Abstract Introduction: The History of Mathematics (HM) has attracted authors from various fields, given its relevance as a field of research. Among them, mathematical educators seek to understand the contributions HM can give to understand the nature of Mathematics and also how it can be used in teaching in order to promote rich and meaningful learning. In this process, the mathematics’ teacher is a key figure that it is important to know better, namely his conceptions, practices and training processes in HM. Objectives: To know the conceptions and practices of mathematics teachers participating in the TW on the use of HM in the teaching of the discipline, at the beginning of the training; understand the impact of training on the conceptions and practices on MH of the participating mathematics’ teachers. Methods: This study, which is developed in the context of a training workshop (TW), adopts a mixed methodology, based on an on-line questionnaire applied to 12 participating teachers in an TW on MH. Additionally, field notes and documentary records produced by teachers were used. Conclusion: The study allowed us to conclude that when teachers participate in (continuous) training that privileges rich tasks involving HM, framed in specific mathematical programmatic contents, in a reflective and collaborative environment and with experimentation in their practices, they tend to recognize the potentialities of the use of HM in teaching and to value them, introducing it in their practices.

Resumen Introducción: La Historia de las Matemáticas (HM) ha atraído a autores de diversos campos, dada su relevancia como campo de investigación. Entre ellos, los educadores matemáticos buscan entender las contribuciones que la HM puede hacer para entender la naturaleza de las matemáticas y también cómo se puede utilizar en la enseñanza con el fin de promover el aprendizaje rico y significativo. En este proceso, el profesor de matemáticas es una figura clave que es importante conocer mejor, a nivel de sus concepciones, prácticas y procesos de formación en HM. Objetivos: Conocer las concepciones y prácticas de los profesores de matemáticas que participan en la formación sobre el uso del HM en la enseñanza de la disciplina, al comienzo de la formación; comprender el impacto de la formación en los diseños y prácticas de los profesores de Matemáticas participantes en HM. Métodos: El estudio, que se desarrolla en el contexto de un taller de formación (TF), adopta una metodología mixta, basada en la recopilación de un cuestionario en línea a 12 profesores que participan en un TF en HM. Además, se utilizaron notas de campo y registros documentales producidos por profesores. Conclusión: El estudio nos permitió concluir que cuando los profesores participan en una formación (continua) que privilegia tareas ricas que implican HM enmarcadas en contenidos matemáticos programáticos específicos, en un entorno reflexivo y colaborativo y con experimentación en sus prácticas, tienden a reconocer las potencialidades del uso dela HM en la enseñanza y a valorarlos, presentándolos en sus prácticas.

Resumo Introdução: A História da Matemática (HM) tem atraído autores de diversas áreas, dada a sua relevância como campo de investigação. De entre eles, os educadores matemáticos procuram perceber os contributos que a HM pode dar para a compreensão da natureza da Matemática e também como ela pode ser usada no ensino, de modo a promover aprendizagens ricas e significativas. Neste processo, o professor de Matemática é uma figura-chave que importa conhecer melhor, ao nível das suas conceções, práticas e processos de formação em HM. Objetivos: Conhecer as conceções e as práticas dos professores de Matemática participantes na formação sobre a utilização da HM no ensino da disciplina, no início da formação; Compreender o impacto da formação nas conceções e nas práticas dos professores de Matemática participantes, sobre HM. Métodos: O estudo, que se desenvolve no contexto de uma oficina de formação (OF), adota uma metodologia mista, assentando a recolha na aplicação de um questionário on-line a 12 professores participantes numa OF sobre HM. Para além disso, recorreu-se a notas de campo e registos documentais produzidos pelos professores. Conclusão: O estudo permitiu concluir que quando os professores participam em formação (contínua) que privilegia tarefas ricas que envolvem HM enquadrada em conteúdos programáticos matemáticos específicos, num ambiente reflexivo e colaborativo e com experimentação nas suas práticas, tendem a reconhecer as potencialidades do uso da HM no ensino e a valorizá-las, introduzindo-a nas suas práticas.

