Avaliação econômica da terminação de bovinos de corte em pastagem irrigada / Economic evaluation of finishing beef cattle on irrigated pasture

Foi avaliada a viabilidade econômica de três sistemas de produção por meio da mensuração dos custos de produção e da análise dos indicadores financeiros. Os três sistemas (S1, S2 e S3), situados na fronteira oeste do Rio Grande do Sul, foram avaliados no período de outubro de 2010 a outubro de 2011. A pastagem estabelecida no S1 foi de azevém (Lolium multiflorumLam)e trevo branco (Trifolium repensLam); no S2, trevo branco, trevo vermelho (Trifolium pratenseLam), cornichão (Lotus corniculatusLam), azevém e aveia preta (Avena strigosaSchreb); e no S3, azevém, cornichão, trevo branco e trevo vermelho. Os animais foram pesados na entrada e na saída das pastagens. A coleta de dados para mensuração do custo foi realizada mensalmente utilizando-se planilhas apropriadas. As produtividades foram de 369, 772 e 637kg/ha para os sistemas S1, S2 e S3, respectivamente. O S2 apresentou o maior custo total (R$ 2.101,59/ha), enquanto o menor foi obtido pelo S1 (R$ 1.626,93/ha). Na análise do custo operacional médio dos três sistemas, os itens que apresentaram maiores valores foram a implantação de pastagem, a energia elétrica, a manutenção da pastagem e a depreciação. Quanto às margens, os sistemas S1, S2 e S3 apresentaram, respectivamente, R$ 33,46, 1.162,55 e 701,01/ha para margem bruta; R$ -63,51, 955,40 e 541,05/ha para margem operacional; e R$ -583,18, 291,61 e -28,99/ha para lucro total. A rentabilidade foi de -0,47, 4,37 e 3,01% e a lucratividade foi de -5,94, 39,92 e 27,38% para o S1, S2 e S3, respectivamente. A irrigação de pastagens para terminação de bovinos é viável economicamente, no entanto a sua adoção deve sempre visar a altas produtividades zootécnicas devido ao seu elevado custo de produção.

The economic viability of three systems of production was evaluated through the measurement of costs and analysis of financial indicators. The three systems (S1, S2 and S3), located on the Western Border of Rio Grande do Sul, were evaluated from October 2010 to October 2011. The pasture established is S1 was ryegrass (Lolium multiflorum Lam) and white clover (Trifolium repens Lam), in S2, white clover, red clover (Trifolium pratense Lam), Bird's-foot trefoil (Lotus corniculatus Lam), ryegrass and oats (Avena strigosa Schreb), and in S3, ryegrass, birdsfoot trefoil, white clover and red clover. The animals were weighed before and after the pastures. Data collection was conducted monthly, using spreadsheets suitable for the measurement of production cost. Productivities were 369, 772 and 637 kg/ha for systems S1, S2 and S3, respectively. S2 had the highest total cost (R$ 2101.59/ha), while the lower was obtained by S1 (R$ 1626.93/ha). In the analysis of the average operating costs, items that showed the highest values were the establishment of pasture, electricity, maintenance of pasture and depreciation. As for margins, the systems S1, S2, and S3 were, respectively, R$ 33.46, 1162.55 and 701.01/ha for gross margin; R$ -63.51, 955.40 and 541.05 ha-1 for operating margin; and R$ -583.18, -28.99 and 291.61 ha-1 for total profit. The return was -0.47, 4.37 and 3.01% and profitability was -5.94, 39.92 and 27.38% for the S1, S2 and S3 respectively. The positive result found in the financial evaluation of the three systems studied indicates the economic viability of irrigated pasture in finishing cattle. Irrigation of pasture for finishing cattle is economically feasible, however, its application should always aim high yields husbandry due to their high cost of production.

