This thesis is concerned with the application of recently developed epidemiological and statistical tools to inform the optimisation of a national surveillance strategy of considerable importance to human health. The results of a series of epidemiological investigations of surveillance strategies for zoonotic Salmonella are presented. Salmonella are one of the most common and serious zoonotic foodborne pathogenic bacteria globally. These studies were motivated by the increasing focus on the cost-effectiveness of surveillance while maintaining consumer confidence in food supply. Although data from the Danish Salmonella surveillance and control programme has been used in these investigations, the techniques may be readily applied to other surveillance data of similar quality. The first study describes the spatial epidemiological features of Danish Salmonella surveillance and control programme data from 1995 to 2004, using a novel method of spatially adaptive smoothing. The conditional probability of a farm being a case was consistently high in the the south-west of Sonderjylland on the Jutland peninsula, identifying this area for further investigation and targeted surveillance. The identification of clustering of case farms led into the next study, which closely examines one year of data, 2003, for patterns of spatial dependency. K-function analyses provided evidence for aggregation of Salmonella case farms over that of all farms at distances of up to six kilometres. Visual semivariogram analyses of random farm-level effects from a Bayesian logistic regression model (adjusted for herd size) of Salmonella seropositivity, revealed spatial dependency between pairs of farms up to a distance of four kilometres apart. The strength of the spatial dependency was positively associated with slaughter pig farm density. We describe how this might inform the surveillance programme by potentially targeting herds within a four kilometre radius of those with high levels of Salmonella infection. In the third study, farm location details, routinely recorded surveillance information, and industry survey data from 1995 were combined to build a logistic seroprevalence model. This identified wet-feeding and specific pathogen free herd health status as protective factors for Salmonella seropositivity, while purchasing feed was a risk factor. Once adjusting for these covariates, we identified pockets of unexplained risk for Salmonella seropositivity and found spatial dependency at distances of up to six km (95% CI: 2–35 km) between farms. A generalised linear spatial model was fitted to the Jutland data allowing formal estimation of the range of spatial correlation and a measure of the uncertainty about it. There was a large within-farm component to the variance, suggesting that gathering more farm level information would be advantageous if this approach was to be used to target surveillance strategy. The fourth study again considers data from the whole study period, 1995 to 2004. A detailed temporal analysis of the data revealed there was no consistent seasonal pattern and correspondingly no benefit in targeting sampling to particular times of the year. Spatiotemporal analyses suggested a local epidemic of increased seroprevalence occured in west Jutland in late 2000. Lorelogram analyses showed a defined period of statistically significant temporal dependency, suggesting that there is little value in sampling more frequently than every 10 weeks on the average farm. The final study uses findings from the preceding chapters to develop a zero-inflated binomial model which predicts which farms are most at risk of Salmonella, and then preferentially samples these high-risk farms. This type of modelling allows assessment of similarities and differences between factors that affect herd infection status (introduction) and those that affect the seroprevalence in infected herds (persistence and spread). The model suggested that many of the herds where Salmonella was not detected were infected but at a low prevalence. Using cost and sensitivity, we compared the results with those under the standard sampling scheme based on herd size, and the recently introduced risk-based approach. Model based results were less sensitive, but showed significant cost savings. Further model refinements, sampling schemes, and the methods to evaluate their performance are important areas for future work, and should continue to occur in direct consultation with Danish authorities.

