageres ont ete identifiees dans l'alimentation du cabiai et des bovins, et 23 dans celle des ovins. C'est au printemps que l'on constate le maximum de diversite alimentaire pour les trois especes; le minimum est en ete pour les cabiai et les moutons, et en hiver pour les bovins. La niche trophique du mouton est plus large que celle des bovins et du cabiai. En ete les moutons et le cabiai ont ete plus selectifs que les bovins, mais les vaches etaient plus selectives en hiver. La superposition des niches trophiques varie de 77,8 % entre bovins et ovins en automne a 51,8 % entre le cabiai et les ovins en ete. Les pourcentages de superposition des regimes (> 50 %) suggerent qu'il existe une competition alimentaire entre les trois especes. Les resultats de cette etude montrent que l'heterogeneite de l'espace et du temps combinee avec la densite des animaux,., peut avoir un impact considerable sur les caracteristiques de leurs niches trophiques. L'analyse de celles-ci doit cependant etre completee par l'etude des conditions d'utilisation de l'habitat et de la segregation entre les herbivores en question si l'on souhaite etablir des conclusions valables sur l'existence d'une competition interspecifique.

Damage caused by capybaras in agroecossystems in Brazil has been frequently observed. The objective of this study was to describe and quantify the actual damage caused by capybaras in a corn field, aiming to get basic information on how, how much, and where these damage occur. Systematic sampling indicated that 26% of the planted area were damaged by capybaras, and the highest percentage of damage occurred on the border of the corn field (t=4.5698, p=0.0001). Damage in areas adjacent to a forest fragment was significantly higher (t=13.6198, p=0.0001), suggesting that the strategy of area utilization for feeding was related to the proximity of the resources "forest" and "water". Avoiding corn plantation in areas adjacent to forest fragments used by capybaras and, when possible, controlling capybara population may lead to a reduction of damage occurrence in agroecossystems. Danos causados por capivaras em culturas agrícolas no Brasil têm sido freqüentemente reportados. O objetivo deste estudo foi descrever e quantificar os danos causados por capivaras em um campo de milho, visando obter informações básicas de quanto, como e onde esse dano ocorre. Através da amostragem sistemática obteve-se que 26% da área plantada foi danificada por capivaras, sendo que a maior porcentagem dos danos localizou-se nas bordas do campo de milho (t=4.5698, p=0.0001). O dano em áreas adjacentes ao fragmento de mata foi significativamente maior do que no restante do terreno (t=13.6198, p=0.0001), sugerindo que a estratégia de utilização da área de alimentação pela capivara relaciona-se com o fator proximidade dos recursos "floresta" e "água". Evitar o plantio de milho em áreas adjacentes a fragmentos florestais utilizados por capivaras e, quando possível adotar práticas de controle populacional, podem significar a redução da ocorrência de danos causados aos agroecossistemas.

The digestive system of the capybara has been investigated because of its coprofagia habits, important for their absorptive activity. These species present differences in terms of gastrointestinal morphological characters when compared with other rodents. Macroscopiclly, the stomach of the capybara is constituted of the following parts: cardiac, pyloric, body, fundic and gastric diverticulum. It presents two curvatures, one big and another small. Externally, the presence of gastric bands (tenias) is observed. With regards to the volumetric view, the gastric capacity varies from 850 to 2010 ml, with an average of 1498.57 ml. So, the stomach of this animal can be classified as a simple stomach, in the format of a curved sack and similar to an inverted letter 'J'. The gastric mucous membrane presents a surface filled by numerous tortuous gastric folds and longitudinally distributed along all its extension. The mucous tunic also possesses recesses located among the successive gastric folds, which were denoted as gastric parts with numerous openings described as gastric pits. In the cardiac part, a glandular epithelium with cardiac glands is noticed containing a lot of parietal and mucous neck cells. The fundic part, body and gastric diverticulum contain proper gastric glands with main, parietal and mucous neck cells. Finally, the pyloric part has pyloric glands with two cellular types, mucous neck and parietal cells.

