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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

Livestock Foraging Behavior In Response To Sequence and Interactions Among Alkaloids, Tannins, and Saponins

Jensen, Tiffanny L. 01 May 2012 (has links)
The influence of primary compounds (energy, protein, minerals, and vitamins) in animal nutrition and foraging behavior has been studied for years. The roles of secondary compounds (terpenes, alkaloids, and phenolic compounds) are equally important, yet they have been ignored until recently. Where secondary compounds were once considered toxic by-products of plant metabolism, we now know they are actively involved in plant and animal behavior, health, and productivity. Though often appreciated historically for their negative impacts on food intake and animal production, we are becoming increasingly aware of their beneficial roles in the health of plants, animals, and humans. When animals can ingest an array of plants that contain different kinds and amounts of secondary compounds, they can mix different foods in their diet to better use both primary and secondary compounds, enhancing their health and production, as well as economic and ecological characteristics of landscapes. Endophyte-infected tall fescue contains the alkaloids perlolidine, perloline, ergotamine, and ergovaline, which are all steroidal or protein-like in nature. Tannins and saponins have a high affinity for binding proteins and lipids in the gastro-intestinal tract of animals, and facilitating their excretion from the body. These findings suggest animals may increase their use of forages with alkaloids when they are also provided forages that contain tannins or saponins. The sequence in which forages with different secondary compounds are ingested may influence any potential interactions because different compounds have different residence times in the gastrointestinal tract. I tested the hypothesis that cattle and sheep foraging behavior is influenced by eating different combinations of forages containing secondary compounds in different sequences. In pen and pasture trials, I showed that 1) cattle grazing pastures of endophyte-infected tall fescue (TF) grazed more often on TF when first allowed to graze legumes containing either tannins or saponins, and they grazed TF much more when they first grazed legumes as opposed to the reverse sequence; 2) sheep fed basal diets high in the alkaloid ergotamine d tartrate (EDT) ate more when supplemented with food containing either tannins or saponins, but in contrast to the trials on pasture with cattle, their behavior was not dramatically influenced by sequence; 3) cattle fed fresh cut endophyte-infected tall fescue were not influenced by the addition of tannin to their drinking water, as tannins limited both water and forage intake; 4) sheep fed food containing EDT ate more when supplemented with food containing tannins or when given a choice of foods containing tannins or saponins, than sheep supplemented with food containing saponins or no additional secondary compound. Results from these studies suggest that secondary compounds interact with one another to influence foraging behavior, and that sequence of food ingestion can be influential when animals graze on pastures.
432

Por que onça-parda (Puma concolor) ataca as criações de algumas propriedades e não de outras? /

Campos, Mariana Dias de. January 2019 (has links)
Orientador: Carlos Camargo Alberts / Banca: Fernando Frei / Banca: Beatriz de Mello Beisiegel / Resumo: Entre os grupos de vertebrados, os mamíferos carnívoros têm sido utilizados como espécies-alvo em diversos projetos ambientais. Atualmente, apresentam populações pequenas e muitas vezes em declínio classificados com algum grau de ameaça de extinção, consequência das alterações na paisagem causadas pelas atividades humanas. No Brasil, atualmente, a maior causa da diminuição das populações de mamíferos carnívoros é a redução ou perda de habitat ocasionada pela expansão agrícola, pecuária, exploração mineral e urbanização. A predação por onças-pardas tem sido documentada em diversas regiões e, como consequência, a perseguição a esses animais é fortemente observada. A fim de identificar os fatores que poderiam estar associados às predações aos rebanhos domésticos por onças-pardas no oeste do Estado de São Paulo, realizamos entrevistas com produtores rurais, utilizando para isso questionários semiestruturados, abordando características das propriedades, do manejo e da paisagem. Realizamos 54 entrevistas e identificamos propriedades que passaram por eventos de predação nos últimos oito anos. Bovino foi o grupo de animais mais frequentemente predado. Através da Regressão Logística, foi possível obter um modelo de previsão de ataques com 83% de concordância entre estimado e observado, onde o número de suínos e a distância do rio para a sede, presentes em cada propriedade, foram positivamente relacionados aos casos de predação. Através das análises das Redes Neurais Artificiais, foi possível especular a presença de um ciclo predador-presa ocorrendo entre o puma concolor e uma presa ainda desconhecida. Práticas de manejo adequadas podem reduzir significativamente as perdas de animais domésticos e assim reduzir possíveis conflitos humanos com predadores selvagens / Abstract: Among the vertebrate groups, carnivorous mammals have been used as target species in several environmental projects. Currently they present small and often declining populations, classified as with some degree of threat of extinction, consequence of the changes in landscape caused by human activities. In Brazil, the major current cause of the decline in carnivorous mammal populations is the reduction or loss of habitat caused by agricultural expansion, livestock farming, mineral exploration, and urbanization. Predation by pumas has been documented in several regions and as a consequence the chase of these animals is strongly observed. In order to identify the factors that could be linked to domestic herds predation by pumas in the west of São Paulo State, we conducted interviews with rural producers, using semi-structured questionnaires, addressing properties characteristics, management and landscape. We have made 54 interviews and identified some rural properties that experienced predation events in the last eight years. Bovines was the group most frequently predated. Throught the Logistic Regression, it was possible to get a model of prediction of attacks with 83% of agreement between estimated and observed, where the number of swines and the distance from the river to the principal house present in each property was positively related to predation cases. Through the analysis of Artificial Neural Networks it was possible to speculate the presence of a predator-prey cycle occurring between the puma concolor and a prey still unknown. Appropriate management practices can significantly reduce the losses of domestic animals and thus reduce possible human conflicts with wild predators / Mestre
433

