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Given the high prevalence of skeletal and mandibular diseases in the Patagonian Huemul, comprehensive anatomical studies are essential to understand the impact of nutritional deficiencies and support conservation efforts. The aim of this study is to provide a detailed anatomical characterisation of three exhumed mandibles of Patagonian huemul (Hippocamelus bisulcus) through three-dimensional reconstructions obtained from computed tomography data and semi-automatic segmentation, documenting their distinctive features. The findings revealed distinctive features in the mandible, consistent with the browsing habits of herbivores, such as a robust coronoid process, a wide and deep pterygoid fossa, a significantly lower mandibular condyle compared to other deer species and a unique configuration of the mandibular canal with a curved caudal portion and a straight rostral portion. These anatomical adaptations are likely related to the species' feeding habits and behaviour. The study also addressed the challenges of researching an endangered species, given that access to biological material is restricted by strict regulations in Chile and Argentina. These restrictions limited the available sample size and hindered the acquisition of additional specimens, which could affect the generalisation of the results. Despite these limitations, the research provides valuable anatomical insights that are fundamental for the biology, clinical practice and management of specimens. In conclusion, the mandibles of both juvenile and adult Patagonian huemul demonstrate distinctive features characteristic of browsing herbivores. The findings can serve as a basis for future comparative studies on mandibular anatomy and function in this endangered deer species as well as in other herbivorous deer.

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Studies of the normal skull anatomy of the Patagonian Huemul deer are scarce. Currently, the findings of bone lesions in the skull associated with metabolic imbalances are frequent in the literature. The objective of this study was to provide anatomical and morphometric data of the cranium and facies including a morphofunctional interpretation as a reference for clinical, ecomorphological and educational purposes. Five skulls were described, measured, scanned and digitally reconstructed. The presence of a caudal projection of the vomer bone, the absence of the facial tubercle and thin bones forming the cranial cavity were observed. Linear measurements allowed the skull to be classified as dolichocephalic, hyperlepten and ultra-dolichocranial. In conclusion, the Patagonian Huemul has a long head, an extremely long skull and a very narrow face. The thickness of the bones that made up the walls of the cranial cavity suggests chronic metabolic imbalances in response to mineral deficiency. The anatomical and morphometric data obtained in this study strongly emphasizes the relevance of considering the implementation of such management policies that aim at promoting an optimal nutritional context.

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Defaunation is a global threat to biodiversity that can be counteracted through trophic rewilding, a restoration strategy that promotes self-regulating ecosystems through active reintroductions or passive management. In order to estimate success in restoration initiatives, progress of the rewilding projects is measured and monitored. However, a spatially explicit understanding of rewilding and rewilding potential in a rewilding site has been absent so far. We present a novel approach for monitoring rewilding progress that focuses on a spatially explicit estimate of progress and ecological integrity within rewilding initiatives. This framework uses habitat classification of the site and tracking data of the reintroduced animals, to model their habitat selection. Through this we measure and map realized and potential rewilding. We operationalize the framework in an ongoing rewilding project in the Iberá Wetlands, Corrientes, Argentina. The majority of areas (76%) predicted to be occupied by reintroduced fauna were only predicted to be selected by one species. Of the four species in the rewilding project, only the giant anteater (Myrmecophaga tridactyla) filled the majority of its potential distribution, whereas pampas deer (Ozotoceros bezoarticus), collared peccary (Pecari tajacu) and lowland tapir (Tapirus terrestris) filled less than 23% of theirs. After rewilding we found a 10% increase in the proportion of the study area with high ecological integrity. Through this case study, we showed that this framework can be used to assess the spatial progress of a rewilding site. By incorporating wildlife tracking and satellite-based remote sensing, we are integrating a spatial component to monitoring of rewilding projects that should lead to more detailed understanding of the progress of rewilding. Applying this framework would facilitate decision-making for practitioners and inform species management plans.