Resumo O humor tem uma aceitação crescente, por se lhe reconhecer contributos positivos para o bem-estar das pessoas, em contextos como a saúde e as empresas. O que acontece na Educação, em particular, no ensino da Matemática? Na procura desta resposta, desenhamos este estudo, de natureza quantitativa, com uma amostra de 1088 professores de Matemática (portugueses e espanhóis). Com recurso a inquérito, averigua se professores que ensinam Matemática, ao longo dos diversos níveis de ensino, apreciam o humor, que perspectiva têm dele e do seu valor educativo e se o utilizam no ensino. O estudo averigua, ainda, se o nível de ensino em que lecionam tem influência na perceção e uso do humor com fins instrucionais. O estudo procura verificar se há diferenças significativas entre os professores portugueses e espanhóis em relação a estes aspectos. Os resultados revelam que a maioria dos professores, de todos os níveis de ensino, reconhecem o significado de humor, consideram que têm sentido de humor, justificam o seu uso no ensino da Matemática e já o viram utilizar ou utilizam nas aulas, com o objetivo de criar bom ambiente de aprendizagem e de fazer pensar os alunos. O estudo revela diferenças entre os professores dos diversos níveis de ensino, indicando que existe maior predisposição dos professores dos Anos Iniciais, comparativamente com os demais, para valorizar e utilizar o humor no ensino. O estudo revela também diferenças entre professores portugueses e espanhóis, sendo os portugueses a apresentarem uma média de concordância superior na generalidade dos itens.

Abstract At present, humour has an increasing acceptance and appreciation, because we recognize the positive contributions to the well-being of people in contexts as diverse as health, business, and entertainment. What happens in Education and, in particular, in Mathematics teaching? To answer this question, we designed this quantitative study with a sample of 1088 Iberian mathematics teachers (Portuguese and Spanish), that teach from the early years through to higher education. Through the use of a questionnaire, we seek to find out if Portuguese and Spanish teachers who teach Mathematics, throughout the various levels of education, appreciate humor, what perspective they have of it and its educational value, and if they use it in teaching the discipline. The study also sought to determine if the teaching level in which teachers teach mathematics has an influence on the perception and use of humor for instructional purposes. The study also investigates if there are any significant differences between Portuguese and Spanish teachers in relation to these aspects. The results show that the overwhelming majority of teachers, at all levels of teaching, recognize the meaning of humor, consider that they have a sense of humor, justify its use in mathematics teaching and have already seen it being used or used it in their classes, with the goal of creating a good learning environment and making students think. The study reveals differences among teachers at different levels of teaching, indicating that there is a greater predisposition of teachers in the initial years, in comparison to other years, to value and use humor in mathematics teaching. The study also reveals differences between Portuguese and Spanish teachers, with Portuguese presenting a higher average agreement in most items.

ABSTRACT The objective of this study was to investigate the effects of slaughter body weight (SW) on the performance, carcass characteristics, and meat quality of Jersey bulls in feedlots from weaning to slaughter. Eighteen Jersey bulls (125.7±15.9 kg; 5±0.6 months old) were used in the study. The treatments corresponded to three slaughter-weights: L360 – light weight, SW of 360 kg, M390 – medium weight, SW of 390 kg, and H420 – heavy weight, SW of 420 kg (n = 6/treatment); the animals were slaughtered at 368, 392, and 422 kg, respectively. The average daily gain was not influenced by SW. The M390 and H420 groups remained in feedlot, on average, 6 and 51 d longer, respectively, to reach a similar SW in relation to the L360 group. The increase in SW did not influence dry matter intake. However, the L360 group exhibited greater dry matter intake relative to body weight compared with the other two groups (29 vs. 26 g/kg). The increase in SW resulted in heavier and longer carcasses, with higher hot carcass yields. However, animals with greater SW had lower fat thickness. In addition, the increase in SW led to greater pistol cut, bone, and muscle weight for the carcasses. Although the meat color of Jersey bulls was darker in the H420 group, the meat was considered softer and more palatable by the consumer panel compared with the meat from the L360 group. The L360 group exhibited less fluid loss during thawing and cooking. Shear force measured by Warner Blatzer Shear was lower for H420. Animals slaughtered in the L390 group had an intermediate carcass weight, similar carcass yield, better cover fat and meat quality (color and shear) than animals slaughtered in the H420. Combining these factors with a shorter feedlot time compared with that of heavier animals, the SW of feedlot Jersey bulls is recommended at 390 kg.