Ultrastructural study of the denervated diaphragm in rats / Estudio ultraestructural del diafragma desnervado en ratas

The structural alterations that occur in the muscle fibers of denervated rat diaphragms were studied. Fifteen adult male albino rats (Rattus norvegicus) with a mean weight of 200 g and about 60 days of age were used. Chronically denervated diaphragms were obtained and the animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by sectioning of the phrenic nerve and the right antimere served as control. Each antimere was divided into fragments, which were used for analysis transmission electron microscopy. During the initial phase of denervation (4 weeks), ultrastructural muscle modifications appeared in scattered fibers and in foci along these fibers. Muscle fibers with foci of less dense and loosely arranged myofibrils, disorganized Z line, displaced T tubules, and central nucleus exhibiting reentrances and fragmented aspect were observed. After 8 weeks, formation of large aggregates of small elongated mitochondria showing altered cristae, matrix inclusions and increased electron density was noted. At 12 weeks of denervation the alterations were found to be more drastic. Nuclei with internal deposits of myofibrillar or amorphous material were observed. In these fibers, vacuoles harbored enormous myeloid structures in the subsarcolemmal or intermyofibrillar region.

Fueron estudiadas las alteraciones ultra estructurales de las fibras musculares del diafragma denervado de ratas. Fueron utilizadas 15 ratas albinas (Rattus norvegicus), machos, adultas, con peso promedio de 200 g de aproximadamente 60 días de edad. Los diafragmas crónicamente denervados fueron obtenidos después de 4, 8 y 12 semanas de denervación. El antímero izquierdo del diafragma fue denervado por sección del nervio frénico y el antímero derecho fue utilizado como control. Cada antímero fue dividido en fragmentos, que fueron utilizados para el estudio en microscopia electrónica de transmisión. Durante los períodos iniciales de denervación (4 semanas), las modificaciones en la ultraestructura del músculo se disponen en fibras dispersas y en focos a lo largo de las mismas. Se observan fibras musculares con focos de miofibrillas rarefactas y laxamente dispuestas; línea Z desorganizada; túbulos T dislocados; núcleo central con aspecto fragmentado. Después de 8 semanas de denervación, se observa la formación de numeroso agregados de pequeñas mitocondrias alargadas, con alteraciones en las crestas, inclusiones en la matriz y aumento de la electrodensidad. Con 12 semanas de denervación, las alteraciones se muestran más drásticas; se observan núcleos con depósitos internos de material miofibrillar o amorfo. En estas fibras, las vacuolas presentan grandes estructuras mieloides en la región subsarcolemal o intermiofibrillar.

Morphologic alterations resulting from denervation of the diaphragm in rats / Alteraciones morfológicas resultantes de la denervación del diafragma en ratas

The morphological alterations that occur in the muscle fibers of denervated rat diaphragms were studied. Fifteen adult male albino rats (Rattus norvegicus) with a mean weight of 200 g and about 60 days of age were used. Chronically denervated diaphragms were obtained and the animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by sectioning of the phrenic nerve and the right antimere served as control. Each antimere was divided into two fragments, which were used for histological (H.E.) and histoenzymological (NADH-TR and myofibrillar ATPase). After 4 weeks, denervated muscle fibers showed important light microscopic alterations: atrophy with angular profiles in cross-sections, cytoplasm containing vacuoles, enlarged interstitial space with increased connective tissue, cellular infiltration, and muscle fibers without defined contours. The most marked alterations being observed for type IIb and IIa fibers. Eight and 12 weeks after denervation, the NADH-TR reaction showed that it was impossible to characterize the muscle fibers based on their metabolic profile...