This thesis is concerned with the application of recently developed epidemiological and statistical tools to inform the optimisation of a national surveillance strategy of considerable importance to human health. The results of a series of epidemiological investigations of surveillance strategies for zoonotic Salmonella are presented. Salmonella are one of the most common and serious zoonotic foodborne pathogenic bacteria globally. These studies were motivated by the increasing focus on the cost-effectiveness of surveillance while maintaining consumer confidence in food supply. Although data from the Danish Salmonella surveillance and control programme has been used in these investigations, the techniques may be readily applied to other surveillance data of similar quality. The first study describes the spatial epidemiological features of Danish Salmonella surveillance and control programme data from 1995 to 2004, using a novel method of spatially adaptive smoothing. The conditional probability of a farm being a case was consistently high in the the south-west of Sonderjylland on the Jutland peninsula, identifying this area for further investigation and targeted surveillance. The identification of clustering of case farms led into the next study, which closely examines one year of data, 2003, for patterns of spatial dependency. K-function analyses provided evidence for aggregation of Salmonella case farms over that of all farms at distances of up to six kilometres. Visual semivariogram analyses of random farm-level effects from a Bayesian logistic regression model (adjusted for herd size) of Salmonella seropositivity, revealed spatial dependency between pairs of farms up to a distance of four kilometres apart. The strength of the spatial dependency was positively associated with slaughter pig farm density. We describe how this might inform the surveillance programme by potentially targeting herds within a four kilometre radius of those with high levels of Salmonella infection. In the third study, farm location details, routinely recorded surveillance information, and industry survey data from 1995 were combined to build a logistic seroprevalence model. This identified wet-feeding and specific pathogen free herd health status as protective factors for Salmonella seropositivity, while purchasing feed was a risk factor. Once adjusting for these covariates, we identified pockets of unexplained risk for Salmonella seropositivity and found spatial dependency at distances of up to six km (95% CI: 2–35 km) between farms. A generalised linear spatial model was fitted to the Jutland data allowing formal estimation of the range of spatial correlation and a measure of the uncertainty about it. There was a large within-farm component to the variance, suggesting that gathering more farm level information would be advantageous if this approach was to be used to target surveillance strategy. The fourth study again considers data from the whole study period, 1995 to 2004. A detailed temporal analysis of the data revealed there was no consistent seasonal pattern and correspondingly no benefit in targeting sampling to particular times of the year. Spatiotemporal analyses suggested a local epidemic of increased seroprevalence occured in west Jutland in late 2000. Lorelogram analyses showed a defined period of statistically significant temporal dependency, suggesting that there is little value in sampling more frequently than every 10 weeks on the average farm. The final study uses findings from the preceding chapters to develop a zero-inflated binomial model which predicts which farms are most at risk of Salmonella, and then preferentially samples these high-risk farms. This type of modelling allows assessment of similarities and differences between factors that affect herd infection status (introduction) and those that affect the seroprevalence in infected herds (persistence and spread). The model suggested that many of the herds where Salmonella was not detected were infected but at a low prevalence. Using cost and sensitivity, we compared the results with those under the standard sampling scheme based on herd size, and the recently introduced risk-based approach. Model based results were less sensitive, but showed significant cost savings. Further model refinements, sampling schemes, and the methods to evaluate their performance are important areas for future work, and should continue to occur in direct consultation with Danish authorities.

La période d'abattage est complexe car elle se compose d'une succession de situations associées à une multitude de facteurs de stress. L'animal est généralement privé d'alimentation et est ensuite confronté à un environnement changeant et contraignant qui demande en permanence des adaptations comportementales et physiologiques effectant son état émotionnel. Les objectifs de cette thèse sont (i) de mieux comprendre l'origine des réactions des bovins au cours de la période d'abattage, et (ii) d'évaluer leur stress d'un point de vue comportemental et physiologique à l'aide d'études menées à la fois en abattoir industriel et dans des conditions expérimentales. Nos travaux sur le terrain mettent en évidence la nécessité de tenir compte de toutes les procédures d'abattage, y compris les plus courtes, ainsi que des contraintes organisationnelles des abattoirs car elles influencent l'état de stress des bovins. Pendant la période d'élevage, la caractérisation des bovins selon leur réactivité émotionnelle, qui dépend en partie de leur expérience antérieure et de leur race, permet d'identifier les animaux susceptibles de réagir plus fortement aux procédures d'abattage. Elle permet également de déterminer les facteurs de stress prépondérants associés à ces procédures