Fil: Santa Cruz, A. C. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: Comolli, Javier Alejandro. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: Ortíz, Joaquín. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: González, Jorge, A. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: González, Alfredo Oscar. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. El objetivo del trabajo fue verificar la existencia de variaciones morfométricas de Trypanosoma evansi en Hydrochaeris hydrochaeris criados en cautiverio en Chaco, Argentina. Para ello se efectuaron mediciones de variables biométricas de 52 ejemplares de T. evansi provenientes de carpinchos. Se reconocieron dos variaciones morfométricas del parásito, delgadas y rechonchas. Las dimensiones de ambas formas se compararon con los resultados obtenidos en T. evansi de carpinchos del amazonas peruano. Los resultados revelaron diferencias significativas en todas las variables sometidas a estudio (p

The capybara is a species that is bred for its meat in Brazil due to its elevated reproductive potential and because, being a herbivore, it does not compete directly with humans. Controversies exist regarding cecotrophy behavior in this animal. Cecotrophy is observed in lagomorphs and certain rodents and consists of the ingestion of a specific type of excrement produced in the cecum. Six adult capybaras were placed in individual pens and observed for 96 serial hours. During this period a behavioral pattern that we believe consisted of cecotrophy was observed 243 times. Animals sat on their hind limbs, stretched either limb out, bent over driving their heads in the direction of the anus and licked a pasty material that differed from normal oval-shaped feces. This behavior was observed between 10 h:48 min and 11 h:44 min after ingestion of food. When food was supplied at 5:00 p.m., 73% of the cecotrophy acts occurred between 6:00 and 12:00 a.m. while 27% between midnight and 6:00 a.m. The observation of cecotrophy behavior in capybaras is important because it suggests that maintenance expenses with protein supplements for this specie in captivity can be reduced.

The molecular variants of Gonadotropin releasing hormone (GnRH) in brain extracts of the eutherian mammal Hydrochaeris hydrochaeris (Mammalia, Rodentia) were characterized. An indirect method combining reverse-phase high-performance liquid chromatography (RP-HPLC) and radioimmunoassay (RIA) with different antisera was used. Two different forebrain regions (olfactory bulbs and preoptic-hypothalamic region) were analyzed. Characterization of RP-HPLC fractions from preoptic-hypothalamic extracts with three different RIA systems revealed two immunoreactive GnRH (ir-GnRH) peaks coeluting with mammalian GnRH (mGnRH) and salmon GnRH (sGnRH) synthetic standards. These results were additionally supported by serial dilution studies with specific antisera. Similar results were obtained from olfactory bulb extracts with the same methodology. However, a third ir-GnRH peak in a similar position to that of chicken GnRH II (cIIGnRH) synthetic standard was revealed. As far as we know, this is the first report showing chromatographic and immunological evidences for the presence of a second GnRH variant in the forebrain of an eutherian mammal.

Les habitudes alimentaires des cabiais et du betail vivant dans la region non insulaire du bas delta du Parana ont ete etudiees. De plus, des echantillons de ragondins ont egalement ete etudies, egalement par analyse microhistologique des feces. Des echantillons de feces ont ete collectes saisonnierement pendant 2 ans, entre 1991 et 1993. Les resultats ont montre que les Poaceae etaient le principal groupe consomme tout au long de l'annee, a la fois par les cabiais et le betail, a l'exception de l'hiver, ou ce dernier consommait une plus grande proportion de Cyperaceae. Chez ces trois mammiferes herbivores, un petit nombre d'items constituaient l'essentiel du regime alimentaire. Cinq items (Cynodon dactylon, Panicum grumosum, Luzioloa peruviana, Zizaniopsis bonariensis et Eleocharis spp.) representaient plus de 60 % du regime du cabiai et du betail en toutes saisons. Un schema d'alimentation similaire a ete trouve pour ces deux herbivores pendant les deux annees, sauf en ete ou la composition du regime etait differente. Cela a egalement ete le cas lors de la comparaison des regimes d'hiver entre ces deux herbivores et le ragondin. A l'exception de l'ete, les largeurs des niches trophiques du cabiai et du betail etaient similaires. Ces valeurs indiquent une niche relativement etroite en toute saison, definissant ces especes comme herbivores selectifs. Au contraire, le ragondin peut etre considere comme une espece plus generaliste, bien que montrant un regime plutot moins varie que les autres especes. Les valeurs totales et specifiques de recouvrement des niches trophiques suggerent que pendant la saison critique (hiver), les modes d'alimentation des cabiais et du betail divergeraient, pour compenser la faible disponibilite vegetale. Pendant les autres saisons, l'augmentation de la disponibilite en ressources conduirait a une situation de recouvrement important dans l'utilisation des ressources.

