Inestabilidad de la leche asociada a componentes lácteos y estacionalidad en vacas a pastoreo

The aim of this work was to characterize dairy herds which presented positive result for alcohol test in milk showing no acidity; and to compare them to a dairy herd with negative result for same test, considering the seasonal effect. Four dairy milk herds were studied (three positives to alcohol test and one with negative result). Milk samples were collected during 3 months in winter season (season 1) and 3 months in summer lactation (season 2) for 2 years. A subsample of the diets were prepared and submitted to proximal analysis for ME content, Ca, P, Mg and K. Milk subsamples were analyzed for protein, lactose, Ca, Mg, P, pH, alcohol test, titratable acidity and proteasic activity. In cases negative to alcohol test, a high correlation index with milk crude protein, diet crude protein, milk phosphorus and lactose were observed. Dairy herds positive to alcohol test were highly correlated with lower dry matter content and a high content of crude fiber, besides these herds presented lower milk protein concentration. It was possible to notice an effect of feeding management in the instability of the milk. Summer's lactations under feeding stress condition would present milk instability.The aim of this work was to characterize dairy herds which presented positive result for alcohol test in milk showing no acidity; and to compare them to a dairy herd with negative result for same test, considering the seasonal effect. Four dairy milk herds were studied (three positives to alcohol test and one with negative result). Milk samples were collected during 3 months in winter season (season 1) and 3 months in summer lactation (season 2) for 2 years. A subsample of the diets were prepared and submitted to proximal analysis for ME content, Ca, P, Mg and K. Milk subsamples were analyzed for protein, lactose, Ca, Mg, P, pH, alcohol test, titratable acidity and proteasic activity. In cases negative to alcohol test, a high correlation index with milk crude protein, diet crude protein, milk phosphorus and lactose were observed. Dairy herds positive to alcohol test were highly correlated with lower dry matter content and a high content of crude fiber, besides these herds presented lower milk protein concentration. It was possible to notice an effect of feeding management in the instability of the milk. Summer's lactations under feeding stress condition would present milk instability.El objetivo de este trabajo fue caracterizar rebaños lecheros que presentaban muestras de leche positivas a la prueba de alcohol sin estar ácidas, y compararlos con predios negativos a esta prueba, considerándose el efecto de la estacionalidad. Se estudiaron cuatro rebaños (tres positivos a la prueba de alcohol y uno negativo). En dos años, se muestreó leche durante tres meses en lactancias de invierno (época 1) y tres meses en lactancias de verano (época 2). En la dieta, se realizó análisis proximal relativo a EM, Ca, P, Mg y K. En leche, se determinó proteína, lactosa, Ca, P, Mg, K, pH, prueba de alcohol, acidez titulable y actividad proteásica. En casos negativos a la prueba de alcohol, se observó alta correlación entre proteína cruda láctea, proteína cruda en alimento, fósforo lácteo y lactosa. Los predios positivos a la prueba de alcohol se correlacionaron fuertemente con la menor concentración de materia seca y el alto contenido de fibra cruda, además presentaron menor concentración de proteína láctea. Ello indicaría que existió un efecto del manejo alimentario sobre la inestabilidad de la leche. Las lactancias desarrolladas durante la sequía estival sufren de un stress alimenticio, por lo cual podrían presentar inestabilidad láctea

Resiliência acadêmica: Compreender as relações familiares que a promovem

The study of academic resilience is relevant to the educational environment because of its positive role in the educational and socio-emotional development of children and adolescents. The objective of the article was to understand the family relationships that favor academic resilience in elementary school students, first to fourth year, from vulnerable contexts. The methodology used to respond to the objectives considered a grounded theory design, since it sought to describe and understand the meanings constructed intersubjectively by the participants. The participants were selected through a guided theoretical sampling, in which data collection and analysis were carried out in parallel, with the main theoretical guide being the emerging theoretical model. The data collection strategy considered the application of 27 semi-structured interviews to vulnerable families, for which a thematic guide was prepared containing the main topics to be addressed with the participants, and without a standard scheme of response categories. Data analysis protocols and procedures were based on coding paradigm and included open, axial and selective coding levels. The results suggest that family relationships based on communication, trust, and strict academic standards combined with parental emotional support, favor academic resilience. Likewise, high academic expectations and school commitment, characterized by a component of parents affection towards school, contribute to promoting academic resilience. Finally, results are discussed from national and international theoretical evidence available, highlighting those healthy family relationships that promote academic resilience.El estudio de la resiliencia académica resulta relevante, por el rol positivo que ejerce sobre el desarrollo educativo y socioemocional de niños, niñas y adolescentes. El objetivo del artículo fue comprender las relaciones familiares que favorecen la resiliencia académica en estudiantes de enseñanza básica, primero a cuarto año, provenientes de contextos vulnerables. La metodología utilizada para dar respuesta a los objetivos, consideró un diseño de teoría fundamentada, ya que se buscó describir y comprender los significados construidos intersubjetivamente por las personas participantes. La selección de quienes participaron se realizó mediante un muestreo teoréticamente guiado, en donde recolección y análisis de datos se realizaron de manera paralela, y la guía principal fue el modelo teórico emergente. La estrategia de recogida de datos consideró la aplicación de 27 entrevistas semiestructuradas a familias vulnerables; para ello se elaboró una guía temática, que contenía los principales tópicos a abordar con las personas participantes, sin un esquema estándar de categorías de respuesta. Los protocolos y procedimientos de análisis de datos se basaron en el paradigma de codificación e incluyó los niveles de codificación abierta, axial y selectiva. Los resultados sugieren que las relaciones familiares basadas en la comunicación, confianza, normas académicas estrictas combinadas con apoyo emocional parental favorecen la resiliencia académica. De la misma forma, altas expectativas académicas y compromiso escolar, caracterizado por un componente de afectividad de los padres y madres hacia el colegio, contribuyen a promover la resiliencia académica. Finalmente, se discuten los resultados a partir de la evidencia teórica nacional e internacional disponible, destacando aquellas relaciones familiares saludables que estimulan la resiliencia académica.O estudo da resiliência acadêmica é relevante para o meio educacional pelo papel positivo que desempenha no desenvolvimento educacional e socioemocional nas crianças e nos adolescentes. O objetivo do artigo foi compreender as relações familiares que favorecem a resiliência acadêmica em alunos do ensino fundamental, do primeiro ao quarto ano, de contextos vulneráveis. A metodologia utilizada para responder aos objetivos foi baseada em um desenho teórico, uma vez que buscou descrever e comprrender os significados construídos intersubjetivamente pelos participantes. A seleção dos participantes foi realizada através de uma amostra guiada teoricamente, onde a recolha e análise dos dados foram realizada em paralelo, sendo o principal guia o modelo teórico emergente. A estratégia de coleta de dados considerou a aplicação de 27 entrevistas semiestruturadas às famílias vulneráveis, para as quais foi elaborado um guia temático, que continha os principais temas a serem discutidos com os participantes, sem um esquema padrão de categorias de resposta. Os protocoloos e procedimentos de análise de dados foram baseados no paradigma de codificação e incluíram níveis de codificação abertos, axiais e seletivos. Os resultados sugerem que as relações familiares baseadas na comunicação, confiança, padrões académicos rigorosos combinados com o apoio emocional dos pais fomentam a resiliência académica. Da mesma forma, as elevadas expectativas académicas e o compromisso da escola, caracterizado por uma componente de afeto parental pela escola, contribuem para promover a resiliência académica. Finalmente, os resultados são discutidos com base nas evidências teóricas nacionais e internacionais disponíveis, destacando-se as relações familiares saudáveis que estimulam a resiliência académica