<p>Livestock keeping has been the essential source of livelihood in Babati District for many hundreds of years. The traditional ecological knowledge about this semi-arid environment has influenced the general view on livestock management. This essay discusses the measures that are, or could be taken in Babati District to prevent overstocking and overgrazing in the woodlands. With the continuing population density increase also the livestock population grows. More houses and roads are built and the grazing lands diminish. To avoid overgrazing forest management programmes restrict grazing in forests. This additionally decreases availability of grazing land. My conclusion is that minimizing number of livestock is necessary to not exceed carrying capacity of pasture during drought. Hence this is not free from problems since it is traditionally rooted to have a large number of livestock as a buffer of energy and wealth. One solution for both how to prevent overstocking and how to survive with small number of livestock is to practise zero-grazing. Zero-grazing is to keep a small number of healthy big cattle e.g. exotic cows or crossbreeds in stables or tied up. However, when tying cattle on the spot the fact that cattle have four legs is disregarded.</p>

As exigências das condições higiênico-sanitárias na produção de animais de interesse zootécnico vêm aumentando progressivamente dada à necessidade de aliar-se produtividade a produtos de alta qualidade para atender a mercados consumidores cada vez mais exigentes. Nesse sentido, a utilização de antimicrobianos, tanto na profilaxia como na terapêutica, permanece como estratégia de controle para vários microrganismos patogênicos, de importância não apenas para a produção animal como também para a saúde humana, ainda que restrições ao uso indiscriminado desses produtos têm se intensificado. Não obstante, o uso excessivo desses produtos está associado à seleção de microrganismos resistentes nas áreas de produção. Por outro lado, investigações sobre circulação de cepas resistentes em rebanhos animais, até então restritas a populações humanas, ainda permanecem limitadas no Brasil. Bactérias do gênero Enterococcus, integrantes usuais da microbiota gastrointestinal animal e humana, são indicadoras ambientais de contaminação fecal e tem-se tornado objeto de preocupação em saúde pública e veterinária dada a ocorrência de cepas resistentes à vancomicina (VRE). O presente trabalho teve como objetivo isolar, quantificar e caracterizar VRE presentes em amostras fecais de ovinos oriundos de pequenas propriedades das regiões centro-leste e nordeste do estado de São Paulo. Para tanto, 132 amostras fecais foram coletadas diretamente do reto dos animais ou do piso das instalações. As amostras foram semeadas em ágar m-Enterococcus e subcultivadas em Ágar Bile Esculina acrescido de 6 &micro;g/mL de vancomicina (ABEV), para confirmação de Enterococcus spp e detecção de cepas resistentes. Procedeu-se igualmente a observação da morfologia, características tintoriais, bioquímicas e moleculares. O número máximo de Enterococcus spp. encontrado foi de 2,6 × 105 e 1,70 × 105 UFC/g de fezes do ambiente e dos animais, respectivamente. Na caracterização bioquímica espécies mais prevalentes foram: Enterococcus faecalis e Vagococcus fluvialis. No ABEV, houve crescimento de colônias VRE em 33 das 84 amostras de ovinos-caprinos e em 21 das 48 amostras ambientais, representando, respectivamente 46,7% e 29,3% das amostras analisadas. A análise por multiplex PCR das 54 cepas VRE obtidas indicaram que 23 (43%), 22 (41%), 2 (3,5%) e 2 (3,5%) foram positivas, respectivamente, para os genes vanC2/C3, vanC1, vanA e vanB, sendo que para 5,3% dos isolados nenhum produto foi amplificado, sugerindo a possível ocorrência de genes dos demais grupos van conhecidos entre os isolados. Os resultados obtidos indicam, de forma inédita no país, a circulação de VRE em propriedades produtoras de ovinos e caprinos, sem ocorrência de manifestações clínicas aparentes nos animais, porém com possíveis riscos à saúde dos produtores e profissionais envolvidos, bem como a eventuais consumidores. / Demands for sanitary conditions in animal farming have been increasing progressively given the need to combine productivity and high quality products to support increasingly demanding consumer markets. In this context, antimicrobial drugs used in prevention as well as in therapy remain as the control strategy for several pathogenic microorganisms, not important only in animal production but also in human health, although restrictions for the indiscriminate use of these drugs have been intensified. However, the excessive use of these products has been associated to the selection of resistant microorganisms in production areas. On the other hand, investigation on strains of public health importance circulating in animal herds is still limited in Brazil. Enterococcus genus bacteria, usually present in animal and human gastrointestinal microbiota, are environmental indicators of fecal contamination and have become a concerning subject in public and veterinary health given the occurrence of strains resistant to vancomycin (VRE). The present study aimed to isolate, quantify and characterize VRE present in stool samples of sheep and goats from several farms in the center-east and northeast regions of São Paulo State. Swabs collected one hundred and thirty-two stool samples either directly from the animal\'s rectum or from the ground. Samples were plated onto m-Enterococcus agar plates and subcultivated in Bile esculin agar with 6 &micro;g/mL of vancomycin (BEAV) to confirm Enterococcus spp and detect resistant samples. Colonies were identified by colonial morphology, Gram\'s staining, biochemical, and molecular profile. The highest colony count was equal to 2.6 × 105 and 1.7 × 105 CFU/g of feces from environmental and animal samples, respectively. Regarding biochemical characterization, Enterococcus faecalis e Vagococcus fluvialis were the most prevalent species. VRE was detected on BEAV in 33 out of 84 sheep-goat samples and in 21 out of 48 ambient samples, indicating a positivity rate of 46.7% and 29.3% respectively in the investigated samples. Analysis by multiplex PCR of the obtained 54 VRE strains indicated that 23 (43%), 22 (41%) 2 (3.5%) and 2 (3.5%) were positive, respectively, for the vanC2/C3, vanC1, vanA and vanB genes, and no product was amplified for 5.3% of the isolates, suggesting the possible occurrence of other known van gene groups among the isolates. The results obtained in this study indicate, for the first time in the studied areas, the circulation of VRE in sheep and goat farms, with no occurrence of apparent clinical signs in the animals, but with possible health risks to the farmers and workers involved, as well as potential consumers.