Traditionally, wildlife conservation efforts have concentrated on the establishment of national parks and reserves. Additional strategies are needed if we are to conserve more than a small proportion of the world's natural habitats and their wildlife. One such strategy is the application of wildlife conservation regulations by private land owners on their properties. This paper uses examples of ranches in the seasonally flooded llanos of Venezuela to evaluate if effective wildlife conservation can coexist with sustainable wildlife use and cattle production. Income estimates derived from cattle production data varied among ranches from $US7.1 to $US26.4 per ha, while estimates of potential additional income through regulated capybara Hydrochaeris hydrochaeris and caiman Caiman crocodilus exploitation ranged up to $US7.7 per ha. The economic benefits of capybara and caiman harvests can be realized only by protecting wildlife habitat. Thus, it is suggested that large ranches in the llanos can play a major role in wildlife conservation as well as provide economic gains for those involved. Common denominators for success are: personal involvement of owners, effective patrolling systems, co-operation of neighbouring ranchers in patrolling activities, and ranches being located far from densely populated areas. For the programmes to succeed in the long term, government and conservation agencies will need to give more support to landowners.

To infer possible functions for the low gonadosomatic index and the high proportion of non-spermatogenic tissue of capybara testes, we analysed the relationship between testes mass and the size and ratio of the testes compartments and, indirectly, their activities. We found that the testes mass of the capybara is closely associated with the size of androgen-dependent scent glands and to the proportion of non-spermatogenic tissue in the testis. We further investigated the associations between variables related to dominance and to sexual characters. The results suggest that dominance in capybaras is more associated with androgen-dependent scent glands than with sperm production. We suggest that male capybaras compete for dominance with chemical and visual status signalling.

Parasites play a key role in regulating wildlife population dynamics, but their impact on the host appears to be context-dependent. Evidence indicates that a synergistic interaction between stress, host condition and parasites is implicated in this phenomenon, but more studies are needed to better understand this context-dependency. With the goal to assess the net effect of two types of chronic stress on various host-parasite interactions, we conducted an experiment in capybaras to evaluate the impact of food restriction and physical restraint on the infection intensity of specific gastrointestinal nematodes and coccidia, and how these stressors affected the growth, body condition, and some immuno-physiological parameters. Our hypothesis was that both forms of stress would result in an alteration in the host-parasite interactions, with deteriorated condition and reduced immunological investment leading to high parasite burdens and vice versa. Stressed capybaras had significantly higher coccidia infection intensities; but among individuals that were smaller, those stressed consistently showed lower helminth burdens than controls. Both stress treatments had a marked negative impact on growth and body condition, but concomitantly they had a significant positive effect on some components of the immune system. Our results suggest, on the one hand, that during prolonged periods of stress capybaras preventatively invest in some components of their immunity, such as innate humoural defenses and cells that combat helminths, which could be considered a stress-dependent prophylaxis. On the other hand, stress was found to cause greater infection intensities of protozoans but lower burdens of nematodes, indicating that the relationship between stress, physiological trade-offs and infection depends on the type of parasite in question. Moreover, both findings might be related in a causal way, as one of the immunological parameters enhanced in stressed capybaras is associated with the immune response to control helminths., Centro de Estudios Parasitológicos y de Vectores

