<p>A central theme in animal ecology is the study of the relationship between ecology and behavior. This dissertation demonstrates how ecological parameters, particularly food and weather variables, correlate with ranging, activity budget, and diet in Udzungwa red colobus monkeys (URC, <italic>Procolobus gordonorum</italic>), endemic to the Udzungwa Mountains, Tanzania. </p><p> From April 2009 - March 2010, four URC groups were habituated and studied in Mwanihana and Magombera Forests. During all-day follows, ranging, activity budget, and diet data were collected using GPS units and ten-minute scan samples of sustained activities. Food characteristics were assessed using transect and phenology surveys. Preliminary nutritional analyses were conducted on species-specific parts fed upon during October. I designed and employed novel methods for estimating ranging statistics which were compared with conventional methods.</p><p> Home range sizes were relatively small (8.8 - 20.8 ha). Home range size may relate to food species diversity and feeding selectivity for species-specific food parts. Variability in dietary composition was partly explained by plant phenology, forest composition, and selectivity differences among groups. URC primarily fed upon young leaves with higher fat content. Some non-nutritive items eaten may function as detoxifying agents. Data suggest that the URC dietary strategy involves nutrient balancing (i.e. maximizing energetic intake and nutrient acquisition while avoiding high concentrations of particular plant secondary compounds).</p><p> Mean daily travel distance (DTD) was 970 m, longer than in other red colobus taxa. DTD was shorter in October and November when temperatures were warmer and a high abundance of young growth became available. Young growth comprised the majority of all groups' diets in each sample period. When young growth abundances were highest, Magombera groups traveled shorter distances. One group's DTD did not differ seasonally and was significantly longer compared to other groups. This group may have traveled longer distances and spent less time resting in order to consume young growth in a habitat with lower young growth abundances. A correlation between time spent resting and temperature suggests behavioral prevention of hyperthermia. URC energetic strategies may involve balancing thermoregulation with maximizing energy intake. Conservation recommendations are discussed and include stricter forest protection.</p> / Dissertation

This study examined object permanence in Sumatran orangutans (Pongo abelii), Western lowland gorillas (Gorilla gorilla gorilla), and black-and-white-ruffed lemurs (Varecia variegata) at Zoo Atlanta. A literature review reveals two main issues with object permanence research in non-human primates. One of the issues is that it is difficult to make valid comparisons between different species because very few studies have been conducted using appropriate controls. Thus, one of the goals of this study was to conduct control trials for all tasks in the traditional object permanence test battery, in order to reliably assess and compare performance in the species under study. The second issue is concerned with the finding that all of the non-human primate species tested so far have failed one of the more difficult tasks in the test battery, namely the non-adjacent double invisible displacement task. It has been hypothesized that this performance limitation is a result of the manner in which the task is presented. Thus, the second goal of this study was to modify the existing methodology and present the task to gorillas and orangutans in locomotive space to see if performance improves. This is the first study to present this task to non-human primate species in locomotive space. This study found that orangutans were the only species to reliably pass most tasks in the traditional object permanence test battery. Black-and-white ruffed lemurs failed most visible and invisible displacement tasks. Owing to the small sample size of gorillas in this study, further research is required before any firm conclusions can be made about the ability of this species to solve visible and invisible displacement tasks in the traditional object permanence test battery. Presenting the boxes in locomotive space to gorillas and orangutans did not improve performance on the non-adjacent double invisible displacement task. Further research is required to resolve the question of whether this performance limitation is a result of the manner in which the task was presented.

Bibliography: leaves 231-[262] / xiii, 231, [112] leaves, 10 leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Entomology, 1984

Thesis (Ph. D.)--University of Pretoria, 2008. / Title from PDF title page (viewed on Nov. 11, 2008). Includes bibliographical references.