A heterogeneidade espacial induzida pelo pastejo tem sido reconhecida como um componente crucial para o manejo sustentável dos ecossistemas. Ainda assim, a maioria das intervenções realizadas pelo homem tende à homogeneização dos ambientes, inclusive no manejo dos animais. Neste estudo, foi investigado o efeito da intensidade de pastejo sobre a heterogeneidade espacial da vegetação e a criação de uma estrutura ótima para a maximização da taxa de ingestão dos animais, e suas implicações em um Sistema Integrado de Produção Agropecuária (SIPA). O experimento foi conduzido durante o inverno de 2015, no estado do Rio Grande do Sul, Brasil, em um protocolo experimental de longo prazo iniciado em 2001. Os tratamentos foram arranjados em um delineamento de blocos completamente casualizados com três repetições e consistiram em diferentes intensidades de pastejo por bovinos em pasto misto de azevém anual (Lolium multiflorum Lam.) e aveita-preta (Avena strigosa Schreb.): pastejo intenso (P10), pastejo moderado (P20), pastejo moderado-leve (P30), pastejo leve (P40) e ausência de pastejo (SP). A heterogeneidade espacial da vegetação aumentou com a diminuição da intensidade de pastejo. Maior heterogeneidade e estruturação espacial foram identificadas no mês de julho, durante o período vegetativo de ambas as espécies forrageiras. O início do florescimento ocasionou uma diminuição na dependência espacial e um incremento na heterogeneidade abaixo da escala de observação. P10 apresentou dossel homogêneo espacialmente ao longo de todo o ciclo de pastejo, composto em sua maior parte por uma vegetação excessivamente pastejada (<10 cm). P20 apresentou maior participação de alturas ótimas para a maximização da taxa de ingestão (15 a 29,99 cm) ao longo do ciclo de pastejo. Com o aumento da intensidade de pastejo, aumentaram também a carga animal (CA, P<0,05) e o ganho de peso vivo por área (GPV, P<0,05). A intensidade de pastejo moderada (P20) apresentou maior ganho médio diário (GMD, P<0,05) quando comparada ao pastejo intenso (P10), não diferindo, no entanto, de P30 e P40. Sendo assim, a utilização de intensidades de pastejo moderadas constitui na melhor alternativa para conciliar produtividade e conservação ambiental em SIPA. / Spatial heterogeneity induced by grazing has been recognized as a crucial component to the ecosystems sustainable management. Even so, most of the interventions made by humans tend to homogenize the environments, including animal management. In this study, we investigated the effect of grazing intensity on vegetation spatial heterogeneity and creation of an optimal structure for maximizing animals intake rate, and the implications for an Integrated Crop-Livestock System (ICLS). The experiment was carried out during winter 2015, in the Rio Grande do Sul state, Southern Brazil, in a long-term experimental protocol implemented in 2001. Treatments were arranged in a randomized complete block design with three replicates and consisted of different grazing intensities by steers on Italian ryegrass (Lolium multiflorum Lam.) and black oat (Avena strigosa Schreb.) mixed pastures: intensive grazing (P10), moderate grazing (P20), moderate-light grazing (P30), light grazing (P40) and absence of grazing (NG). Vegetation spatial heterogeneity increased with decreasing grazing intensities. Greater heterogeneity and spatial dependence were identified in July, during both forage species growing season. The flowering initiation caused a decrease in spatial dependence and an increase in small scale spatial heterogeneity (nugget effect). P10 showed a spatially homogeneous canopy throughout the grazing cycle, composed mostly by an excessively grazed vegetation (<10 cm). P20 showed higher participation of optimal heights for maximizing the intake rate (15 to 29,99 cm) throughout the grazing cycle. Increasing grazing intensity also increased stocking rate (SR, P<0,05) and liveweight gain per area (LWG, P<0,05). Moderate grazing intensity (P20) showed higher average daily gain (ADG, P<0,05) compared to intensive grazing (P10), without difference, however, from P30 and P40. Therefore, the utilization of moderate grazing intensities is the best alternative to reconcile productivity and environmental conservation in ICLS.