Fil: Moriena, R. A. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: Ortíz, M. I. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: Racioppi, Oscar. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: Álvarez, José Dario. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. El propósito del trabajo fue poner en discusión el método coprológico tradicional para determinar la presencia del trematodo Fasciola hepatica en carpinchos (Hydrochaeris hydrochaeris). Para tal fin se analizaron por coprología 164 muestras de materia fecal hallándose 21 casos (12,8%) positivos (presencia de huevos compatibles con F. hepatica). Sin embargo, huevos obtenidos directamente del útero por disección de los parásitos del carpincho F. hepatica y Taxorchis schistocotyle (de localización hepática e intestinal respectivamente), fueron indistinguibles entre sí por su similitud morfológica y dimensiones. Por tal motivo se considera que las tasas de prevalencia de fasciolosis obtenidas en carpinchos por coprología son dudosas por no discriminar el tipo de huevo. The purpose of this study is to present the fallibility of the coprologic standard method to determine the presence of the trematode Fasciola hepatica in capybara (Hydrochaeris hydrochaeris). For this purpose, 164 samples were analyzed by coprology and a total of 21 cases (12.8%) were positives, but the eggs found were consistent with the morphology and size of both F. hepatica and Taxorchis schistocotyle, fluke parasites of this rodent, with localization in liver and intestine, respectively. For both types of eggs it was no possible to make morphological differentiation when considering size and shape. As a conclusion, fasciolosis prevalence rates obtained from results using the coprology standard method in capybaras may be considered as doubtful, as the technique does not allow differentiating between F. hepatica and T. schistocotyle eggs.

In order to evaluate the hind limbs of caviomorph rodents a descriptive analysis of the Cuniculus paca (Linnaeus, 1766) and Hydrochoerus hydrochaeris (Linnaeus, 1766) was performed using anatomical specimens, radiography, computed tomography (CT) and full-coloured prototype models to generate bone anatomy data. The appendicular skeleton of the two largest rodents of Neotropical America was compared with the previously reported anatomical features of Rattus norvegicus (Berkenhout, 1769) and domestic Cavia porcellus (Linnaeus, 1758). The structures were analyzed macroscopically and particular findings of each species reported. Features including the presence of articular fibular projection and lunulae were observed in the stifle joint of all rodents. Imaging aided in anatomical description and, specifically in the identification of bone structures in Cuniculus paca and Hydrochoerus hydrochaeris. The imaging findings were correlated with the anatomical structures observed. The data may be used in future studies comparing these animals to other rodents and mammalian species.

Abstract. Capybaras, Hydrochaeris hydrochaeris, live in groups of varying size averaging 10 adults of both sexes. Vigilant behaviour was studied in capybaras under natural conditions, using focal-animal sampling on individual females, dominant males and subordinate males from groups of different sizes. There was a significant negative correlation between group size and individual alert rate, and a positive correlation with total group alert rate. Although the reduction in individual rates of vigilance levelled off at group sizes of 9-10, total alert rate continued to increase. The behaviour of the females accounted for most of the variation in individual alert rate and the behaviour of subordinate males accounted for most of the variation in total alert rate. These results suggest that females benefit the most from being in larger groups due to reduced vigilance required, while subordinate males 'pay' for their group membership by the vigilance they perform.

The prevalence of Mal de Cadeiras--Portuguese for Trypanosoma (T.) evansi infections in horses--as well as the prevalence of T.evansi infections in cattle, dogs and free-ranging capybaras (Hydrochaeris hydrochaeris) was investigated in Pantanal de Poconé (Mato Grosso, Brazil). In 0.3, 8.6 and 8.0% of the horses, dogs and capybaras, respectively, infection was detected using standard parasitological methods. A seroprevalence of 4.1, 2.3, 7.1 and 22.0% was found in horses, cattle, dogs and capybaras, respectively, using an enzyme-linked immunosorbent assay for the detection of T.evansi antigen (Ag-ELISA), whereas 9.6, 4.2, 18.6 and 14.0% of the animals investigated were reactive in a T.evansi antibody (Ab-) ELISA. Positive ELISA results ('high responders') were identified using computer-assisted mixture analysis (C.A.MAN). Agglutinating antibodies were detected by the T.evansi card agglutination test for trypanosomiasis (CATT/T.evansi) in 14.6%, 1.3%, 15.7% and 22.0% of the horses, cattle, dogs and capybaras, respectively. A moderate but significant (kappa test; p0.05) agreement beyond chance level was observed between Ab-ELISA and CATT results but generally not between antibody and antigen detection tests. Therefore, in an attempt to maximize the information yield of the three serodiagnostic tests, their results were numerically scored (negative = 0, intermediate = 1, positive = 2) and added up to a total score (TS) which was considered indicative for infection when TSor = 4 (results of the Ag-ELISA received double weight). Estimates of seroprevalence according to TS were 13.2, 4.7, 30.0 and 24.0% for horses, cattle, dogs and capybaras, respectively. Identical isoenzyme profiles, known as zymodeme 58 (T.evansi MCAN/BR/86/H), were found in all T.evansi stocks isolated in the study area (six from dogs, one from a horse and one from a capybara). From the results of this study it can be inferred that Mal de Cadeiras is endemic in Pantanal de Poconé. Although clinical and parasitological findings support the possible role of the capybara as a reservoir host of T.evansi, dogs and cattle--due to their close contact with horses--should rather be regarded as efficient reservoir hosts for Mal de Cadeiras in the study area.