RESUMO: Os efeitos da suplementação energética e da ervilhaca (Vica sativa L.) foram estudados para avaliar o perfil de ácidos graxos intramusculares de novilhos terminados em pastagens de aveia (Avena sativa L.). Foram avaliados 18 novilhos mestiços com 21 meses de idade. O experimento foi realizado em três tratamentos e seis repetições: pastagem de aveia (OA), pastagem de aveia + ervilhaca (OA + VET) e pastagem de aveia + suplementação (OA + SUP). A suplementação compreendeu a adição de fubá na dose diária de 1% do peso corporal dos animais. Os novilhos que receberam suplementação apresentaram maior teor lipídico no Longissimus lombar do que aqueles alimentados com OA + VET (1,25 contra 1,02%), enquanto aqueles alimentados com AO (1,15%) apresentaram valores intermediários. Os níveis de ácido linoléico conjugado foram maiores em novilhos alimentados com AO (0,57%) e OA + SUP (0,59%), enquanto a maior quantidade de ácidos graxos ômega-3 foi observada em animais alimentados com OA + VET (3,32%). Animais terminados em pastagens sem suplementação apresentaram menor proporção de n-6: n-3 (3,14). Novilhos terminados em pastagem de aveia com ervilhaca apresentaram gordura intramuscular mais saudável do que aqueles terminados com suplementação de milho moído, uma vez que apresentaram maior quantidade de PUFAs e melhor a relação n-6: n-3.

ABSTRACT: The effects of energetic supplementation and mixture vetch (Vica sativa L.) were studied to evaluate the intramuscular fatty acid profile of steers finished on oat (Avena sativa L.) pastures. Eighteen 21-month-old crossbred steers were evaluated. The experiment was carried out in three treatments and six repetitions: oat pasture (OA), oat pasture + vetch (OA + VET), and oat pasture + supplementation (OA + SUP). Supplementation comprised the addition of corn meal at a daily dose of 1% of the animals’ body weight. Steers receiving supplementation had higher lipid content in Longissimus lumborum than did those fed with OA + VET (1.25 vs 1.02%), whereas those fed with OA (1.15%) showed intermediate values. Conjugated linoleic acid levels were higher in steers fed OA (0.57%) and OA + SUP (0.59%), whereas the highest amount of omega-3 fatty acids was observed in animals fed OA + VET (3.32%). Pasture-finishing without supplementation resulted in a lower ratio of n-6:n-3 (3.14). Steers finished in oat mixture with vetch showed healthier intramuscular fat than did those finished with cornmeal supplementation; importantly, the higher the amount of PUFAs, the better n-6:n-3 ratio.

ABSTRACT This study was performed to determine and quantify the inherent auction factors that affect the selling price of beef calves (weanlings - from six to nine months old). Data on the selling price, location and month of the auction, genetic group, lot size live weight, and sex of animals were collected in 148 auctions from January 2004 to December 2014. A total of 4,312 lots corresponding to 48,588 calves were classified into seven genetic groups according to their phenotypic characteristics. The values were deflated using the General Price index (IGP-DI) inflation index and met the parametric assumptions. The selling price was standardized by the yearly median, assuming that its value corresponds to 100%, and the other values varied in their function. Path analysis quantified the direct and indirect effects of the variables taken as explanatory of the selling price, followed by regression analysis and Tukey test. Overall, the direct effect of the average weight was the highest (0.7), followed by sex (0.38). The smallest direct effect was the genetic group (−0.075). There was a growing exponential relationship between average weight of the lot and selling price and a decreasing ratio between price per kilo and the average weight of the lot (−0.0003 percentage points per kilogram). Males were generally 15.7% more valued than females. The British × Zebuine crossbreed was the most valued breed, followed by the British breed (8.9 and 3.6%, respectively). The highest premium was in November, followed by February (9.57 and 8.84%, respectively, compared with median year). The selling price increases linearly by 0.3284 percentage points for each additional animal in the lot. The average weight of the lot was found to be the most important variable in the formation of the selling price, followed by the sex of the animals.