Les douleurs chroniques, d’origine inflammatoire, neuropathique ou incisionnelle, affectent environ 20 % de la population adulte et jusqu’à 50 % de la population âgée. Elles représentent ainsi un véritable enjeu de santé publique. Malgré l’existence de grandes familles d’analgésiques, les traitements restent souvent inefficaces. Cela est dû en grande partie à un manque de connaissances des mécanismes physiopathologiques de la douleur. Durant ma thèse, je me suis intéressée aux rôles et aux régulations de senseurs moléculaires de la douleur récemment mis en évidence: les canaux ioniques ASIC (« Acid Sensing Ion Channels »). Les ASIC forment une famille de canaux cationiques, excitateurs. Les canaux ASIC3, en particulier, sont présents dans les neurones sensoriels qui innervent la peau, les muscles, les viscères et les articulations. Ils sont activés par de faibles acidifications extracellulaires qui se produisent au cours de nombreux mécanismes physiopathologiques comme l’inflammation, l’ischémie, le développement tumoral, ou encore les lésions tissulaires consécutives, par exemple, à une chirurgie. Dans une première étude, nous avons montré que les canaux ASIC3 jouent un rôle primordial dans le développement des douleurs post-opératoires, notamment dans les douleurs posturales, proches des cas cliniques. A partir d’un modèle d’incision plantaire chez le rat, nous avons mis en évidence une surexpression des canaux ASIC3 dans les neurones sensoriels qui innervent la patte opérée. L’inhibition pharmacologique (toxine) et génique (siARN) d’ASIC3 in vivo réduit le comportement douloureux. Notre seconde étude a porté sur le canal ASIC3 humain, peu étudié jusqu’ici. J’ai démontré que ce canal possède une propriété originale et inductible qui lui confère une sensibilité, non seulement à l’acidification, mais également à l’alcalinisation extracellulaire. Cette sensibilité alcaline est une caractéristique intrinsèque du canal. Elle implique deux résidus arginine spécifiques à la protéine humaine et présents sur sa boucle extracellulaire. Le canal ASIC3 humain, en adaptant son activité à différents environnements de pH, pourrait ainsi participer à la régulation fine du potentiel de membrane et à la sensibilisation neuronale. Plus récemment, j’ai étudié la régulation du canal ASIC3 par des lipides inflammatoires et ses conséquences sur la douleur. De manière très intéressante, je démontre que la lysophosphatidylcholine (LPC), un lipide issu de la dégradation membranaire lors de processus inflammatoires, est un nouvel activateur du canal ASIC3 en conditions normales de pH. De plus, en synergie avec une acidose modérée (pH 7,0), la LPC et son analogue non métabolisable produisent une douleur spontanée chez les rats, qui est réduite en présence de toxine inhibitrice d’ASIC3. / Chronic, inflammatory, neuropathic, or incisional pain is affecting about 20 % of the adult population and up to 50 % of the elderly population. It thus represent a real public health issue. Despite the existence of large families of analgesics, treatments are often ineffective. This is due in large part to a lack of knowledge of the patho-physiological mechanisms of pain. During my PhD, I have been interested in the roles and regulation of molecular sensors of the pain recently highlighted: ion channels (ASICs "Acid Sensing Ion Channels "). ASICs constitute a family of excitatory cationic channels. The ASIC3 channels, in particular, are present in sensory neurons that innervate the skin, muscles, organs and joints. They are activated by low extracellular acidification occurring in many patho-physiological mechanisms such as inflammation, ischemia, tumor growth, or the subsequent tissue damage, for example, surgery. In a first study, we showed that ASIC3 channels play a crucial role in the development of post -operative pain, including postural pain, close to clinical cases. From a plantar incision model in rats, we demonstrated an over-expression of ASIC3 channels in sensory neurons innervating the operated hindpaw. Pharmacological inhibition (with toxin) and invalidation (siRNA) of ASIC3 in vivo reduce pain behavior. Our second study focused on the human ASIC3 channel, not yet extensively studied. I demonstrated that this channel has a unique and inducible property which gives it a sensitivity not only to acidification, but also to the extracellular alkalinization. This alkaline sensitivity is an intrinsic characteristic of the channel. It involves two specific arginine residues in the human channel that are present in its extracellular loop.Thus the human ASIC3 channel adapts its activity at different pH environments, and could participate in the fine regulation of membrane potential and neuronal sensitization. More recently, I have studied the regulation of ASIC3 channel by inflammatory lipids and there effects on pain. Interestingly, I showed that lysophosphatidylcholine (LPC), a lipid produced from the degradation of the membrane during inflammation, is a new activator of ASIC3 channel under normal pH conditions. Moreover, in synergy with moderate acidosis (pH 7.0), the LPC and its non-metabolizable analogue produce spontaneous pain in rats. This pain is reduced in the presence of the ASIC3 inhibitory toxin.