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Accurate species-level identification of the source of arthropod bloodmeals is important for deciphering blood feeding patterns of field-collected specimens. Cytochrome c oxidase I (COI) mitochondrial gene sequencing has been used for this purpose; however, species resolution can be difficult to obtain from certain vertebrate genera, including Odocoileus. Sanger sequencing of mitochondrial genes was employed to identify the bloodmeal source of wild-caught mosquitoes trapped in Greeley, Colorado. Initial sequencing of the COI gene of mitochondrial DNA in bloodmeals was inadequate for species-level resolution of bloodmeals from deer in the genus Odocoileus, with current databases returning low fidelity matches to multiple genera. The use of the hypervariable D loop of the control region provided species-level identification of white-tailed deer (Order: Artiodactyla, Family: Cervidae, Odocoileus virginianus); however, taxonomic identification was successful only to genus for mule (O. hemionus hemionus) and black-tailed deer (O. hemionus columbianus). We advocate the use of multiple loci for bloodmeal analysis and the buildout of available databases to include multiple mitochondrial reference genes for reliable host species identification.

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A introdução de dispositivos intravaginais em protocolos tradicionais de sincronização do estro (SE) exige contenção física e/ou química, o que pode resultar em estresse e efeitos negativos na fisiologia reprodutiva de animais selvagens. Portanto, o uso de protocolos não invasivos pode ser mais eficaz para o manejo da reprodução ex situ. O objetivo deste estudo foi avaliar a eficácia do acetato de melengestrol (MGA), na SE de uma fêmea de veado-mão-curta (Mazama nana) e uma de veado-roxo (Mazama nemorivaga). Ambas receberam uma aplicação via intramuscular de 0,25 mg de benzoato de estradiol (Sincrodiol® ) no dia 0 (D0). Entre o D0 e o D7, foi administrado 1 mg/animal/dia de MGA® Premix fracionado em duas porções (0,5 mg pela manhã e 0,5 mg a tarde), misturadas com banana. No D8, um análogo de PGF2α (Cloprostenol - Ciosin® ) foi administrado via intramuscular. Após o tratamento, o estro comportamental (EC) foi avaliado com auxílio de um macho da respectiva espécie desde D9 a D13, primeiramente a cada seis horas e, após o início do EC, a cada quatro horas. As duas fêmeas apresentaram sinais de EC nos dias 12 e 13. Na espécie Mazama nana, o EC teve uma duração aproximada de 16 horas e, na espécie Mazama nemorivaga, 20 horas. Os resultados obtidos neste estudo sugerem a eficácia da dose de 1,0 mg/animal/dia de MGA, fracionada em duas doses, na manipulação estral em fêmeas de veado-mão-curta e veado-roxo, uma vez que ambas demonstraram EC quatro dias após o protocolo de sincronização proposto.

The introduction of intravaginal devices in traditional estrus synchronization protocols requires physical and/or chemical restraint, which can result in stress and negative effects on the reproductive physiology of wild animals. Therefore, the use of non-invasive protocols might be more effective for the reproductive management ex situ. The objective of this study was to evaluate the efficacy of the melengestrol acetate (MGA) for estrus synchronization of two females: one deer-short-hand (Mazama nana) and one deer-purple (Mazama nemorivaga). Both were given an application of estradiol benzoate (Sincrodiol® ) on day 0 (D0). From D0 to D7, 1 mg/female/day of oral MGA® Premix was fractionated in two administrations (0.5 mg morning and 0.5mg afternoon) mixed with banana. On D8, a PGF2α analogue were given intramuscularly (Cloprostenol - Ciosin® ). After treatment, behavioural estrus was evaluated with the aid of a male of the respective species from D9 to D13, initially every six hours then every four hours after the onset of behavioural estrus. The two females showed behavioural estrus on days 12 and 13. In the Mazama nana, the behavioral estrus had duration of approximately 16 hours and in the Mazama nemorivaga 20 hours. The results obtained in this study suggest the efficacy of 1.0 mg/female/day of MGA fractionated in two doses for the estrus manipulation in deer-short-hand and deer-purple females, since both showed behavioural estrus four days after the proposed synchronization protocol.

