4 research outputs found

    Contraste leiteiro: ferramenta de monitorização para uma maior eficiência das explorações de bovinos leiteiros

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    Os resultados do contraste leiteiro são uma ferramenta de gestão. Desequilíbrios nutricionais, metabólicos e infecciosos podem ser diagnosticados pela concentração de β-hidroxibutirato(BHB), azoto ureico(MUN), gordura, proteína, relação gordura/proteína e células somáticas(SCC) do leite. O objetivo é avaliar a variação destes parâmetros segundo fatores não-nutricionais e a inter-relação entre estes. Analisou-se 110461 amostras de 9523 vacas recolhidas mensalmente entre janeiro de 2015 e março de 2017 em 27 efetivos do sul de Portugal. Ajustou-se dois modelos lineares generalizados mistos para determinar os fatores associados à concentração de BHB e MUN serem superiores a 0,2mmol/L e 300mg/kg, respetivamente. Verificou-se um considerável efeito dos fatores não-nutricionais, embora variável consoante o fator e o parâmetro. Os modelos demonstraram que a produção de leite, fase e número de lactação e a relação gordura/proteína influenciam a concentração de BHB e MUN. A concentração de BHB também é influenciada pela SCC e gordura, a MUN pela proteína; MILK RECORDING: MONITORING TOOL FOR GREATER DAIRY FARMS EFFICIENCY ABSTRACT: Milk recording results are a management tool. Nutritional, metabolic and infectious disorders can be diagnosed by β-hydroxybutyrate(BHB), milk urea nitrogen(MUN), fat, protein, relation fat/protein and somatic cells concentration in milk. The objective is analyzed the variation of these parameters according to non-nutritional factors and the interrelation between them. This study analyzed 110,461 samples of 9,523 cows collected monthly from January 2015 to March 2017 from 27 herds of South of Portugal. Two generalized linear mixed regression models were constructed to determine non-nutritional factors associated with concentration of BHB and MUN greater than 0,2mmol/L and 300mg/kg, respectively. There was a considerable effect of non-nutritional factors, although variable according to factor and parameter. Models show that milk production, stage and number of lactation, and relation fat/protein influenced BHB and MUN concentration. BHB concentration is also influenced by somatic cells and milk fat, MUN concentration by milk protein

    Currículo e Ensino de História: um estado do conhecimento no Brasil

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    Characterisation of microbial attack on archaeological bone

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    As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved
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