As redes de sensores sem fio, aplicadas à automação do controle de ambientes representam um paradigma emergente da computação, onde múltiplos nós providos de sensores, sistemas computacionais autônomos e capacidade de comunicação sem fio, conformam uma rede cuja topologia altamente dinâmica permite adquirir informações sobre sistemas complexos sendo monitorados. Um dos fatores essenciais para obter um ganho na produtividade avícola é o controle da ambiência animal. Atualmente os métodos utilizados para o monitoramento e controle ambiental não podem considerar a grande quantidade de microambientes internos nos ambientes de produção animal e também requerem infraestruturas cabeadas complexas. Dentro desse contexto o objetivo deste trabalho foi desenvolver e testar um sistema automatizado de controle ambiental, através da utilização de sensores sem fio, que auxilie e proporcione maior segurança no controle de ambientes automatizados. O sistema monitora variáveis que influenciam na produtividade de aves, tais como temperatura e umidade e outras variáveis físico-químicas do aviário. A infraestrutura desenvolvida foi testada em um aviário experimental e resultou em um sistema seguro e com grande escalabilidade, que é capaz de controlar e monitorar o ambiente e ainda coletar e gravar dados. Foi utilizado o protocolo ZigBee&reg; para gerenciar o fluxo de dados do sistema. Foram feitas análises da eficiência de comunicação do sistema no aviário, monitorando os pacotes de dados perdidos. Os testes demonstraram uma perda de dados de aproximadamente 2% dos pacotes enviados, demonstrando a eficiência das redes ZigBee&reg; para gerenciar o fluxo de dados no interior do aviário. Desta forma, pode-se concluir que é possível e viável a implantação de uma rede ZigBee&reg;, para automatizar ambientes de produção animal com coleta de dados em tempo real, utilizando um sistema integrado via internet, que compreende: instrumentação eletrônica, comunicação sem fio e engenharia de software\". / Wireless sensor networks, applied to automation environments control represent an emerging computing paradigm where multiple nodes equipped with sensors, autonomous computing systems and wireless communication capability, make up a network with a highly dynamic topology allows acquiring information systems complex being monitored. One of the key factors for a gain in the poultry productivity is the control of animal ambience. Currently the methods used for environmental monitoring and control may pass large amount of internal microenvironments in animal production environments and also require complex wired infrastructure. In this context the aim of this study was to develop and test an automated environmental control through the use of wireless sensors that assist and provide greater security in the control of automated environments. The system monitors variables that influence the productivity of birds, such as temperature, humidity and other physical and chemical variables of the aviary. The developed infrastructure was tested in an experimental avian and resulted in a secure and highly scalable system, which is able to control and monitor the environment and still collect and record data. The ZigBee&reg; protocol was used to manage the system data flow. Communication efficiency analyzes were made in the aviary, monitoring the lost data packets. Tests have shown a data loss of around 2% of the packets sent demonstrating the efficiency of ZigBee&reg; networks to manage the data flow within an avian. Thus, one can conclude that it is possible and feasible the implementation of a ZigBee&reg; network to automate animal production environment with real-time data collection using an integrated internet system, comprising: electronic instrumentation, wireless communication and Software Engineering\".