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Given the difficulty of collecting biological samples from rare and elusive species, the collection and analysis of hair is a good alternative for the identification and differentiation of mammal species. Our study aimed to test the reliability of the morphological identification of guard hairs from cervids that inhabit Brazil. We collected guard hairs from five body regions (head, neck, side of the thorax, back, and buttocks) of one male and one female of eight Brazilian cervid species, and we analyzed hair cuticular and medullar patterns. We carried out qualitative and quantitative analyses on the morphology of the medullar (total thickness and thickness of the medulla) and cuticular patterns (area and perimeter of the scales) of the guard hairs. Based on the obtained data, we found no notable morphological differences in the cuticular and medullar patterns in the guard hairs. Furthermore, our quantitative analysis demonstrated that the guard hairs are not a useful material for differentiating the Brazilian deer species.

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A introdução de dispositivos intravaginais em protocolos tradicionais de sincronização do estro (SE) exige contenção física e/ou química, o que pode resultar em estresse e efeitos negativos na fisiologia reprodutiva de animais selvagens. Portanto, o uso de protocolos não invasivos pode ser mais eficaz para o manejo da reprodução ex situ. O objetivo deste estudo foi avaliar a eficácia do acetato de melengestrol (MGA), na SE de uma fêmea de veado-mão-curta (Mazama nana) e uma de veado-roxo (Mazama nemorivaga). Ambas receberam uma aplicação via intramuscular de 0,25 mg de benzoato de estradiol (Sincrodiol® ) no dia 0 (D0). Entre o D0 e o D7, foi administrado 1 mg/animal/dia de MGA® Premix fracionado em duas porções (0,5 mg pela manhã e 0,5 mg a tarde), misturadas com banana. No D8, um análogo de PGF2α (Cloprostenol - Ciosin® ) foi administrado via intramuscular. Após o tratamento, o estro comportamental (EC) foi avaliado com auxílio de um macho da respectiva espécie desde D9 a D13, primeiramente a cada seis horas e, após o início do EC, a cada quatro horas. As duas fêmeas apresentaram sinais de EC nos dias 12 e 13. Na espécie Mazama nana, o EC teve uma duração aproximada de 16 horas e, na espécie Mazama nemorivaga, 20 horas. Os resultados obtidos neste estudo sugerem a eficácia da dose de 1,0 mg/animal/dia de MGA, fracionada em duas doses, na manipulação estral em fêmeas de veado-mão-curta e veado-roxo, uma vez que ambas demonstraram EC quatro dias após o protocolo de sincronização proposto.(AU)

The introduction of intravaginal devices in traditional estrus synchronization protocols requires physical and/or chemical restraint, which can result in stress and negative effects on the reproductive physiology of wild animals. Therefore, the use of non-invasive protocols might be more effective for the reproductive management ex situ. The objective of this study was to evaluate the efficacy of the melengestrol acetate (MGA) for estrus synchronization of two females: one deer-short-hand (Mazama nana) and one deer-purple (Mazama nemorivaga). Both were given an application of estradiol benzoate (Sincrodiol® ) on day 0 (D0). From D0 to D7, 1 mg/female/day of oral MGA® Premix was fractionated in two administrations (0.5 mg morning and 0.5mg afternoon) mixed with banana. On D8, a PGF2α analogue were given intramuscularly (Cloprostenol - Ciosin® ). After treatment, behavioural estrus was evaluated with the aid of a male of the respective species from D9 to D13, initially every six hours then every four hours after the onset of behavioural estrus. The two females showed behavioural estrus on days 12 and 13. In the Mazama nana, the behavioral estrus had duration of approximately 16 hours and in the Mazama nemorivaga 20 hours. The results obtained in this study suggest the efficacy of 1.0 mg/female/day of MGA fractionated in two doses for the estrus manipulation in deer-short-hand and deer-purple females, since both showed behavioural estrus four days after the proposed synchronization protocol.(AU)

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Given the difficulty of collecting biological samples from rare and elusive species, the collection and analysis of hair is a good alternative for the identification and differentiation of mammal species. Our study aimed to test the reliability of the morphological identification of guard hairs from cervids that inhabit Brazil. We collected guard hairs from five body regions (head, neck, side of the thorax, back, and buttocks) of one male and one female of eight Brazilian cervid species, and we analyzed hair cuticular and medullar patterns. We carried out qualitative and quantitative analyses on the morphology of the medullar (total thickness and thickness of the medulla) and cuticular patterns (area and perimeter of the scales) of the guard hairs. Based on the obtained data, we found no notable morphological differences in the cuticular and medullar patterns in the guard hairs. Furthermore, our quantitative analysis demonstrated that the guard hairs are not a useful material for differentiating the Brazilian deer species.(AU)