abstract: In today's world, unprecedented amounts of data of individual mobile objects have become more available due to advances in location aware technologies and services. Studying the spatio-temporal patterns, processes, and behavior of mobile objects is an important issue for extracting useful information and knowledge about mobile phenomena. Potential applications across a wide range of fields include urban and transportation planning, Location-Based Services, and logistics. This research is designed to contribute to the existing state-of-the-art in tracking and modeling mobile objects, specifically targeting three challenges in investigating spatio-temporal patterns and processes; 1) a lack of space-time analysis tools; 2) a lack of studies about empirical data analysis and context awareness of mobile objects; and 3) a lack of studies about how to evaluate and test agent-based models of complex mobile phenomena. Three studies are proposed to investigate these challenges; the first study develops an integrated data analysis toolkit for exploration of spatio-temporal patterns and processes of mobile objects; the second study investigates two movement behaviors, 1) theoretical random walks and 2) human movements in urban space collected by GPS; and, the third study contributes to the research challenge of evaluating the form and fit of Agent-Based Models of human movement in urban space. The main contribution of this work is the conceptualization and implementation of a Geographic Knowledge Discovery approach for extracting high-level knowledge from low-level datasets about mobile objects. This allows better understanding of space-time patterns and processes of mobile objects by revealing their complex movement behaviors, interactions, and collective behaviors. In detail, this research proposes a novel analytical framework that integrates time geography, trajectory data mining, and 3D volume visualization. In addition, a toolkit that utilizes the framework is developed and used for investigating theoretical and empirical datasets about mobile objects. The results showed that the framework and the toolkit demonstrate a great capability to identify and visualize clusters of various movement behaviors in space and time. / Dissertation/Thesis / Ph.D. Geography 2011

abstract: Despite years of effort, the field of conservation biology still struggles to incorporate theories of animal behavior. I introduce in Chapter I the issues surrounding the disconnect between behavioral ecology and conservation biology, and propose the use of behavioral knowledge in population viability analysis. In Chapter II, I develop a framework that uses three strategies for incorporating behavior into demographic models, outline the costs of each strategy through decision analysis, and build on previous work in behavioral ecology and demography. First, relevant behavioral mechanisms should be included in demographic models used for conservation decision-making. Second, I propose rapid behavioral assessment as a useful tool to approximate demographic rates through regression of demographic phenomena on observations of related behaviors. This technique provides behaviorally estimated parameters that may be applied to population viability analysis for use in management. Finally, behavioral indices can be used as warning signs of population decline. The proposed framework combines each strategy through decision analysis to provide quantitative rules that determine when incorporating aspects of conservation behavior may be beneficial to management. Chapter III applies this technique to estimate birthrate in a colony of California sea lions in the Gulf of California, Mexico. This study includes a cost analysis of the behavioral and traditional parameter estimation techniques. I then provide in Chapter IV practical recommendations for applying this framework to management programs along with general guidelines for the development of rapid behavioral assessment. / Dissertation/Thesis / M.S. Biology 2012

Estudos revelam que o extrato de orégano possui muitas funções na fisiologia animal. Resultados positivos de desempenho e produção foram encontrados em aves e suínos. Em ruminantes, alguns estudos foram conduzidos de forma a avaliar seus efeitos no rúmen, mas são inexistentes os que abordam seu efeito sobre o comportamento animal. No extrato de orégano, há predominância dos óleos essenciais carvacrol e timol. Este estudo objetivou avaliar as modificações no consumo e no comportamento ingestivo e social de novilhas recebendo diferentes doses de extrato de orégano (EO) na dieta. Foram utilizadas 34 novilhas holandesas mantidas em pastejo, com idade de 18,4 ± 4,2 meses e peso 424,2 ± 94,4 Kg, distribuídos em quatro tratamentos: C = controle - sem adição do extrato de orégano; EO 2,5 = 2,5 gramas; EO 5 = 5,0 gramas e EO 7,5 = 7,5 gramas/dia de extrato de orégano. O experimento teve duração de 77 dias, sendo os primeiros 21 de adaptação e constou de avaliações comportamentais focais feitas visualmente em um período de 8 horas, das 10:00 até às 18:00 horas (GMT -3:00). Os valores de consumo e as variáveis do comportamento ingestivo e mudanças posturais foram submetidas à análise de variância e regressão (PROC MIXED e PROC REG), adotou-se o nível 5% de significância. Consideraram-se os efeitos de dia, tratamento, interação tratamento e dia, as medidas realizadas no período pré-experimental foram utilizadas como covariáveis. As variáveis do comportamento social foram