RESUMO Associa-se o desempenho do Ensino Médio, estagnado há mais de década, ao conjunto de insuficiências da Educação de Base. Cogita-se a necessidade de se rever recente lei que altera a LDB, assim como de se reelaborar em seu conjunto a Base Nacional Comum Curricular, para poder ser sintética e efetiva referência educacional. Sugere-se melhor distribuição dos recursos fiscais e apoio logístico aos municípios para que possam de fato responder pelo início da escolarização. Propõe-se uma carreira em que professores possam progredir sem deixar de lecionar, tornando-se tutores na formação prática de futuros colegas.

ABSTRACT Senior high school performance, stagnated for more than ten years, is related to a general insufficiency of basic education. A recent law that changes the national education law needs to be reviewed together with the common core curriculum in order to become a synthetic educational reference. Better distribution of tax revenues is suggested, as well as logistical support to the counties, so that they can really be held accountable for primary schooling. A teachers’ career program is proposed so that they may progress without ceasing to teach, and become tutors in the practical training of futures colleagues.

Resumo As discussões matemáticas constituem uma forma poderosa para promover a aprendizagem dos alunos ao favorecerem a apresentação, justificação, argumentação e sistematização dos raciocínios associados ao trabalho com tarefas matemáticas. O professor desempenha um papel preponderante na condução da discussão, sendo chamado a realizar um conjunto de ações de ensino, tendo por base o seu conhecimento didático. Neste artigo apresentamos as práticas de discussão de dois professores de Matemática do 8.° ano de escolaridade, com o objetivo de compreender como conduzem discussões em tópicos de Álgebra. O estudo é qualitativo interpretativo e baseia-se no estudo de caso de dois professores, que integram um grupo colaborativo. Os resultados mostram que os professores estruturam a discussão matemática em três momentos principais e gerem o discurso com vista à generalização de ideias algébricas. Para isso, empreendem um conjunto de ações de ensino que favorecem a apresentação, justificação e argumentação de diversas estratégias de resolução.

Abstract Mathematical discussions are a powerful activity for students’ learning by supporting the presentation, justification, argumentation, and systematization of the reasoning associated to the work on mathematical tasks. The teacher plays a fundamental role in leading the discussion, being called to carry out a set of instructional actions, based on his/her didactic knowledge. In this paper, we present discussions practices of two 8th grade mathematics teachers, in order to understand how they use discussions when teaching algebra topics. The study is qualitative and interpretive and is based on the case study of two teachers, who are part of a collaborative group. The results show that the teachers structure the mathematical discussion at three main moments and manage the discourse for the generalization of algebraic ideas. Thereby, they undertake a set of instructional actions that help the presentation, justification, and argumentation of several solution strategies.

Resumo A prova é uma atividade que desempenha um papel fundamental na construção do conhecimento matemático, razão pela qual adquire relevância nos programas escolares de Matemática. Admitindo que as conceções dos professores sobre a prova afetam a forma como ela é tratada em sala de aula, procuramos averiguar as conceções de professores portugueses de Matemática do 3.° ciclo do Ensino Básico (do 7.° ao 9.° ano) sobre diferentes aspetos da prova matemática e a influência que a experiência profissional tem nessas conceções. Adotando uma abordagem metodológica mista, recolhemos os dados através de um questionário, respondido por 72 professores, e de uma entrevista a duas professoras com experiências profissionais diferentes. Os resultados revelam que os professores, sobretudo os que têm menos tempo de docência, consideram que a prova matemática tem uma natureza distinta da de outras disciplinas, é uma atividade essencial para a construção do conhecimento matemático, tem como função verificar e explicar a veracidade de uma afirmação e permite desenvolver o raciocínio e a comunicação matemática. No que respeita à participação dos alunos na atividade de provar, são os professores com mais tempo de docência que mais o destacam, o que permite aos alunos perceberem a natureza desta atividade. Em termos curriculares, são os professores com menos experiência docente que mais concordam com a presença da prova logo nos primeiros anos, embora salientem que esta atividade só faz sentido em alguns tópicos programáticos.