The Economic Role of Range Livestock Production in Kasungu Agricultural Development Division (KADD), Malawi

Phiri, Phillip H. W. 01 May 1997 (has links)
This study was conducted to determine the effects of seas on and auction and produce marketing systems on prices received by farmers for livestock sales and the effect of price on cattle numbers sold in KADD. Livestock population, carrying capacity, and stocking rate were estimated. Data were analyzed using pie charts, regression methods, and analysis of variance. There was no significant difference (P=.06) between cattle prices per kilogram during the wet season and after harvest. During the wet season, significantly more cattle were sold than after harvest (P< .001) to purchase food and farm inputs, and pay school fees and medical bills. Market price was only a secondary factor. Carrying capacity and stocking rate were estimated at 15.00 kg metabolic mass per hectare and 12.00 kg metabolic mass per hectare, respectively. Most households primarily sold male cattle because females are retained for breeding.
434

Behavioral Characteristics Affect Habitat Selection of Domestic Ruminants

Scott, Cody B. 01 May 1995 (has links)
I evaluated some of the factors affecting livestock distribution by conducting experimental (Chapters II and III) and observational (Chapter IV) studies. In Chapter II, I described the effect of locations of familiar foods and social interactions on choice of feeding location by lambs. Lambs were exposed to a pasture as subgroups of strangers and companions with different dietary habits (i.e., three lambs that preferred milo with three lambs that preferred wheat). Milo was placed on one end and wheat on the other, about 100 m apart. Strangers typically fed in different locations, reflecting dietary preferences. Conversely, companions fed in both single subgroups and in separate subgroups because both social interactions and dietary preferences affected choice of feeding location. The objective of Chapter III was to evaluate the effect of experience with a pasture on choice of feeding location. Lambs with different levels of familiarity with the pasture were exposed as subgroups with different dietary habits. Lambs familiar with the pasture typically fed in separate locations, reflecting dietary preferences. Lambs naive to the pasture always fed in one subgroup and consumed both foods because social interactions overrode dietary preferences. Results in Chapter IV describe cattle observations on a 1,030-ha grazing allotment. Cattle home ranges were similar in location (i.e., site fidelity) between 1990 and 1991, even though home ranges increased in size and (or) shifted in location in response to water availability. Moreover, forage availability did not account for changes in home range size or location. Site fidelity probably developed because of experiences early in life while foraging with mother and (or) peers. Managers may be able to improve distribution by manipulating foraging experiences. Placing familiar foods/supplements in underutilized areas, controlling the amount of experience livestock have with different habitat types, and culling animals that spend a disproportionate amount of time in riparian zones may improve · distribution. Herding could also improve distribution. Herding integrates social interactions and experience with foods by controlling the exposure of social groups to particular foods and habitats. Nevertheless, livestock may still spend considerable time in riparian zones unless other watering points are available.
435

Some of the Relationships Between Livestock Grazing and Duck Nesting in the Saltgrass Vegetation Type in Utah