transformadas em respostas binárias e submetidas à análise logística (PROC LOG) pelo SAS Enterprise Guide 5.1. Não houve alteração no consumo e no comportamento ingestivo dos animais. Houve interação tratamento x dia para tempo gasto em decúbito, havendo um aumento linear no 46° dia após o início da suplementação. A chance de ocorrência de eventos de dominância aumentou em 1,12 vezes para cada 2,5 gramas de extrato de orégano adicionado à dieta (P=0,0496), enquanto a chance de ocorrência de eventos de submissão não foi alterada. A inclusão de até 7,5 gramas/dia de extrato de orégano não altera o consumo e comportamento ingestivo, porém aumenta os eventos de dominância e pode aumentar o tempo em decúbito de novilhas da raça Holandesa. / Oregano extract has many functions in animal’s physiology. Positive results on performance and production were found in poultry and swine. In ruminants, studies were conducted to evaluate the effects on the rumen metabolism, but few have addressed the effect on animal behavior. In the oregano extract, carvacrol and timol essential oils are prevalent. This study aimed to evaluate changes in ingestive and social behavior in heifers receiving oregano extract (OE) in the diet. Thirty-four Holstein heifers kept in grazing, aged between 18.4 ± 4.2 months and with 424.2 ± 94.4 kg BW were distributed into four treatments: C = control - without addition of oregano extract; OE 2.5 = 2.5 grams; 5 OE = 5.0 grams and OE 7.5 = 7.5 grams/day of oregano extract. The experiment lasted 77 days, with 21 days of adaptation. Behavior evaluation was performed through visual and focal observations of the animals during 8 hours for the day, from 10:00 to 18:00 h (GMT -3:00). Data about intake and ingestive behavior and change in posture were submitted to analysis of variance and regression (PROC MIXED e PROC REG), significance was settled at 0.05. Testing the effects of day, treatment, interaction between treatment and day, and the pre experimental measurements were used for adjustment by covariance. The variables of social behavior were transformed into binary answers and submitted to logistic regression (PROC LOGISTIC) using the SAS Enterprise Guide 5.1. No differences in the feed intake and ingestive behavior of the heifers were detected between treatments. etected. On the 46° day after the beginning of OE supplementation, time spent lying increased with OE addition into the diet. The risk of occurrence of dominance events increased by 1.12 times for each 2.5 grams of the oregano extract added in the diet (P=0.0496), while OE did not change the risk of occurrence of submission events. Inclusion of up to 7.5 grams/day of oregano extract does not change feed intake and ingestive behavior, however increases the chance of occurrence of dominance events and may increase the time spent lying of Holstein heifers.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O turismo vem sendo considerado como solução de problemas econômicos em muitas comunidades de baixa renda, mas também pode ser causador de impactos negativos. O condicionamento de animais selvagens através da alimentação artificial facilita o trabalho dos operadores de turismo de natureza ao criar mais situações de encontro e diminuir as distâncias entre os turistas e esses animais, mas casos ao redor do mundo demonstram numerosos impactos negativos resultantes de tais atividades. No estado do Amazonas, Brasil, cinco casos de atividade turística onde botos-da-Amazônia (Inia geoffrensis) foram condicionados ao contato humano através da alimentação articial vêm ocorrendo, sendo o caso do Parque Nacional de Anavilhanas (PNA), em Novo Airão (NA), o precursor. Assim, os objetivos da presente tese são: descrever os casos de condicionamento de botos como atração turística no estado do Amazonas, avaliar se as atividades turísticas de alimentação artificial influenciam a agressividade e o comportamento social dos botos condicionados do PNA, produzir uma avaliação acurada da percepção da comunidade local de NA com relação aos possíveis impactos socioeconômicos desta atividade turística, acessar a percepção dos pescadores locais quanto às interações entre cetáceos (incluindo o tucuxi, Sotalia fluviatilis) e atividades de pesca e os impactos do condicionamento de botos nessas interações, na região de NA e conduzir uma análise das expectativas prévias e experiências realizadas pelos turistas participantes das atividades de interação com os botos em NA, avaliando também sua percepção geral sobre este tipo de turismo, em especial com relação à sua proximidade com os animais. Os métodos utilizados para a coleta dos dados foram: entrevistas etnográficas semi-estruturadas, observação participante, questionários auto-aplicáveis e métodos de amostragem comportamental. Os resultados demonstraram que as atividades baseadas no condicionamento geram vários impactos negativos. Pode-se concluir que a atividade turística baseada no condicionamento de botos através da alimentação artificial: tem se dispersado pelo estado do Amazonas ao longo dos últimos anos, altera o comportamento social e causa o aumento da competição entre os botos condicionados em NA, apesar de gerar empatia pelo boto em parte da população de Novo Airão, é percebida pelos moradores como gerando poucos benefícios econômicos, sendo que a maioria se sente excluída do compartilhamento de benefícios gerados pela mesma, aparentemente não resulta em uma grande mudança na percepção negativa dos botos por parte dos pescadores, que