Abstract Proof is an activity that plays a key role in the construction of mathematical knowledge, which is why it acquires relevance in mathematics programs. Admitting that teachers' conceptions about proof influence how it is handled in the classroom, we tried to investigate the conceptions of Portuguese mathematics teachers from the 3rd cycle of basic education (grade 7 to 9) on different aspects of mathematical proof and the relationship that the teachers' experience has in these conceptions. Adopting a mixed methodological approach, we collected data through a questionnaire answered by 72 teachers, and an interview with two teachers with different professional experience. The results show that teachers, especially those with less experience, consider that mathematical proof has a distinct nature from other disciplines, it is an essential activity for the construction of mathematical knowledge and its function is to verify and explain the truth of a statement by developing reasoning and mathematical communication. With respect to student participation in the activity of proving, teachers with more teaching experience are the ones that most highlight it, which allows students to realize the nature of this activity. In curriculum terms, teachers with less experience are the ones that most agree with the presence of proof in early grades, while emphasizing that this activity only makes sense in some program topics.

Cet article discute la manière dont une future enseignante de mathématiques développe et mobilise son savoir didactique, au niveau de la connaissance tant du contenu mathématique que pédagogique, au cours de la préparation et l'analyse de tâches de modélisation mathématique qui font appel à la technologie. Ce travail s'est fait à la fin de sa formation initiale, au moment de la réalisation du stage professionnel. Il s'agit d'une étude interprétative, sous la forme d'une étude de cas qualitative. La conclusion est que l'exécution, pendant le stage, de tâches (accompagnées de réflexion) de modélisation mathématique, qui utilisent la technologie, favorise le développement professionnel des futurs enseignants. Sont ainsi développées les connaissances sur le contenu mathématique, en activant les acquis de la formation initiale, ainsi que celles au niveau pédagogique. Les tâches de modélisation ont permis au stagiaire de comprendre qu'il existe, en plus le modèle transmissif, d'autres modèles d'enseignement d'orientation exploratoire. Le professeur propose alors des tâches mathématiques plus ouvertes, de degré de difficulté plus élevé, dans lesquelles les élèves s'investissent dans une activité mathématique intense, ce qui peut permettre des apprentissages mathématiques significatifs.

Este artigo discute a forma como uma futura professora de Matemática mobiliza e desenvolve o seu conhecimento didático, ao nível do conhecimento do conteúdo matemático e do conhecimento da prática letiva, na preparação e análise de tarefas de modelação matemática, recorrendo à tecnologia. Este trabalho foi desenvolvido na fase final da sua formação inicial, no momento em que realiza o seu estágio profissional. Trata-se de um estudo interpretativo, na forma de estudo de caso qualitativo, que mostra que a realização de tarefas de modelação matemática e a sua reflexão, recorrendo à tecnologia, durante o estágio profissional, constitui uma ocasião de desenvolvimento profissional da futura professora, tanto em relação ao seu conhecimento do conteúdo matemático, ao ativar conhecimento trabalhado durante a sua formação inicial, como do seu conhecimento instrucional. Desta forma, as tarefas de modelação permitiram que a estagiária compreendesse que, para além do modelo transmissivo, existem outros modelos de ensino, com um cunho exploratório, que passam pela proposta pelo professor de tarefas matemáticas abertas e com um grau de dificuldade mais elevado, que envolvem os alunos numa atividade matemática intensa e que podem redundar em aprendizagens matemáticas significativas.

This article discusses how a preservice teacher of mathematics develops and mobilizes their didactical knowledge, in the matter of mathematical content and of instructional knowledge, in the preparation and analysis of tasks of mathematical modeling, using technology. The work took place at the end of their initial education when they make their internship. It is an interpretive study in the form of a qualitative case study that shows that the performance of tasks of mathematical modeling and the thinking about it, using technology, during the internship it is an opportunity for professional development of the preservice teacher, both the level of their knowledge of the mathematical content, enabling knowledge worker during their initial training, as their instructional knowledge. At this level, the modeling task allowed the future teacher to understand that beyond the transmissive model, there are other models of teaching in an exploratory nature, in which the teacher proposes mathematical open tasks with a higher degree of difficulty, involving students in mathematical intense activity which may result in significant mathematics learning.