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The fallow deer (Dama dama) is a species of Cervidae commonly kept in captivity, either in commercial farms or in zoos. The reproductive seasonality of this species is well known in the northern hemisphere, where photoperiod is a decisive factor in androgenic activity and, consequently, in the development of secondary sexual characteristics among male adults. The maintenance of this species in tropical regions has been successful, but there are no studies that demonstrate the maintenance of reproductive seasonality under these climatic conditions, which was the objective of the present study. To do so, the present investigation involved 27 fallow deer (D. dama) specimens, of which 14 were adults and 13 prepubescent (<8 months) individuals, all assessed during and outside (December-February) the reproductive season (June-August). The serum concentrations of testosterone, testicular volume, and neck circumference were analyzed among all animals during both seasons. The reproductive season was marked by expressive hormonal concentrations, increasing neck circumference and testicular volume, differing significantly between adults and prepubescent individuals outside the season. Positive correlations were observed among all analyzed variables: mean testicular volume and neck circumference (r = 0.92, p < 0.0001), testicular volume and testosterone concentrations (r = 0.79, p < 0.0001) and between neck circumference and testosterone concentrations (r = 0.67, p < 0.0001). Given the results found, the conclusion is that even under tropical climate conditions the reproductive seasonality of the fallow deer is well defined and may be related to photoperiod.

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The study of predator-prey interactions is commonly analyzed using functional responses to gain an understanding of predation patterns and the impact they have on prey populations. Despite this, little is known about predator-prey systems with multiple prey species in sites near the equator. Here we studied the functional response of cougars (Puma concolor) in relation to their main prey, armadillo (Dasypus novemcinctus), coati (Nasua narica) and white-tailed deer (Odocoileus virginianus). Between 2004 and 2010, cougar scats were collected along 5 transects to estimate the consumption of different prey species. A relative abundance index (RAI) was calculated for each prey species and cougar using 18 camera traps. We compared Holling type I, II and III functional response models to determine patterns in prey consumption based on the relative abundance and biomass of each prey species consumed. The 3 main prey species comprised 55% (armadillo), 17% (coati) and 8% (white-tailed deer) of the diet. Type I and II functional responses described consumption of the 2 most common prey species armadillos and coati similarly well, while a type I response best characterized consumption of white-tailed deer. A negative correlation between the proportions of armadillo versus coati and white-tailed deer biomass in cougar scats suggests switching to consume alternative prey, confirming high foraging plasticity of this carnivore. This work represents one of the few studies to compare functional responses across multiple prey species, combined with evidence for prey-switching at low densities of preferred prey.

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OBJECTIVE: The last 1500 endangered Patagonian huemul deer (Hippocamelus bisulcus) exist in > 100 groups which are not recovering. Prevalence of osteopathology in dead huemul was 57+% (Argentina), whereas similar cases in Chile were accompanied by selenium deficiency. The first clinical cases from live wild huemul confirm widespread osteopathology which explains short life spans, low recruitment, and thus absence of population recovery. RESULTS: The first-ever radio-collaring of 3 male huemul in Argentina and 3 females, plus a fresh female carcass allowed examination of 7 huemul. Of these, 86% were diseased and clinical pathophysiognomy included lameness, affected hoof, exfoliation of 2-7 incisors, other cranial osteopathologies, and muscle atrophy. The parsimonious explanation for absent population recovery is high prevalence of osteopathology as evidenced earlier in carcasses, and now by these clinical cases. Areas currently used by huemul have reduced selenium bioavailability, very deficient soil levels, and overt selenium deficiency in local livestock and plants. These areas are known to result in primary iodine deficiency which is aggravated by selenium deficiency. The nexus to nutritional ecology of huemul likely is inaccessibility to most fertile lowlands and traditional winter ranges, elimination of migratory traditions, and concomitant elimination of source populations.