Capybaras, Hydrochaeris hydrochaeris , scent mark with a sebaceous snout gland and anal glands, either separately or in sequence. In the Venezuelan llanos, marking was observed 3,864 times. A minority of marks was associated with aggressive interaction, but most marks were deposited out of any obvious context. Males marked more often than females, and the majority of marks with the snout gland was followed by marks with anal glands. Rates of marking by individuals were associated with social rank and decreased with group size.

Capybaras, (Hydrochoerus hydrochaeris) are large, herbivorous New World hystricomorphs, common in the seasonally flooded savannas of tropical and subtropical South America. In this paper we review the social structure and dynamics of capybaras across much of their geographic range. Wherever they have been studied capybaras live in groups. Capybara groups are stable social units composed of adult males and females (sex ratio biased toward females) with their young. A linear dominance hierarchy characterizes interactions among males, and the dominant male obtains most matings. Group sizes range from 6 to 16 adult members and vary with habitat characteristics and population density. At higher densities group sizes and the proportion of floaters (apparently unaffiliated animals; mostly males) increase. In 1 low-density location dispersal appears to occur in groups of both sexes, whereas in another location, where density is higher, males disperse and females are philopatric. We also discuss more conceptual issues (mostly proximate and ultimate mechanisms) that relate to intraspecific variation in social behavior in general, and capybaras in particular. © 2011 American Society of Mammalogists. Fil:Corriale, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.

En el presente estudio evaluamos la contribucion de especies de plantas C3, C4 e intermedias C3-C4, en la dieta de herbivoros nativos (Hydrochoerus hydrochaeris, Rhea americana y Logostomus maximus) y domesticos (reses), y analizamos la abundancia de las plantas presentes que muestran estos tipos foto sinteticos en distintos ambientes, de la seccion baja de la Cuenca de Rio Parana, Argentina, con clima similar pero regimenes hidrologicos diferentes. Los datos de la vegetacion y de la dieta, asi como sus tipos fotosinteticos, fueron obtenidos de datos bibliograficos. El analisis de la dieta anual realizada en terminos de tipos fotosinteticos, mostro que los patrones de consumo de los herbivoros silvestres y domesticos variaron espacial y temporalmente. El analisis de la vegetacion de cada sitio y la dieta de los herbivoros en primavera indicaron que los patrones de forrajeo no solo dependen de la disponibilidad de la vegetacion, sino tambien de la preferencia de los herbivoros y de las interacciones especificas entre estos bajo condiciones de recursos limitados. Estos atributos deberian ser considerados a la hora de hacer inferencias sobre las dietas y el ambiente de los herbivoros. Los estudios sobre grupos fotosinteticos actuales contribuyen a la interpretacion del analisis de isotopos estables del Carbono en la reconstruccion de las relaciones entre paleodietas y paleoambientes.