El presente artículo aborda cómo una futura profesora de matemáticas moviliza y desarrolla sus conocimientos didácticos, en lo que se refiere al conocimiento del contenido matemático y al conocimiento pedagógico, en la preparación y análisis de tareas de modelación matemática recurriendo a la tecnología. Este trabajo se desarrolló durante la fase final de su formación académica, en el momento de la realización de las prácticas. Se trata de un estudio interpretativo, bajo la forma de estudio de caso cualitativo, que demuestra que la realización de tareas de modelación matemática y la reflexión sobre ellas, recurriendo a la tecnología, durante la fase de prácticas constituye una oportunidad de desarrollo profesional para la futura profesora, tanto en lo que tiene que ver con su conocimiento del contenido matemático, activando conocimiento adquirido durante su formación académica, como en lo relativo a su conocimiento pedagógico. En este sentido, las tareas de modelación han permitido que la profesora en prácticas entendiese que, además del modelo transmisivo, existen otros modelos de enseñanza con un carácter exploratorio que pasan por que el profesor proponga tareas matemáticas más abiertas y con un grado de dificultad mayor, que hacen partícipes los alumnos en una actividad matemática intensa y que pueden redundar en aprendizajes matemáticos significativos.

O objetivo deste estudo foi avaliar os órgãos internos e o trato digestório de novilhos e vacas de descarte 5/8 Charolês (Ch) 3/8 Nelore (Ne) e 5/8Ne 3/8Ch, terminados em confinamento. Foram utilizados 12 novilhos e 12 vacas de descarte, sendo cada categoria composta por seis animais 5/8Ch 3/8Ne e seis animais 5/8Ne 3/8Ch. A idade média dos animais ao final do período experimental foi de 23 meses para os novilhos e 68 meses para as vacas de descarte. Os animais foram terminados em confinamento até atingirem acabamento para o abate. A dieta alimentar continha relação volumoso:concentrado de 40:60 (base na matéria seca). O delineamento experimental foi o inteiramente casualizado, em um arranjo fatorial 2 x 2 (2 categorias x 2 grupos genéticos. Os dados foram submetidos à análise de variância pelo proc GLM, sendo as médias classificadas pelo teste "F" e os parâmetros com efeito significativo para interação entre categoria e grupo genético comparados pelo "teste t", a 5% de significância. Houve maior peso de abate (PAB) (509,67 contra 414,50 kg) e de corpo vazio (PCVZ) (433,01 contra 355,27 kg, respectivamente) para as vacas em relação aos novilhos. As vacas apresentaram maiores pesos absolutos para coração (1,62 contra 1,40 kg), fígado (7,07 contra 5,95 kg) e também para o conjunto de órgãos internos, total do trato digestório e sangue. Quando os pesos dos componentes foram expressos em porcentagem do PCVZ, os novilhos foram superiores no peso dos pulmões (1,08 contra 0,95%), baço (0,29 contra 0,22%), intestinos (2,04 contra 1,72%) e no total dos órgãos vitais (3,92 contra 3,63%). Quanto aos grupos genéticos, animais 5/8Ch 3/8Ne apresentaram maior peso absoluto de trato digestório. Não houve correlação entre o rendimento de carcaça com componentes não integrantes da carcaça expressos em peso absoluto. Vacas de descarte apresentam maior massa dos órgãos internos e do trato digestório que novilhos abatidos aos 24 meses, enquanto bovinos do grupo genético 5/8Ch 3/8Ne apresentam maior peso de compartimentos e do total do trato digestório em relação a bovinos 5/8Ne 3/8Ch.