também se percebem como estando excluídos do compartilhamento de benefícios gerados pela atividade e geram um alto grau de satisfação nos turistas participantes e atendem às atuais expectativas dos turistas, mas através de atividades invasivas que provavelmente disseminam a ideia de que condicionar animais silvestres ao contato humano através da alimentação artificial é correto. Assim, possivelmente a atividade em questão não está em completo acordo com as leis brasileiras, conceitos de ecoturismo e funções das unidades de conservação. Propostas de manejo para superar a controversa questão relacionada à alimentação artificial como prática turística e fortalecimento de práticas menos negativamente impactantes de caráter participativo para NA são sugeridas. / Tourism has been considered the solution to economic problems in many low income communities, however, tourism can also cause negative impacts. Conditioning wild animals through artificial feeding facilitates the work of nature tourism operators by creating more encounters with and decreasing the distances between tourists and these animals, but examples around the world show numerous negative impacts resulting from such activities. In Amazonas State, Brazil, there are five current cases of tourism activities in which botos (Inia geoffrensis) are being conditioned to human contact through artificial feeding, being the case of the Anavilhanas National Park (ANP), in Novo Airão (NA), the pioneer. Therefore, the aims of the present work are to describe these cases of conditioning of botos as a tourism attraction in Amazonas State, to evaluate the influence of this activity on the aggressiveness and social behavior of the conditioned botos in the ANP, to evaluate the perception of the NA community in relation to the possible socioeconomic impacts resulting from this tourism, to evaluate the perception of the fishermen from NA regarding to interactions with the river dolphins and the impact of this tourism on those interactions, and to evaluate the prior expectations, general perception and experiences of the tourists participating in the interactions with botos in the ANP. The methods utilized for data collection were as follows: semi-structured ethnographic interviews, participant observation, self-completed questionnaires and behavioral sampling methods. Results showed that the activities based on conditioning cause numerous negative impacts. It is concluded that this kind of tourism is dispersing through the Amazonas State. Conditioning causes an increase in the competition among the botos and deeply alters their social behavior. Broadly speaking, the population of NA perceives themselves as being excluded from the sharing of the economic benefits resulting from this tourist activity. This activity apparently do not cause a change in the local fishermen negative perceptions about the botos, and they also perceives themselves as being excluded from the sharing of economic benefits. Furthermore, the degree of satisfaction achieved by the tourists in NA during these activities is very high, but such satisfaction is reached by participating in invasive activities that disseminate the idea that conditioning wild animals through artificial feeding is correct. Tourist activities related to boto conditioning are possibly not in complete agreement with the functions of conservation units, ecotourism concepts and Brazilian Legislation. Management proposals aiming to achieve less negatively impacting activities are proposed, such as the implementation of a tourism activity not based on artificial feeding/conditioning and an education/interpretation program to provide more accurate information to tourists about the natural behavior of the botos to provide them with realistic expectations prior to participating in less-invasive dolphin-watching activities

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No. of bitstreams: 1 DISS_2014_Gianni Paolo Motta Rebuffo.pdf: 1617331 bytes, checksum: 27a960e1f466b9883e8eb6a13a881887 (MD5) Previous issue date: 2014-04-22 / CAPES / A pesquisa foi desenvolvida com base em dois experimentos de curto prazo realizados no outono e na primavera do ano 2010 e um terceiro de um ano agrícola, objetivando avaliar os efeitos da intensidade de desfolhação na produção de forragens, no desempenho animal e comportamento ingestivo de vacas Holandesas em duas estações do ano, outono e primavera. Os experimentos foram desenvolvidos na Estação Experimental Mario Antonio Cassinoni (EEMAC) Paysandú-Uruguai pertencente à Faculdade de Agronomia – Universidad de La República. O primeiro experimento foi conduzido com objetivo de avaliar o comportamento ingestivo, composição química da forragem selecionada e a produção e composição do leite de vacas holandesas em pastos com diferentes ofertas de forragem no começo do outono. Foram utilizadas 36 vacas Holandesas com parições de outono e 1410 dias em lactação. Os animais foram alocados em blocos, considerando: a data de parição, o peso vivo e o escore corporal. Os tratamentos foram constituídos por três ofertas de forragem, sendo: alta (38,4 kg MS/vaca/dia), média (30,3 kg MS/vaca/dia) e baixa (26,8 kg MS/vaca/dia), por um período de 56 dias. Entre as ordenhas da manhã, às 7 horas e 30 minutos, e da tarde, às 14 horas e 30 minutos, os animais tiveram acesso irrestrito ao pasto de segundo ano de produção com composição botânica de 58% de Festuca arundinacea, 20% Trifolium repens, 12% de material morto e 10% de plantas invasoras. Após