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Information about gonadal asymmetries in ruminants is very scarce. In this work, we performed three complementary studies to compare characteristics of both testes: (i) weight and size of offspring and adult dead males; (ii) the tissue:fluid relationship determined by ultrasound scanning; and (iii) the spermatogenic status using fine needle aspiration cytology. The right testis was heavier than the left one in both offspring and adult animals and had greater width and volume in adult males than the left one. The ultrasound pixel intensity was similar in both testes. The right testis tended to have more spermatogonia (p = .06) and had a greater percentage of early spermatids (p = .004) than the left testis. On the other hand, the left testis had a greater percentage of spermatozoa (p = .05). The left testis had a greater spermatozoa/spermatogonia ratio (p = .02) and tended to have more spermatozoa/Sertoli cells ratio (p = .07). The spermatogenic index tended to be greater in the left than in the right testis (p = .06). Overall, we concluded that the right testis of pampas deer males is bigger but according to the cytology, it seems to be less spermatogenically effective than the left one, but these differences are not explained by different tissue:fluid ratio in each testis. Although differences were greater in adults than in offspring, asymmetry was observed even in just born offspring.

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The red brocket (Mazama americana) is a South American deer with a wide geographical distribution that presents different chromosomal variants depending on their location. At least six different cytotypes belonging to two distinct evolutionary lineages have been described. This study aimed to verify the existence of postzygotic reproductive isolation between cytotypes of M. americana by comparative evaluation of pure and hybrid males. Seven 18-month-old bucks were submitted to seminal collection and evaluation and testicle histological evaluations. The pure males showed normal parameters for sperm quality and testicular histology. Hybrids from the same evolutionary lineage (≤3 chromosomes different from the progenitors) showed similar results to pure males, except for the reduced ratio of round spermatids to pachytene spermatocytes. Hybrids between cytotypes of different evolutionary lineages (≥10 chromosomes different from progenitors) presented azoospermia and evidence of testicular degeneration. Despite the striking morphological similarities, we can conclude that populations with more distinct karyotypes possess an effective reproductive barrier; moreover, there is evidence that reproductive isolation mechanisms exist between some closer karyotypes, corroborating the hypothesis that M. americana is best characterized as a superspecies. Thus, the future description of several new species for this taxon is expected, since the tendency is to establish efficient mechanisms of postzygotic reproductive isolation, preventing the introgression and fusion of genomes from different populations through chromosome variation.

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The white-tailed deer ( Odocoileus virginianus) inhabits a wide latitudinal range in the Americas. Deer species dwelling throughout wide latitudinal ranges have developed subspecies with variations in their reproductive seasonality. In northern subspecies of white-tailed deer, such as those from Canada and the United States, the breeding season occurs from October through December. Odocoileus virginianus veraecrucis is a subspecies that inhabits eastern Mexico, and because its reproductive season has not been studied, it is believed to be similar to that from northern subspecies. The objective of the study was to determine the onset of the breeding season and the profile of fecal steroid hormone metabolites throughout the year in captive white-tailed deer subspecies veraecrucis in Mexico. Two groups of adult deer were included: 1) six does and one buck at a Wildlife Conservation Unit, and 2) five does and one buck at a zoo. From each group of deer, representative fecal samples were collected on a weekly basis for 1 yr for fecal analysis of progesterone and estradiol in the does, and testosterone in the bucks. Data on antler casting, parturitions, and velvet shedding were recorded. Progesterone was high during pregnancy and low throughout the parturition period. Estradiol fluctuated throughout the year. Testosterone was high during the rut and low after antler casting. Antlers were cast in March and velvet was shed in August at both sites. Parturitions started in February at the zoo and in April at the Wildlife Unit. In captive white-tailed deer subspecies veraecrucis the breeding season started in July, and therefore earlier than what has been reported for subspecies from northern latitudes.