The objective of this study was to evaluate the internal organs and digestive tract of two categories, steers and cull cows, from two genetic groups: 5/8 Charolais (Ch) 3/8 Nellore (Ne) and 5/8Ne 3/8Ch, finished in feedlot. We used 12 steers and 12 cull cows, being the categories compounded for six 5/8Ch 3/8Ne animals and six animals 5/8Ne 3/8Ch. The average age of animals at the end of the experimental period was 23 and 68 months for steers and cull cows, respectively. The animals were feedlot-finished until reaching finishing degree for slaughter. The experimental diet had a roughage:concentrate ratio of 40:60 (dry matter basis). The experimental design was completely randomized in a 2 x 2 (two categories and two genetic groups) factorial scheme. Data were submitted to analysis of variance by proc GLM, being the means classified by test "F" and the parameters with significant effects for interaction between genetic group and category compared by "test t", with 5% significance level. Slaughter weight (SW) (509.67 versus 414.50kg) and empty body weight (EBW) (433.01 versus 355.27kg, respectively) were higher for cows in relation to steers. The cull cows showed higher absolute weight for heart (1.62 versus 1.40 kg), liver (7.07 versus 5.95 kg) and for total internal organs, digestive tract and blood. When the components were adjusted for percentage of EBW the steers were superiors on lungs (1.08 versus 0.95%), spleen (0.29 versus 0.22%) intestines (2.04 versus 1.70%) and total internal organs weight (3.91 versus 3.60%). As genetic groups, 5/8Ch 3/8Ne animals showed higher absolute weight for digestive tract. The carcass dressing percentage and non-carcass components, in absolute weight, showed correlation. Cull cows showed higher weight for internal organs and digestive tract than steers slaughtered at 24 months, while cattle for genetic group 5/8Ch 3/8Ne showed higher weight for compartments and total of digestive tract in relation to 5/8Ne 3/8Ch bovines.

O Brasil sacrifica muitos bezerros de origem leiteira ao nascer, o que pode se tornar um problema mercadológico bastante sério. O objetivo deste experimento foi avaliar a composição física da carcaça e as características qualitativas da carne de bezerros holandeses terminados em confinamento ou em pastagem com suplementação, abatidos aos 140; 180; 220 ou 260 kg de peso corporal. No início da terminação, os bezerros apresentavam em média 57 kg e 58 dias de idade. Os animais confinados foram alimentados com volumoso (silagem de milho) e concentrado, na proporção de 40:60 e os da pastagem suplementados com concentrado a 1% do peso corporal. O delineamento experimental foi o inteiramente casualizado, em arranjo fatorial 2 x 4 (dois sistemas de terminação x quatro pesos de abate). Foi observada interação significativa entre peso de abate e sistema de terminação somente para a textura da carne. Os animais terminados em pastagem apresentaram melhor textura com o aumento do peso, enquanto que os animais confinados o peso não influenciou. Animais terminados a pasto apresentaram maior percentagem de músculo (69,48% contra 66,57%), menor percentagem e quantidade de gordura (9,58% e 9,75 kg contra 13,20% e 13,08 kg respectivamente) em relação aos animais do confinamento. Houve crescimento linear para a quantidade total de músculo, osso e gordura, relação músculo/osso, relação porção comestível/osso, palatabilidade e suculência quando se elevou o peso de abate. O percentual de osso e a cor da carne decresceram linearmente com o aumento do peso de abate. A percentagem de músculo e gordura apresentaram comportamento quadrático. Os animais de raças leiteiras são excelentes produtores de carne magra, com boa maciez, palatabilidade e suculência.

The Brazil sacrifices many dairy calves at birth, which can become a very serious problem merchandising. The objective of this experiment was to evaluate the physical carcass composition and meat quality characteristics of Holstein calves in feedlot or pasture with supplementation, slaughtered at 140, 180, 220 or 260 kg body weight. In the early termination calves had on average 57 kg and 58 days of age. The confined animals were fed forage (corn) and concentrated, in the ratio of 40:60 and concentrated pasture supplemented with 1% body weight. The experimental design was completely randomized in a factorial 2 x 4 (two feeding systems x four slaughter weights). It was observed a significant interaction between slaughter weight and finishing system only for the texture of the meat. The finished animals on pasture showed improved texture with increased weight, whereas the confined animals did not affect the weight. Animals finished on pasture had higher muscle percentage (69.48% vs 66.57%), and lower fat percentage (9.58% and 9.75 kg vs 13.20% and 13.08 kg) compared to confined animals. There was a linear increase in the total amount of muscle, bone and fat, muscle / bone ratio, compared edible portion / bone, palatability and juiciness when increased slaughter weight. The percentage of bone and meat coloring decreased linearly with the increase of slaughter weight. The proportion of muscle and fat, showed quadratic behavior. The animals of dairy breeds are excellent producers of lean meat, with good smoothness, flavor and juiciness.