Resumo: No Brasil, os biotérios de produção precisam atender elevada demanda de animais, com padrões genéticos e sanitários definidos e, por outro lado, existe a necessidade de considerar a crescente preocupação de setores da sociedade e dos órgãos reguladores, que trazem à discussão o tema do bem-estar dos animais de laboratório, em condição de cativeiro, mesmo que não estejam submetidos à experimentação. O objetivo deste estudo foi avaliar três idades de acasalamento (28, 45 e 60 dias) para camundongos da linhagem BALB/c, alojados em gaiolas enriquecidas ou não e suas influencias no desempenho produtivo. O experimento teve a duração de 310 dias, do primeiro acasalamento até o desmame da última ninhada. Usou-se 60 casais de camundongos da linhagem BALB/c, de padrão sanitário controlado, criados e mantidos em ambiente padronizado. Eles foram distribuídos em um delineamento inteiramente casualizado com arranjo fatorial 3 x 2 (três idades de acasalamento e alojamento com ou sem enriquecimento ambiental). Como forma de enriquecimento da gaiola foram utilizados tubos de papelão (com aproximadamente 10 cm de comprimento e 4 cm de diâmetro), previamente embalados e autoclavados. Foram analisadas características relacionadas à fertilidade, idade ao primeiro parto, intervalo entre partos, número de nascidos e desmamados totais e médio por ninhada, mortalidade pré-desmame e peso da ninhada ao desmame. Não houve efeito da interação enriquecimento x idade de acasalamento sobre as características estudadas. Tanto o enriquecimento, quanto a idade de acasalamento, influenciaram a mortalidade pré-desmame. Nas gaiolas enriquecidas a mortalidade pré-desmame foi mais baixa (P=0,01) que nas não enriquecidas (0,80 e 1,87 respectivamente). O acasalamento aos 28 dias resultou em mortalidade mais baixa (P = 0,01) comparado ao acasalamento aos 60 dias, enquanto o acasalamento... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In Brazil, the centers for production of laboratory animals need to meet a high demand for rodents with defined genetic and health status and, on the other hand, there is the need to consider the growing concern of the society and of the regulatory agencies regarding captive laboratory animals welfare, even though they are not under research protocols in those centers. The objective of this study was to evaluate the effect of three breeding ages (28, 45 and 60 days) on mice from the BALB/c strain, housed in enriched or non-enriched cages and their influence on the productive performance. The experiment lasted 310 days, from the first mating to weaning of the last litter. Sixty mouse couples from the BALB/c strain, with controlled health status, raised and kept under standardized environment were used. They were assigned to a completely randomized design in a 3 x 2 factorial arrangement (three breeding ages and cage with or without enrichment). Card paper tubes, approximately 10 cm long and with a diameter of 4 cm, were previously packed and autoclaved and used as cage enrichments. Traits related to fertility, age at first parturition, parturition interval, number born and weaned (total and litter average), pre-weaning mortality rate and litter weight at weaning were analyzed along the entire reproduction period. The breeding age x cage enrichment interaction did not affect any of traits under study, but each of these effects separately affected pre-weaning mortality. In the enriched cages, pre-weaning mortality was lower (P=0.01) than in non-enriched cages (0.80 vs. 1.87 deaths, respectively). Breeding at 28 days resulted in lower mortality (P= 0.01) compared to breeding at 60 days, whereas at 45 days an intermediary value was found (0.60, 2.25 and 1.16 deaths, respectively). No other effects of the treatments were detected (P>0.05) on the traits under study... (Complete abstract click electronic access below) / Orientador: Ana Silvia Alves Meira Tavares Moura / Coorientador: Vânia Gomes de Moura Mattaraia / Banca: Edson Ramos de Siqueira / Banca: Sueli Blanes Damy / Mestre