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BACKGROUND: About 1,000 endangered Patagonian huemul deer (Hippocamelus bisulcus) remain in Chile and 350-500 in Argentina. Most groups (>100) are not recovering, and prevalence of osteopathology in Argentina was at least 57%. Here I describe relevant cases of osteopathology from a Chilean population which, however, recently also provided data on trace mineral status, supporting the initial hypothesis that nutrition may be a primary etiologic factor. Additionally, recent data on bone chemical composition of Argentine cases and soil analyses are discussed. RESULTS: Fluoride levels in Argentine cases with osteopathology were low and fluorosis was discarded as an etiological factor. Selenium deficiency occurred in 73% of huemul from the Chilean population which exhibited several cases with osteopathology. The pathophysiognomy included extensive erosion; tooth loss; porosification; perforations of palate, maxillar and mandibular bone with frequent exposure of tooth roots; and fractured mandibula. Areas currently used by remaining huemul have mainly acidic volcanic soils, which reduces selenium bioavailability: mean soil selenium levels from areas typically used by extant huemul were very deficient (0.19 ppm), corroborating documented overt selenium deficiency in local livestock and plants. The area of extant huemul is known to result in primary iodine deficiency in livestock which is aggravated by selenium deficiency. CONCLUSIONS: Currently the most parsimonious explanation for frequent osteopathology and lack of numerical recovery are the combined effects of selenium and iodine deficiencies based on: osteopathology in a population of selenium deficient huemul; selenium deficient livestock, plants and soils; acidic soils; and regional primary iodine deficiency. The nexus between mineral nutrition and population dynamics of huemul may be due to constraints on their movements to fertile lowlands, including the elimination of historic migratory traditions, and concomitant elimination of source populations.

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BACKGROUND: Restricted space and close contact with conspecifics in captivity may be stressful for musk deer, as they are highly territorial and solitary in the wild. So we tested the effects of crowding on stress of forest musk deer (Moschus berezovskii) in heterosexual groups, using fecal cortisol analysis as a non-invasive method. 32 healthy adults during non-breeding seasons were chose as our experimental objects. Group 1 was defined as higher crowding condition, with 10-15 m2/deer (6 enclosures, 10♀ and 6♂); group 2 was defined as lower crowding condition, with 23-33 m2/deer (6 enclosures, 10♀ and 6♂). Every enclosure contained 1 male and 3 female. These patterns had been existed for years. RESULTS: The results showed that females in lower crowding condition (217.1 ± 9.5 ug/g) had significantly higher fecal cortisol levels than those in higher crowding condition (177.2 ± 12.1 ug/g). Interestingly, crowding seemed have no effect on male fecal cortisol levels (148.1 ± 9.1 ug/g and 140.5 ± 13.3 ug/g, respectively). At both groups, cortisol was significantly lower in males than in females. CONCLUSIONS: These results showed that chronic crowding may affect stress status of captive forest musk deer. The captive environment should consider the space need for musk deer.

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Forage use and availability for white tailed deer Odocoileus virginianus thomasi (Artiodactyla: Cervidae) in an experimental unit of Campeche, Mexico. In Campeche state, 122 Wildlife Conservation and Management Units have been recently conformed. In these units, eventhough the white tailed deer Odocoileus virginianus thomasi is a game species, no studies on its diet have been undertaken. The objectives of this work were to estimate the botanical composition of the diet and its seasonal change, to determine forage availability, carrying capacity and stocking rate of O. virginianus thomasi. The study was conducted in the experimental unit of Colegio de Postgraduados in Campeche, Mexico, from October 2010 to May 2012. The diet was determined through microhistological analyses of the white tailed deer feces by the use of reference material. Forage availability was determined through the Adelaide's method; the stocking rate, using the grazing pressure factor; and carrying capacity considering forage availability and 35% of utilization efficiency. In this experimental unit, the deer diet included 40 species belonging to 15 families. The highest species richness ocurred during the rainy season with 29 species. However, deers preferred shrubs during all seasons, and herbaceous species during the rainy season. The diet composition, forage availability, carrying capacity and stocking rate varied throughout the year. Carrying capacity ranged from 0.04 to 1.08deer/ha. Additional studies are required to detail about the composition of the diet, habitat availability and use throughout its geographical range, and to detail on nutritional and health aspects.