Muitas espécies de mamíferos selvagens são criadas para produção de carne. No Brasil, a capivara (Hydrochaeris hydrochaeris), a paca (Agouti paca), o cateto (Tayassu tajacu) e a queixada (Tayassu pecari) são criadas comercialmente para este fim, porém são escassas as informações sanitárias a respeito dessas espécies. Assim, o presente estudo teve por objetivo estudar a presença de infecção causada por leptospiras, micobactérias, brucelas e Erysipelothrix spp. em 138 animais dessas quatro espécies, provenientes de nove criadouros e abatidos em estabelecimento com Serviço de Inspeção Federal. Nenhum animal apresentou anticorpos séricos contra brucelas lisas. As capivaras apresentaram a maior freqüência de animais sorologicamente reagentes para leptospiras (54,5%), seguidas das queixadas (39%) e dos catetos (21,7%). O sorovar mais provável mais freqüente para as espécies estudadas foi o Grippotyphosa, seguido do Hardjobovis e do Tarassovi. Das capivaras foram isolados Leptospira santarosai a partir de rim e Mycobacterium xenopi a partir de linfonodo mesentérico. Das queixadas foi isolado Erysipelothrix rhusiopathiae a partir de tonsila. Segundo os bancos de dados Scopus, Pubmed e Cab Abstracts (Ovid), trata-se dos primeiros relatos de isolamento de M. xenopi em capivara e de E. rhusiopathiae em queixada. Many species of wild mammals are raised for meat production. In Brazil, the capybara (Hydrochaeris hydrochaeris), paca (Agouti paca), collared peccary (Tayassu tajacu) and the white-lipped peccary (Tayassu pecari) are commercially bred, however there is limited sanitary information related to these species. This study aimed to search for the presence of infection caused by Leptospira spp., Mycobacteria spp., Brucella spp. and Erysipelothrix spp. in 138 animals belonging to those species, coming from nine commercial breeders and slaughtered under the Federal Inspection Service. None of these animals presented antibodies against smooth brucellas. The capybaras showed the highest frequency of seropositive animals for leptospirosis (54.4%), followed by the white-lipped peccaries (39%) and the collared peccaries (21.7%). The most frequent serovar was Grippotyphosa, followed by Hardjobovis and Tarassovi. Leptospira santarosai was isolated from the kidneys and Mycobacterium xenopi from the mesenteric lymph nodes of the examined capybaras. Erysipelothrix rhusiopathiae was isolated from the tonsils of one white-lipped peccary. According to the data banks Scopus, Pubmed e Cab Abstracts (Ovid), this is the first report of M. xenopi isolation from capybara and of E. rhusiopathiae from white-lipped peccary.

Cet ouvrage dédié au Capybara a pour objectif de faciliter, en milieu spécialisé sur les animaux de faune sauvage, l’obtention de clichés radiographiques de qualité, ainsi que leur interprétation. Après une partie consacrée à la présentation du Capybara, on rappelle le principe de l’examen radiographique et donne les réglages utilisés. Les radiographies, présentées en deux exemplaires (avec et sans légende) sont accompagnées des photographies détaillées de la structure osseuse correspondante.

The volume of the morrillo (snout scent-gland) of adult capybara ( Hydrochaeris hydrochaeris ) males was found to correlate significantly with testes mass ( r = 0.359, d.f. = 110, P < 0.0001). This was independent of body size. Males in better condition did not have larger testes or morrillos, whereas age did correlate with size of the morrillo and testes. These results were related to the higher rates of scent marking and reproductive success of dominant males reported in previous studies.

El propósito del trabajo fue determi‑ nar la prevalencia del trematodo Fasciola hepatica en carpinchos (Hydrochaeris hydrochaeris) de la Provincia de Corrientes (Argentina) y el rol que podría cumplir en la epizootiología de la fasciolosis hepática para otras especies hospedadoras del parásito. Para comprobar la presencia del trematodo se obtuvieron 18 hígados de carpinchos silvestres provenientes de distintas zonas de Corrientes. Del total de órganos examinados, solamente un caso resultó positivo a F. hepatica (5,56%), identificándose 10 ejemplares por sus caracteres morfológicos y la presencia de abundantes de huevos típicos que se recuperaron durante el examen. Este hallazgo debe considerarse como la primera comunicación del parasitismo de F. hepatica en H. hydrochaeris en el país. The purpose of the study was to determine the prevalence of the fluke Fasciola hepatica in capybaras (Hydrochaeris hydrochaeris) from Corrientes, Argentina, for its possible role in the epizootiology of hepatic fasciolosis in other possible hosts. For this reason, 18 liver samples of wild capybaras were obtained from dif‑ ferent areas of Corrientes. For the total of the organs analyzed, only one liver harbored the parasites, identifying 10 specimens according to morphological characteristics and the pres‑ ence of abundant typical eggs collected during the examination. We consider this finding as the first communication for the country regarding the parasitism by F. hepatica on H. hydrochaeris. Fil: Ortiz, Maria Isabel. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina Fil: Alvarez, J. D.. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina Fil: Moriena, Ricardo Antonio. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina Fil: Ortiz, M. I.. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina Fil: Racoppi, O.. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina

Fil: Álvarez, José Darío. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: Moriena, R. A. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: Ortíz, M. I. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Fil: Racioppi, Oscar. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. El propósito del trabajo fue determinar la prevalencia del trematodo asciola hepatica en carpinchos (Hydrochaeris hydrochaeris) de la Provincia de Corrientes (Argentina) y el rol que podría cumplir en la epizootiología de la fasciolosis hepática para otras especies hospedadoras del parásito. Para comprobar la presencia del trematodo se obtuvieron 18 hígados de carpinchos silvestres provenientes de distintas zonas de Corrientes. Del total de órganos examinados, solamente un caso resultó positivo a F. hepatica (5,56%), identificándose 10 ejemplares por sus caracteres morfológicos y la presencia de abundantes de huevos típicos que se recuperaron durante el examen. Este hallazgo debe considerarse como la primera comunicación del parasitismo de F. hepatica en H. hydrochaeris en el país. The purpose of the study was to determine the prevalence of the fluke Fasciola hepatica in capybaras (Hydrochaeris hydrochaeris) from Corrientes, Argentina, for its possible role in the epizootiology of hepatic fasciolosis in other possible hosts. For this reason, 18 liver samples of wild capybaras were obtained from dif‑ ferent areas of Corrientes. For the total of the organs analyzed, only one liver harbored the parasites, identifying 10 specimens according to morphological characteristics and the pres‑ ence of abundant typical eggs collected during the examination. We consider this finding as the first communication for the country regarding the parasitism by F. hepatica on H. hydrochaeris.

The aim of this work was to study the short and long term influences of ascorbic acid on Hydrochoerus hydrochaeris, if supplemented in their food. No differences regarding food intake were observed in the absence of vitamin C. On a daily basis, animals accustomed to food containing ascorbic acid prefered to continue eating the same food. Food preference in capybaras did not seem to depend on ascorbic acid availability; however, when accustomed to vitamin C, capybaras might recognize and select ascorbic acid in subsequent food. Mechanisms allowing capybaras to "evaluate" the nutritional quality of their food are discussed, as well as the adaptive value of this behavior in free ranging populations. © 2009 Tecpar. Fil:Kravetz, F.O. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.

A study of the 24‐hour cycle of activity in Capybaras in the llanos of Venezuela was made using visible red light for nocturnal activity. Observations were made during both the dry and rainy season. In both cases Capybaras showed 4 peaks of activity during the 24‐hour cycle, but in the dry season 3 peaks were after dark while in the wet season 2 peaks were by day and 2 by night. By night groups of Capybaras moved rapidly to grazing sites keeping together by low volume vocal communication. Experimentation showed that visible red light permits close approach to Capybaras because it hides the observer. Coprophagy was frequently observed, almost exclusively during the morning resting period. Copulations were observed mostly in May (dry season), all but one in water, and most between 08.00 to 13.00. It is suggested that censuses for establishing harvest quotas avoid resting periods because important proportions of Capybaras may be hidden in thickets or aquatic vegetation.

Body mass in extant rodents covers more than four orders of magnitude, from a few grams up to 40 kg on average in the capybara ( Hydrochaeris hydrochaeris ; [Silva & Downing 1995][1]). However, rodents have been much bigger in the past. The South American fossil rodent, Phoberomys pattersoni ([