Murdy, Horatio W. 01 May 1953 (has links)
Little is known of the relationships between livestock grazlng and duck nesting. This dearth of information occurs in spite of the fact that an understanding of these relationshipships is necessary in order to evaluate duck production on range land, and to formulate grazing policies for lands devoted to the production of ducks. Recognizing the need for information on this subject, the Utah Cooperative Wlldllfe Research Unit and the Wildlife Management Institute jointly sponsored a study, during 1948-1949, of livestock grazing-duck nesting relationships in the saltgrass vegetation type in northern Utah. The study was financed by the Institute and supervised by the research unit. The writer was employed to make the study. This thesis presents his findings. The saltgrass type was chosen for study because it is an extensive vegetetlon type on the wet, alkaline lands of the Great Basin. It occurs at the duck-producing river deltas and marshes on land which is too alkaline for agriculture and is therefore used for grazing. Such lands are low enough in monetary value to permit their purchase for waterfowl management areas.
436

Depth images\' processing to improve the performance of sows through early detection of lameness and changes in body condition score / Processamento de imagens em profundidade para melhora do desempenho de matrizes suínas por meio da detecção precoce de claudicação e de alterações no escore de condição corporal

Condotta, Isabella Cardoso Ferreira da Silva 07 June 2019 (has links)
The observation, control and the maintenance of the physical condition of sows in acceptable levels are critical to maintain the animal welfare and production in appropriate standards. Lameness causes pain making locomotion difficult. However, lameness is a common disorder in sows that causes negative impacts in both welfare and production. Since the animals that demonstrate this problem, have a smaller number of born-alive piglets, fewer gestation per year and are removed from the herd at a younger age than the ideal. In addition, it is industry practice to limit feed sows to ensure that they remain at an ideal condition score. It is known that, during gestation, each sow should receive a different amount of food according to its body condition. Underweight animals have nutritional deficiency and lower number of piglets per litter. On the other hand, overweight sows have an abnormal development of mammary glands, reducing the amount of milk produced during lactation, causing economic losses. However, moving sows to group gestation makes it difficult to monitor condition score in gestating sows. Both the detection of lameness and the classification of body condition are currently assessed using subjective methods, which is time consuming and difficult to accurately complete. Therefore, the early recognition of animals that present physical condition outside the standards is important to prevent production losses caused by both the aggravation of the conditions presented and the impact on the animals\' welfare. The objective of this project is to obtain three characteristics (body condition score, mass and backfat thickness) through depth images, that proved to be effective on the acquisition of these features in other animals (boars and cows). The second objective is to develop a method for early detection of lameness using the kinematic approach, that has been generating good results and which difficulties have the potential to be reduced by using depth images instead of the method of reflective markers currently used. To predict body condition, a multiple linear regression was obtained using the minor axis of the ellipse fitted around sow\'s body, the width at shoulders, and the angle, of the last rib\'s curvature. To predict backfat, a multiple linear regression was performed using the height of last rib\'s curvature, the perimeter of sow\'s body, the major axis of the ellipse fitted around sow\'s body, the length from snout to rump, and the predicted body condition score. It was possible to obtain the body mass with a simple linear regression using the projected volume of the sows\' body. For lameness detection, three models presented the best accuracy (76.9%): linear discriminant analysis, fine 1-nearest neighbor, and weighted 10-nearest neighbors. The input variables used on the models were obtained from depth videos (number, time, and length of steps for each of the four regions analyzed - left and right shoulders and left and right hips; total walk time; and number of local maxima for head region). As a result of these studies, it has been demonstrated that a depth camera can be used to automate the weight, condition score, backfat thickness, and lameness acquisition/detection in gestating and lactating sows. / A observação, o controle e a manutenção das condições físicas de matrizes suínas em níveis aceitáveis são fundamentais para manter o bem-estar animal e a produção em padrões adequados. A claudicação causa dor e dificuldade de locomoção e, no entanto, é uma desordem comum em matrizes suínas que, além do impacto negativo no bem-estar, gera, também, grandes impactos na produção, uma vez que os animais que demonstram esse problema, apresentam um menor número de leitões nascidos vivos, menor número de partos por ano e são removidas do rebanho a uma idade mais jovem do que a ideal. Sabe-se, ainda, que, durante a gestação, cada matriz deve receber uma quantidade de ração diferenciada de acordo com sua condição corporal. Animais abaixo do peso apresentam deficiência nutricional e menor número de leitões nascidos por ninhada. Já as matrizes com excesso de peso apresentam um desenvolvimento anormal das glândulas mamárias, reduzindo a quantidade de leite produzida durante a lactação, acarretando em perdas econômicas. Tanto a detecção da claudicação quanto a classificação da condição corporal são feitos por meios subjetivos e dependentes da opinião pessoal do tratador, o que pode gerar divergências entre as classificações dadas por cada indivíduo. Destaca-se, portanto, a importância do reconhecimento precoce de animais que apresentam condições físicas fora dos padrões exigidos, visando a prevenção de perdas produtivas causadas tanto pelo agravamento das condições apresentadas quanto pelo grande impacto no bem-estar dos animais. Tendo-se isso em vista, o presente trabalho visou obter três características (escore de condição corporal, massa corporal e espessura de toucinho) por meio de imagens em profundidade, que se mostraram eficazes na obtenção dessas características em outros animais (suínos machos não- castrados e vacas leiteiras). Além disso, buscou-se desenvolver um método para a detecção precoce de claudicação em matrizes suínas, utilizando-se a abordagem da cinemática dos animais, que vem dando bons resultados e cujas dificuldades têm potencial para serem sanadas por meio do uso de imagens em profundidade em vez do método de marcadores reflexivos utilizado atualmente. Para predizer a condição corporal, uma regressão linear múltipla foi obtida usando o menor eixo da elipse ajustada ao redor do corpo da matriz suína, a largura dos ombros e o ângulo da curvatura da última costela. Para predizer a espessura de toucinho, foi realizada uma regressão linear múltipla usando a altura curvatura da última da costela, o perímetro do corpo da matriz, o maior eixo da elipse ajustada, o comprimento do focinho à cauda e o escore predito da condição corporal. Foi possível obter a massa corporal com uma regressão linear simples usando o volume projetado do corpo das matrizes. Para detecção de claudicação, três modelos apresentaram a melhor precisão (76,9%): análise discriminante linear, 1 vizinho mais próximo e 10 vizinhos mais próximos. As variáveis de entrada utilizadas nos modelos foram obtidas a partir de vídeos em profundidade (número, tempo e comprimento de passos para cada uma das quatro regiões analisadas-ombros esquerdo e direito e quadris esquerdo e direito; tempo total de caminhada e número de máximos locais para a região da cabeça). Como resultado desses estudos, observou-se que câmeras em profundidade podem ser utilizadas na automação de medidas de peso, condição corporal, espessura de toucinho e claudicação de matrizes suínas.
437