<p>This objective of this study was to determine the impact of antimicrobial carcass washes on beef trim quality in the production of frankfurters. Twenty-four beef carcasses were randomly applied a different antimicrobial wash treatments (TRT) during the harvest procedure: 82° C water (CON), peroxyacetic acid (PAA), or lactic acid (LA). Beef carcasses were analyzed for microbial counts and carcass pH. Frankfurters were produced using carcass trim at two different batter temperature processes (PROC): 4°C (CP) or 21°C (HP). Frankfurters were analyzed for cook loss, emulsion stability (ES), color (Minolta L*, a*, b*) over 60-day storage, purge loss, texture, and sensory analysis. LA carcass had a lower pH (6.36; <i>P</i><0.001) 30 min post wash compared to other wash treatments. Frankfurters produced from CON trim had the highest ES water (<i>P</i><0.0001) and ES fat (<i>P</i><0.0001) separation where the LA and PAA treatments were not significantly different (<i>P</i>>0.05). The HP frankfurters had less ES water (<i>P</i><0.0001) and ES fat separation (<i>P</i><0.0001) when compared to CP. However, the CP had a higher cook yield (<i>P</i>=0.002). The HP frankfurters had higher internal and external L* values (<i>P</i><.0001; <i>P</i><.0001, respectively). The CP frankfurters had a higher a* (redness) internal color values (<i>P</i><.0001). However, the HP frankfurters had a higher external a* value (<i>P</i><.0001). The HP frankfurters displayed higher internal and external b* (yellowness) values (<i>P</i><.0001). Sensory results displayed the CP frankfurter to have an increase in hardness (<i>P</i>=0.004), a decrease in cohesiveness (<i>P</i>=0.03) and an increase in juiciness (<i>P</i><.0001). Texture analysis hardness (<i>P</i>=0.009) and chewiness (<i>P</i>=0.01) results showed the CON frankfurters were significantly harder than PAA (<i>P</i><0.05), while LA were not different from CON or PAA frankfurters (<i>P</i>>0.05). The CP frankfurters were found to have a decrease in springiness (<i>P</i>=<.001) and cohesiveness (<i>P</i>=0.03). There was a significant difference in microbial reduction of pre to post wash petri film counts for all treatments (Log₁₀CFU/mL) of aerobic plate count (<i>P</i>= <0.0001), E.<i>coli</i> coliform (<i>P</i>= 0.0002), yeast (<i>P</i>=0.04) and mold (<i>P</i>= <0.001). TRT was found to be significant for APC (<i>P</i>=0.06) and yeast (<i>P</i>=0.004). Overall, our research indicated antimicrobial wash treatments have little effect on frankfurter quality and displayed viable methods for reducing microbial growth on beef carcasses. </p> <br>

Les objectifs du projet de thèse étaient: 1) d'apporter des connaissances sur le potentiel boucher et les qualités de la viande du cabri Créole, 2) de déterminer les principales conditions d'élevage et d'abattage qui influencent le potentiel boucher et les qualités de la viande. Concernant ce deuxième point le système d'alimentation et l'âge/poids d'abattage des animaux ont été les 2 principaux facteurs de variation. Deux essais ont été conduits. Le premier a mobilisé 91 chevreaux selon un dispositif factoriel 2x3 qui a permis de tester l'effet d'herbe seule versus une ration mixte (50 %) de concentré à 3 âges d'abattage: 7, 11 et 15 mois. Le deuxième essai a mobilisé 40 chevreaux alimentés recevant une ration composée d'herbe avec 0, 140, 240 ou 340 g/j d'un concentré commercial. Le principal résultat du travail de la thèse est qu'il est possible d'améliorer la vitesse de croissance (jusqu'à 85 g/j), le poids (jusqu'à 12 kg) la conformation des carcasses (jusqu'à 4 sur une note de 5) et la qualité la viande du caprin Créole au moyen de l'alimentation. L'alimentation à base d'herbe seule et les rations mixtes permettent potentiellement d'obtenir des carcasses de qualité assez similaires avec des durées d'engraissement variables. A l'intérieur des régimes herbe, le pâturage et l'auge ne conduisait pas aux mêmes résultats. En matière de qualité de la viande, il a été mis en évidence que comme chez tous les caprins, la viande de caprin Créole demeurait relativement maigre même avec des régimes riches en énergie du fait d'une accumulation préférentielle du gras dans la cavité abdominale (4-7 % du poids vif vide). En ce qui concerne les autres caractéristiques des viandes, tels que les profils d'AG et les niveaux de pH, ils sont similaires à ceux de nombreuses races. L'apport de concentrés n'a pas augmenté les AG hypercholestéromiants au sein des AGS dans la viande et a réduit le rapport n-6/n-3 sous la valeur de 4 avec un apport de 240 g de concentré soit un peu moins de 50 % de la ration. Les retombées de ce travail de thèse sont potentiellement importantes. Des bases sont jetées pour la promotion d'itinéraires techniques et de choix génétiques adaptés au contexte guadeloupéen et aussi la création d'une niche économique autour d'une viande de cabri labélisée. L'étude des qualités sensorielles, de l'impact du parasitisme dans les systèmes pâturés et l'évaluation technico-économique de nouveaux systèmes d'alimentation basés sur l'emploi des matières premières locales constituent de nouvelles pistes de recherches mises en évidence par ce travail