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In Campeche state, 122 Wildlife Conservation and Management Units have been recently conformed. In these units, eventhough the white tailed deer Odocoileus virginianus thomasi is a game species, no studies on its diet have been undertaken. The objectives of this work were to estimate the botanical composition of the diet and its seasonal change, to determine forage availability, carrying capacity and stocking rate of O. virginianus thomasi. The study was conducted in the experimental unit of Colegio de Postgraduados in Campeche, Mexico, from October 2010 to May 2012. The diet was determined through microhistological analyses of the white tailed deer feces by the use of reference material. Forage availability was determined through the Adelaide´s method; the stocking rate, using the grazing pressure factor; and carrying capacity considering forage availability and 35% of utilization efficiency. In this experimental unit, the deer diet included 40 species belonging to15 families. The highest species richness ocurred during the rainy season with 29 species. However, deers preferred shrubs during all seasons, and herbaceous species during the rainy season. The diet composition, forage availability, carrying capacity and stocking rate varied throughout the year. Carrying capacity ranged from 0.04 to 1.08deer/ha. Additional studies are required to detail about the composition of the diet, habitat availability and use throughout its geographical range, and to detail on nutritional and health aspects. Rev. Biol. Trop. 62 (2): 699-710. Epub 2014 June 01.

En Campeche, México no existen estudios de la dieta de Odocoileus virginianus thomasi; a pesar de la existencia de 122 Unidades de Manejo para la Conservación de la Vida Silvestre (UMAS) en donde se realiza aprovechamiento del venado cola blanca. Los objetivos del trabajo fueron conocer la composición botánica de la dieta y su cambio estacional, la disponibilidad de forraje, la capacidad de carga y carga animal de O. virginianus thomasi. El trabajo se realizó de octubre 2010 a mayo 2012 en el Campo Experimental del Colegio de Postgraduados en Campeche, México. La composición de la dieta se determinó mediante el análisis de heces de venado y material de referencia con la técnica microhistológica; la disponibilidad de forraje se estimó con el método de Adelaide; la capacidad de carga utilizando la presión de pastoreo y la carga animal considerando el forraje disponible y 35% de eficiencia de utilización. La dieta incluyó 40 especies de 15 familias. La riqueza de especies más alta fue de 29 especies en la época de lluvia; las arbustivas fueron preferidas en las tres épocas del año y las herbáceas en la época de lluvia. La composición de la dieta, disponibilidad de forraje, la capacidad de carga y carga animal variaron a través del año. La capacidad de carga fluctuó entre 0.04 a 1.08 venados/ha.

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Our objectives were to determine if success index of pampas deer females is related with females' age and if social rank makes any influence on reproductive performance. Female social rank was determined in 18 groups of animals composed of 1 male: 5-9 females (total=98 females). Date of parturition for each female and sex and birth weight of fawns were recorded for each birth. The females were categorized in three hierarchical ranks: low (<0.33) (group LR), medium (0.33-0.66) (group MR), and high (>0.66) (group HR). The success index increased with age in pampas deer females (P<0.001). Social rank had no effect on calving success, relative calving dates, sex ratio or body weight at birth. In this study, the success index was related with females' age, and the reproductive performance did not differ between females of different social ranks.

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BACKGROUND: The red brocket deer, Mazama americana, has at least six distinct karyotypes in different regions of South America that suggest the existence of various species that are today all referred to as M. americana. From an evolutionary perspective, the red brockets are a relatively recent clade that has gone through intense diversification. This study sought to prove the existence of post-zygotic reproductive isolation in deer offspring between distinct chromosome lineages. To achieve this, inter-cytotype and intra-cytotype crosses were performed, which resulted in both F1 hybrid (n = 5) and pure offspring (n = 3) in captivity. RESULTS: F1 females were analyzed in terms of their karyotypes, ovarian histology, estrous cycles and in vitro embryo production. Pure females presented parameters that were similar to those previously reported for M. Americana; however, the parameters for hybrid females were different. Two hybrids were determined to be sterile, while the remaining hybrids presented characteristics of subfertility. CONCLUSIONS: The results support the existence of well-established reproductive isolation among the most distant karyotype lineages and elucidates the need to define all karyotype variants and their geographical ranges in order to define the number of species of red brocket.

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