A Rosa dos Ventos dos Sertões do Norte: dinâmicas do território e exploração colonial (c. 1660 - c. 1810) / The Rose of the Winds of the Northern Sertões: dynamics of the territory and colonial exploration c. 1660 - c. 1810

Rolim, Leonardo Candido 11 March 2019 (has links)
Esta tese analisa os processos de conquista e colonização dos Sertões do Norte, entre 1660 e 1810, para entender como as dinâmicas do território e a exploração colonial desses sertões formaram uma região fundamental para a consolidação de uma matriz territorial na América Portuguesa. Foi a partir conjuntura de expansão das conquistas atlânticas de Portugal, em meados do século XVII, que as dinâmicas dos territórios situados no interior do continente foram alvo de incursões em busca de riquezas minerais, indígenas para escravizar e terras para criar gado. Entendemos, neste trabalho, essa zona de expansão fronteiriça entre o sudeste da capitania do Maranhão e o noroeste das capitanias de Pernambuco e Bahia, como uma região que possuía características em comum, os Sertões do Norte. Ao longo do século XVIII os movimentos de conquista e o estabelecimento da colonização nessa área gerou conflitos e disputas jurisdicionais entre agentes administrativos dos corpos civil e eclesiásticos, além de ter sido objeto de projetos e políticas de colonização por parte de funcionários ilustrados. / This thesis analyses the processes of conquest and colonization of the Sertões do Norte between 1660 and 1810 to understand how the dynamics of the territory and the colonial exploration of these sertões formed a fundamental region for the consolidation of a territorial matrix in Portuguese America. It was from the mid-17th century expansion of the Atlantic conquests of Portugal that the dynamics of the interior territories of the continent were incursions in search of mineral wealth, indigenous to enslave and land to raise cattle. This area of frontier expansion between the southeaster captaincy of Maranhão and the north western captaincies of Pernambuco and Bahia, as a region with characteristics in common, the Sertões do Norte. Throughout century XVIII the movements of conquest and the establishment of colonization in this area generated conflicts and jurisdictional disputes between administrative agents of the civil and ecclesiastical bodies, besides being object of projects and policies of colonization by enlightened officials.
438

Industrihampa -hinder och drivkrafter för en utökad och kommersiell odling i Sverige