The young semi-confined capibaras behavior was studied from 27th August to 24th September, in 2001, in Floriano - Paraná State, Brazil. A group of nine capibaras was placed in confinement in a picket to have dips during all the experience, while another group of animals had no access to such dips. Weather conditions were registered every hour. There was no difference regarding the animals’ behavior during the treatment, which suggests the possibility of pickets with no pools for grown-up semi-confined capibaras. When there is no shadow against sun irradiation, the ‘pool’ has great importance for the relief of caloric stress. The feeding places, which were arranged linearly, caused great stress on the animals’ handling. This work was based on research with animals in their natural habitat due to the scarcity of research concerning the breeding of Hydrochaeris hydrochaeris Entre os dias 27 de agosto e 24 de setembro de 2001 estudou-se o comportamento de capivaras jovens em semiconfinamento no Distrito de Floriano, Estado do Paraná. Um grupo de nove animais foi alojado em um piquete com acesso a banhos de imersão durante todo o experimento, enquanto o outro permaneceu sem acesso a tal recurso. Os dados climáticos foram registrados a cada hora. Não foram verificadas diferenças no comportamento entre os tratamentos, sugerindo a possibilidade de piquetes sem piscina para capivaras em crescimento e em regime de semiconfinamento. Em casos de insuficiência de sombra para a proteção da radiação solar, o recurso “piscina” tem grande importância no alívio do estresse calórico. Os comedouros dispostos de forma linear foram os maiores estressores no manejo dos animais. Pela escassez de pesquisas com Hydrochaeris hydrochaeris em regime de produção, as discussões deste trabalho tiveram como comparativos pesquisas realizadas com animais em habitat natural

33-44 rubenq@biolo.bg.fcen.uba.ar semestral Referencia analítica

O monitoramento semanal de um grupo de capivaras (Hydrochaeris hydrochaeris) foi realizado durante 12 meses (fevereiro/2003 a janeiro/2004) ao anoitecer. As observações consistiram na coleta de informações comportamentais, classificação etária e contagem direta de indivíduos avistados durante o pastejo. No período de estudo, foi feita uma captura, com a contenção dos animais, pesagens, sexagens, marcações, bem como a definição das classes etárias dos 15 animais apreendidos. A densidade ecológica média foi de 0,58±0,05ind ha-1 e o número médio de indivíduos foi de 21±5,6. O grupo apresentou uma mudança de comportamento, com o aumento da área de pastejo e a diminuição do número de indivíduos, principalmente jovens, causando uma diminuição da densidade ecológica da população nos meses de junho a setembro de 2003. Machos jovens foram provavelmente expulsos dos grupos não somente em virtude do período reprodutivo, mas também como uma medida de ajuste populacional em função da escassez de alimento. O aumento da área de vivência durante a seca, juntamente à provável expulsão de indivíduos em função da alimentação e/ou reprodução, mostraram a capacidade da espécie em driblar condições pouco favoráveis encontradas durante o ano. A capybara (Hydrochaeris hydrochaeris) population was monitored weekly at nightfall for 12 months (February 2003 to January 2004). Information about behavior, age class and animal number at pasture activities were collected during the observations. Fifteen animals were captured once and thus, their contention, weighing, identifications, sex definition, as well as, the age class confirmation could be done. The average ecological density was 0,58±0,05ind ha-1 and the mean individual number was 21±5,6. The capybara group changed its behavior by increasing the pasture area and decreasing the number of animals observed (mainly juveniles) from June to September (2003). Juvenile males were probably banished from the group to provide population adjust because of reproduction season and food scarcity. Home-range increase during dry season added to animals' banishment for food and/or reproduction reasons show the capybaras' ability to react against difficult environmental conditions during the year.

Capybaras are the largest of living rodents and are the most common wild rodent in the state ofRio Grande do Sul, Brazil. They are commercially bred for their meat, hide, and oil. The presentstudy aims to shed some light upon intestinal protozoa of capybaras using Sheather’s methodmodified by Benbrook to analyze 250 fecal samples. The following Eimeria species were detected000in 52.4% of the fecal samples: E. trinidadensis, E. ichiloensis, E. boliviensis, in addition to anotherspecies that could not be identified. With regard to the total oocyst count, the relative frequency ofdifferent Eimeria species was as follows: E. trinidadensis (55%), E. ichiloensis (32.6%), E.boliviensis (4.8%), and an unidentified Eimeria species (7.6%). The unidentified species was called Eimeria araside sp.n. (Apicomplexa: Eimeriidae). Key words: capybara, Eimeria , faeces. that affects the small and/or large intestine and iscaused by different Eimeria species 4 . It usuallyoccurs among young animals, whereassuccessive infections in adult animals make theirbody develop a resistant immune system, turningthem into carriers of the disease