The relation between temperament with performance and meat quality was determined in 79 Charolais × Nellore steers kept in feedlot. Temperament was evaluated according to exit velocity, scale composite score and flight distance four times in the finishing phase, along with body weight, intake and feed conversion measures. Cattle were classified as calm, intermediate and excited according to exit velocity measures at the beginning of the trial. Excited cattle presented larger values for composite score and flight distance. Irrespective of genotype, excited cattle presented lower average daily gain, dry matter intake and worse feed conversion. Temperament categories did not affect most of beef quality traits, except for calm Bos indicus steers, which presented greater pH measured 1 hour post mortem compared with more reactive steers. However, moderate but negative correlations were detected between exit velocity, flight distance and composite score and beef quality as well as Warner-Bratzler shear value, luminosity, pH measured 24 hours post mortem, although they were not consistent between genotypes raised under the same conditions.

The objective of the experiment was to study the carcass physical composition and meat qualitative characteristics of different categories of Charolais cattle, feedlot finished. Nine steers (ST), ten heifers (HE), with average age of 20 months, and ten cull cows (CO) with average age of 87 months, taken from the same herd, were used. Diet contained 13% of crude protein for ST and HE and 10% for CO, with roughage:concentrate relation of 50:50, on a dry matter basis. The animals of the three categories were slaughtered with similar degree of finishing, with average subcutaneous fat thickness of 3.8 mm. HE showed carcasses with greater pistolcut percentage (52.8%) than ST (51.0%) and CO (51.4%). The carcass physical composition was similar among the categories evaluated, with 66.5; 67.0 and 67.3% of muscle, 19.1; 18.5 and 18.7% of fat, and 14.9; 15.0; and 14.6% of bone, respectively, for ST, HE and CO. The marbling score was lower for HE (4.6 points) than ST (7.1 points) and CO (6.5 points). However, when this characteristic was adjusted for 100 kg of cold carcass, the means were similar among the categories. CO showed higher cooking losses (27.8%) than ST (21.4%) and HE (23.5%). Meat color, texture, tenderness, shear force, palatability and juiciness were similar among the categories. Charolais cows have the potential for the production of carcass and meat with quality similar to steers and heifers.

In order to evaluate the effect of the different percentages of zebu blood in the genotype of crossbred steers on carcass traits, a meta-analysis was carried out, using 30 studies conducted in Brazil that have been published since the year 2000. The parameters evaluated were hot carcass weight (221 estimates), cold carcass weight (232), hot carcass (236) and cold carcass yield (223), subcutaneous fat thickness (238) and the percentages of saw cut (233), forequarter (234) and sidecut (246 estimates). Initially, exploratory analysis was performed for each of the variables for detection of publication vices through the dispersion of observations by pointing out the outliers eliminated. Normality tests were normal and the data were subjected to analysis of variance for the regression study, which were assessed to the third degree. Weights of hot carcass and cold carcass, hot and cold carcass yield and the percentage of saw cut had a quadratic effect on animals with the presence of zebu blood, indicating superiority of crossbred animals. The regression equation showed that 66; 50; 72; 81 and 59% of zebu in crossbred animals showed higher hot and cold carcass weight, hot and cold carcass percentage and saw cut, respectively. Fat thickness was not influenced by the degree of zebu in the genotype. The percentage of forequarter has a positive response by increasing the degree of zebu in the genotype, while the sidecut has a negative answer. The crossbreeding between zebu and European breeds provides carcasses with better quality than purebred animals.