a ordenha vespertina os animais foram suplementados em baias individuais com 3 Kg/vaca/dia de silagem de Festuca arundinacea e Trifolium repens e 5,5 Kg/vaca de suplemento concentrado em uma relação 35:65 volumoso/concentrado com base na matéria seca (PB=171±10 g/Kg MS, FDN=400±20 g/Kg MS). A produção de leite foi mensurada diariamente e de forma individual em ambas as ordenhas. Semanalmente foram realizadas amostragens individuais de leite para a determinação de gordura e proteína em leite. As informações de comportamento animal foram obtidas a partir de observações visuais e por registradores de movimentos mandibulares (Grazing Recorders ®). A composição química da forragem selecionada foi obtida pelo método de pastejo simulado. Foi utilizado o delineamento em blocos casualizados, sendo realizados análise de variância dos dados, e o teste de Tukey ao nível de 5% de significância. Os tratamentos com ofertas de forragem alta e média tiveram maior produção de leite (P<0.05) quando comparado ao tratamento de oferta de forragem baixa, sem apresentar diferenças significativas entre eles. Não foram observadas diferenças significativas na produção de gordura (934 g/vaca/dia), porcentagem de gordura (3,71%), e de proteína (3,16%). Todavia, verificou diferenças significativas (P<0.05) na produção de proteína do leite, apresentado diferenças significativas entre os manejos de oferta média e baixa. O tempo de pastejo foi afetado pela oferta de forragem (P<0.05) com valores médios de 369,1±7,1; 317,0±7,0; e 335,1±7,2 minutos/dia, para os manejos de alta, média e baixa oferta de forragem respectivamente. Foi verificada uma diferença significativa na taxa de bocado com valores de 64±2,0, Média 51±2,0, 60±1,9, para alta, média e baixa oferta de forragem, respectivamente. Não foram observadas diferenças significativas (P>0.05) no conteúdo de PB da forragem selecionada, registrando um valor médio de 17,9%. Todavia, verificou-se diferença (P<0.05) para os teores de FDN do pasto, apresentando um maior teor no manejo de oferta baixa. Pode ser concluído que para condições de pastejo com ofertas de forragem inferiores aos 26,8 Kg de MS/vaca/dia o desempenho animal é reduzido. No segundo capitulo avaliou se na primavera seguindo a mesma metodologia do capitulo um. Foram utilizadas 36 vacas Holandesas com parições de primavera e 16±11 dias em lactação. Os animais foram alocados em blocos, considerando: a data de parição, o peso vivo e o escore corporal. Os tratamentos foram constituídos por três ofertas de forragem, sendo: alta (49,8 KgMS/vaca/dia), Média (33,7 KgMS/vaca/dia) e baixa (27,6 KgMS/vaca/dia) por um período de 56 dias. Entre as ordenhas da manhã, às 7 horas e 30 minutos, e da tarde, às 14 horas e 30 minutos, os animais tiveram acesso irrestrito a pasto de segundo ano de produção com composição botânica de 56% de Festuca arundinacea, 37% Trifolium repens, contentado 5% de material morto e 2% de plantas invasoras, sendo suplementadas com 2 Kg MS/vaca de um suplemento energético em cada ordenha (PB:1811 g/Kg MS, FDN 19110 g/Kg MS). A produção de leite foi mensurada diariamente e de forma individual em ambas as ordenhas. Semanalmente foram realizadas amostragens individuais de leite para a determinação das teores de gordura e proteína em leite. As informações de comportamento animal foram obtidas a partir de observações visuais e por registradores de movimentos mandibulares (Grazing Recorders ®). A composição química da forragem selecionada foi obtida pelo método de pastejo simulado. Foi utilizado o delineamento em blocos casualizados, sendo os dados submetidos a análise de variância e o teste de Tukey ao nível de 5% de significância. Não foram encontradas diferenças significativas nos teores de %PB, %FDN e %FDA da forragem colhida pelos animais, com valores médios de 24,8±1,17; 37,9±1,44 e 22,4±1%, respectivamente. Foram verificadas diferenças significativas no comportamento ingestivo nos distintos manejos (P<0.05). O manejo de oferta de forragem média apresentou a maior produção de leite (P<0.05) (30,56±0,29), seguida do manejo de oferta baixa (29,42±0,28) e o manejo de oferta alta de forragem (27,14±0,32). Foram observadas diferenças significativas nos percentuais de proteína e gordura no leite nos tratamentos (P<0.05). As diferenças observadas no desempenho animal foram consequência das diferentes estratégias de seleção e colheita de pasto dos animais para maximizar a taxa de consumo nos diferentes ambientes de pastejo criados pela consequente oferta de pasto. O terceiro experimento foi conduzido com o objetivo de avaliar três tratamentos de ofertas de forragem por meio de mudanças na intensidade de desfolhação ao longo do segundo ano de produção de um pasto consorciado com Festuca arundinacea, e Trifolium repens, utilizando vacas leiteiras da raça Holandesa em um método de pastejo rotativo. No outono com ofertas de forragem alta de 38,4 kg MS/vaca/dia, média de 30,3 kg MS/vaca/dia e baixa de 26,8 kg MS/vaca/dia. Na primavera por três ofertas de forragem, sendo: Alta (49,8 KgMS/vaca/dia), Média (33,7 KgMS/vaca/dia) e Baixa (27,6 KgMS/vaca/dia). No inverno e no verão os piquetes foram manejados com pastejo rotativo e um critério de ingresso ao pasto baseado em uma altura pré pastejo de 18 a 20 centímetros, mantendo a altura de saída do pastejo de 7 centímetros, 9 centímetros e 11 centímetros para os manejos de oferta de forragem baixa, média e alta respectivamente. O experimento foi realizado na Estação Experimental Mario Antonio