Böcker, Helena, Lind, Paulina January 2019 (has links)
Klimatförändringarna är en av vår tids största miljöproblem. Kött är det livsmedel som ger störst klimatpåverkan då ca 70 procent av de grödor som odlas används som djurfoder och idisslande djur släpper ut metan. Nästan en femtedel av de globala utsläppen av växthusgaser kommer från animalieproduktion. Betesdjur är dock avgörande för att nå de nationella miljömålen ”Ett rikt odlingslandskap” och ”Ett rikt växt- och djurliv”. Industrihampa är en gröda som kan användas som proteinfodertillskott och för att minska metangasbildningen under matspjälkningsprocessen hos idisslare. Hampan har också stora möjligheter att bidra positivt till att nå ett flertal av de andra nationella miljömålen då den kan ersätta fossila råvaror inom energi, bygg- och tillverkningsindustrin samt minska behovet av mineralgödsel i jordbruket. Syftet med detta examensarbete är att undersöka vilka hinder och drivkrafter som finns för en utökad och kommersiell hampaproduktion i Sverige. Genom att även undersöka om odling och användning av industrihampa ur ett kretsloppsperspektiv kan vara en del av lösningen i att bromsa klimatförändringarna, avser arbetet att förmedla kunskap om hur industrihampa kan minska klimatpåverkan från köttdjursuppfödning i Sverige och bidra till uppfyllandet av flera nationella miljömål. En litteraturstudie har gjorts för att få en djupare kunskap om problematiken kring klimatförändringar kopplat till lantbruk och köttdjursuppfödning samt för att bättre förstå hur industrihampa skulle kunna motverka detta. Intervjuer har utförts med hampaodlare, andra lantbrukare, intresseorganisationer och myndigheter för att samla in data om orsakerna till att odlingen av hampa i Sverige är så begränsad. Resultaten visar att hinder för en utökad och kommersiell odling är låg kunskap om hampan och dess egenskaper, dyrt utsäde, brist på lämpliga maskiner och en lagstiftning som ger utrymme för bred tolkning som narkotika och läkemedelskopplade tolkningar. Drivkrafter för ökad hampaodling är bland annat att grödan är mycket intressant och har stor potential att användas som råvara inom ett brett användningsområde. Den har god konkurrens mot ogräs och den är bra för miljön då den kan sanera mark som är förorenad av tungmetaller samt kan ersätta fossila material i tillverkningsindustrin och bomull i textilindustrin. Studien drar genom litteraturstudien slutsatsen att odling och användning av hampa i teorin har goda förutsättningar att bidra till att nå elva av sexton nationella miljömål. Drivkrafter för en ökad odling är en nyfikenhet på grödan, hampans potential att ut ett miljöperspektiv ersätta sämre råvaror och material samt konkurrensförmågan mot ogräs och minskat behov av växtskyddsmedel. Dock framkommer det ett flertal aspekter i intervjustudien som visar att i praktiken finns hinder som påverkar och hämmar en utökad och kommersiell odling av hampa, och därmed även möjligheten att bidra till att nå miljömålen. Lagstiftningen behöver förtydligas både för odlare samt myndigheter för att undvika osäkerhet och tolkningsproblem kring industrihampa kontra droghampa. Kunskapen om odling och användning av hampan behöver öka samt spridas. Större efterfrågan på hampa som råvara behövs. Här ligger ett stort ansvar på Sveriges regering och tillverkningsindustrin att lyfta fram grödan som ett alternativ.
439

The molecular basis for the resistance of Fasciola hepatica to cellular cytotoxicity

Prowse, Rhoda, 1975- January 2003 (has links)
Abstract not available
440

Mapping land-use in north-western Nigeria (Case study of Dutse)

Anavberokhai, Isah January 2007 (has links)
<p>This project analyzes satellite images from 1976, 1985 and 2000 of Dutse, Jigawa state, in north-western Nigeria. The analyzed satellite images were used to determine land-use and vegetation changes that have occurred in the land-use from 1976 to 2000 will help recommend possible planning measures in order to protect the vegetation from further deterioration.</p><p>Studying land-use change in north-western Nigeria is essential for analyzing various ecological and developmental consequences over time. The north-western region of Nigeria is of great environmental and economic importance having land cover rich in agricultural production and livestock grazing. The increase of population over time has affected the land-use and hence agricultural and livestock production.</p><p>On completion of this project, the possible land use changes that have taken place in Dutse will be analyzed for future recommendation. The use of supervised classification and change detection of satellite images have produced an economic way to quantify different types of landuse and changes that has occurred over time.</p><p>The percentage difference in land-use between 1976 and 2000 was 37%, which is considered to be high land-use change within the period of study. The result in this project is being used to propose planning strategies that could help in planning sustainable land-use and diversity in Dutse.</p>

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