Cassinoni (EEMAC) Paysandú-Uruguai pertencente à Faculdade de Agronomia – Universidad de La República por um período de um ano a partir de janeiro de 2010. Uma vez por semana ao longo do ano foi determinada a taxa de crescimento do pasto e o acúmulo total de forragem. Uma vez por estação foi determinada a composição botânica dos pastos. A produção de leite por hectare foi determinada de forma individual no período de ocupação dos animais nos piquetes. A taxa de lotação foi calculada a partir do número de animais em pastejo e do tempo de ocupação em cada ciclo de pastejo. Foi utilizado o delineamento em blocos casualizados com três tratamentos e quatro blocos, sendo realizados análise de variância dos dados, e o teste de Tukey ao nível de 5% de significância. Não foram observadas diferenças significativas (P>0.05) na taxa de crescimento médio anual entre os manejos de alta (40,034,41 Kg MS/ha/dia), média (45,394,41 Kg MS/ha/dia) e baixa (42,164,41 Kg MS/ha/dia) oferta de forragem. Não foram verificadas diferenças significativas (P>0.05) no acúmulo líquido de forragem anual entre os manejos de alta (14620571 Kg MS/ha/ano), média (16576571 Kg MS/ha/ano) e baixa (15373571 Kg MS/ha/ano) oferta de forragem. Comportamento similar foi observado (P>0.05) para a composição botânica do pasto entre os manejos de oferta de forragem. Também não foram registradas diferenças significativas (P>0.05) para a taxa de lotação média anual entre os manejos de alta (1,710,08 animais/ha), média (1,870,08 animais/ha) e baixa (1,730,08 animais/ha) oferta de forragem. Contudo, foram verificadas diferenças significativas (P<0.05) na taxa de acumulo de forragem, produção total de biomassa e taxa de lotação animal dentro das estações do ano para os distintos manejos de oferta de forragem. Foram observadas diferenças significativas (P<0.05) na produção total anual de leite por hectare entre os manejos de alta (11542290b L/ha/ano), média (13256290a L/ha/ano) e baixa (11392290a L/ha/ano) oferta de forragem. Conclui-se que o manejo do pasto para uma oferta média de forragem ao longo do ano proporciona maior produção de leite por hectare. A produção individual de leite em vacas leiteiras varia em função da oferta de forragem existindo interações com a estação do ano, onde a produção de leite por vacas com parição no outono é influenciada negativamente com ofertas inferiores aos 26,8 Kg de MS/vaca/dia. Na primavera o desempenho animal apresentou um comportamento quadrático, onde o maior desempenho encontra se em ofertas de forragem 33,7 Kg de MS/vaca/dia. As ofertas de forragem afetaram a taxa de crescimento e a taxa de lotação nas distintas estações do ano, onde a maior produtividade de leite por hectare por ano foi obtida no manejo de oferta média de forragem ao manter alta taxa de crescimento do pasto e alta taxa de lotação em todas as estações do ano. / The present research was developed based on two short term experiments carried out in autumn spring of 2010 and one in the hole productive year of 2010, whit the objective of study the effects of grazing intensity in animal performance and their effects on animal grazing behavior. The experiments were carried out in the Experimental Station of de Agronomy Faculty of Uruguay. The first experiment was carried out with the objective of evaluate animal behavior, forage selection, and animal performance in Holstein dairy cows by changing forage mass offerduring early lactation on early autumn. The animals were blocked by calving date (27/3 10), live weight (527± 67 Kg), body condition score (2,790,31) and randomly distributed in three treatments: Hi (OA: 38.4 kg DM/cow.day-1), Medium (OM: 30.3 kg DM/cow.day-1) and Low (OB: 26.8 kg DM/cow.day-1) forage mass offer for a 56 days period. The animals grazed during the morning from 7:30 to 14:30 hours between the morning and evening milk in individual paddocks for each treatment in a second year perennial pasture whit a botanical composition of 58% of Festuca arundinacea, 20% od Trifolium repens, 12% of death forage and 10% of weeds. After the evening milk the animals were individually supplemented whit 5.5 Kg of DM per cow of a total mixed ration with a concentrate : voluptuous relation of 65:35 in dry matter bases (CP=17,1±1,0%, NDF=40,0%). Diary milk production was measured in each milk, individual samples of all animals were taken weakly, for milk fat and protein determination. Animal grazing behavior was measures whit Grazing Recorders® during the last 3 days in each paddock in three animals per treatment. During these days it was determined pasture selection by Hand clipping techniques. The experimental design was completely random blocks, all the results were submitted to a variance analysis applying the Tukey Krammer test whit a 5% of probability of error. During the experimental period the OA and OM treatments had a superior milk production (P<0.05) that the OB treatment whit no statistic differences between them (26,0±0,4 vs. 23,8±0,4 L/cow/day). No statistic differences were obtained in Milk fat percentage (mean: 3,71±0,09%), milk protein percentage (mean: 3,16±0,05%) nor total fat production (mean: 934±46 g/cow/day). Significant differences between treatments were observed for total protein production (820±30, 846±29, and 718±33 g/cow/day) for OA, OM and OB respectively. There were no significant differences for CP values for the forage selected between treatments (mean:17,90,71%), but there were observed significant differences for NDF percentages (44,8±0,79, 47,0±0,82 and 49,4±0,80 (P<0.05) for AO OM and OB treatments respectively. There were observed significant differences (P<0.05) between treatments on grazing time (369,1±7,1; 317,0±7,0; 335,1±7,2 minutes/day) for OA OM and OB, such as on the bite rate (64 ± 2,0; 51 ± 2,0; 60 ± 1,9 bites/minute) or OA OM and OB. During the experimental period the OB treatment had a lower milk production, that could be explained by a inferior quality of the diet selected expressed by a higher NDF value and a diminish of grazing time in comparison with the OA treatment. Under grazing conditions during the autumn forage mass offer under 26,8 KgDM/cow/day, animal performance is negatively affected. The second experiment was carried out during the spring with the same objectives as the experiment one. There were used 36 Holstein dairy cows whit spring calving and 1611 days in lactation. The animals were blocked by calving date, live weight, body condition score and randomly distributed in three treatments: Hi(OA: 49.8 kg DM/cow.day-1), Medium (OM: 33.7 kg DM/cow.day-1) and Low (OB: 27,6 kg DM/cow.day-1) forage mass offer for a 56 days period. The animals grazed during the morning from 7:30 to 14:30 hours between the morning and evening milk and from 17:00 untill 4:30 hours in individual paddocks for each treatment in a second year perennial pasture whit a botanical composition of 56% of Festuca arundinacea, 37% of Trifolium repens, 5% of death forage. Animals were supplemented whit 2 KgDM/cow of a concentrate supplement during each milk (CP:18,11 %; NDF:19,11,0 %). Diary milk production was measured on each milk, individual milk samples were taken weakly, for milk fat and protein determination. Animal grazing behavior was measures whit Grazing Recorders®. During this days it was was determined forage selection by Hand clipping techniques. The experimental design was completely random blocks, all the results were submitted to a variance analysis applying the Tukey Krammer test whit a 5% of probability of error. There were no significative differences on the selected forage by the treatments (CP: 24,8±1,17; NDF:37,9±1,44 and ADF:22,4±1 %. There were observed significant differences (P<0.05) between treatments on grazing behavior, which conducted in forage dry matter intake differences between treatment. During the experiment the Medium forage offer treatment presented the highest milk production (P<0.05) (30,56±0,29), followed by the low forage offer treatment (29,42±0,28) and the hi forage offer treatment (27,14±0,32). Statistical differences were bserved in milk solid values (P<0.05). The animal performance differences between treatments were caused by the different forage selection strategies used by the animals during grazing, trying to maximize intake rate under different grazing environments created by the treatments. The third experiment was conducted an experiment whit the objective of evaluate three forage mass offer treatments by changing grazing intensity whit Holstein dairy cows in a second year perennial pasture of Festuca arundinacea, and Trifolium repens, for a one year period. The experiment was carried out in the Experimental Station of de Agronomy Faculty of Uruguay in 2010. Once a week forage growth rate, a total biomass production was measured. The botanical composition was measured once a month in each treatment. Total milk production per hectare was determined by individual milk of all animals during the stoking period. Stocking rate was calculated using the number of animals in the total area and the time spent grazing. The experimental design was completely random blocks, all the results were submitted to a variance analysis applying the Tukey test whit a 5% of probability of error. There were no statistical differences (P>0.05) in the annual forage growth rate (40,034,41; 45,394,4; 42,164,41 KgDM/ha/day), for hi, medium and low forage mass offer. There were no statistical differences (P>0.05) in the total annual biomass production (14620571; 16576571; 15373571 KgDM/ha/year), for hi, medium and low forage mass offer. There were no statistical differences (P>0.05) in the annual stocking rate (1,710,08; 1,870,08; 1,730,08 animals/hectare), for hi, medium and low forage mass offer. No statistical differences (P>0.05) were observes in the botanical composition between treatments. Seasonal variation in forage growth rate, forage biomass accumulation and stocking rate, affected the total milk production per hectare per year (P<0.05), where the medium forage mass offer treatment presented the highest milk production (13256290 L/hectare/year) not presenting statistical differences between de hi (11542290 L/hectare/year) and low (11392290 L/hectare/year) forage mass offer. A medium forage offer during the whole year grants the best productive performance per hectare. Animal performance in dairy cows diverges with forage mass offer, existing an interaction between seasons, where during the attumn presented negative correlations with forage mass offer below 26.8 Kg of DM/cow/day. During the spring there was a quadratic relation between forage mass offer and animal performance, were the greatest animal performance was obtained with forage mass offers of 33.7 Kg of DM/cow/day. Seasonal variation in forage growth rate, and stocking rate were affected by forage mass offer, where the medium forage mass offer treatment presented the highest milk production since it presented also a high forage growth rate and a high stocking rate along the houle year.