Fueron estudiadas las alteraciones morfológicas de las fibras musculares del diafragma denervado de ratas. Se utilizaron 15 ratas albinas (Rattus norvegicus) machos, adultos, con peso promedio de 200g y cerca de 60 días de edad. Se denervó el diafragma y después de 4, 8 y 12 semanas los animales fueron sacrificados. El antímero izquierdo del diafragma fue denervado por sección del nervio frénico y el antímero derecho fue utilizado como control. Cada antímero fue dividido en fragmentos, utilizados para el estudio histológico (H-E), histoenzimológico (NADH-TR y ATPasa miofibrilar). Después de 4 semanas las fibras musculares denervadas presentaron alteraciones importantes en lamicroscopía de luz: atrofia con perfiles angulados en secciones transversales; citoplasma con vacuolas; aumento del espacio intersticial con aumento de tejido conjuntivo; infiltración celular y fibras musculares sin contornos definidos, siendo las alteraciones más marcadas en las fibras tipo IIb e IIa. Después de 8 y 12 semanas de denervación la reacción para NADH-TR demuestra que es imposible caracterizar a las fibras musculares a través de su perfil metabólico...

Morphometric and morphological analysis of neuromuscular junction alterations in the denervated rat diaphragm / Evaluación de las alteraciones morfológicas y morfométricas de las uniones neuromusculares del diafragma denervado en ratas

The morphological and structural alterations that occur in the neuromuscular junctions of the denervated rat diaphragm were studied. Fifteen adult male albino rats (Rattus norvegicus) aged about 60 days and with a mean weight of 200 g were used. Chronically denervated diaphragms were obtained and the animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by section of the phrenic nerve and the right antimere was used as control. Each antimere was divided into three fragments: one was used for histochemical (nonspecific esterase) and morphometric study of neuromuscular junctions, and the other two were used for transmission and scanning electron microscopy (SEM) analysis. Histochemical analysis of the diaphragm neuromuscular junctions after denervation showed only small changes in junction morphology. However, these junctions became smaller and elongated and presented less visible contours with increasing time of denervation. Ultrastructural analysis of neuromuscular junctions after 12 weeks showed more or less organized junctional folds on the muscle fiber surface. The junctional cytoplasm exhibited important alterations such as mitochondrial degeneration and the presence of numerous filaments. SEM revealed the presence of deep primary synaptic grooves with peripheral excavations which housed the nerve terminal boutons and exhibited internally the secondary synaptic clefts present among the junctional folds of the sarcolemma. This study showed that some of the morphological changes demonstrated in other denervated striated skeletal muscles are not repeated at the same intensity or in the same temporal pattern in the rat diaphragm.

En este trabajo se estudiaron las alteraciones morfológicas y estructurales de las uniones neuromusculares en el diafragma denervado de ratas. Se utilizaron 15 ratas albinas (Rattus norvegicus), machos, adultos, con peso promedio de 200g y cerca de 60 días de edad. Los diafragmas crónicamente denervados fueron obtenidos y los animales se sacrificaron después de 4, 8 y 12 semanas de denervación. El antímero izquierdo del diafragma fue denervado por sección del nervio frénico y el antímero derecho fue utilizado como control. Cada antímero fue dividido en 3 fragmentos: uno fue utilizado para el estudio histoquímico (esterasa inespecífica) y morfométrico. Los otros dos se destinaron al estudio de microscopía electrónica de transmisión (MET) y microscopia electrónica de barrido (MEB) de las uniones neuromusculares. El estudio histoquímico de las uniones neuromusculares posterior a la denervación, muestra que la morfología de esas uniones sufre pequeñas alteraciones. Con la evolución del tiempo de denervación esas uniones muestran tamaños menores, son alargadas y con contornos menos nítidos. La ultra-estructura de las uniones neuromusculares después de 12 semanas, demostró que la superficie de la fibra muscular exhibe pliegues de unión más o menos organizados. La región del citoplasma de unión exhibe alteraciones importantes, con degeneración mitocondrial y presencia de muchos filamentos. En MEB se observa que los botones sinápticos primarios son profundos, presentan escavaciones periféricas donde estaban alojados los botones de las terminaciones nerviosas y exhiben internamente, los espacios sinápticos secundarios presentes entre los pliegues de unión del sarcolema. Este estudio mostró que algunos patrones morfológicos demostrados en otros músculos estriados esqueléticos denervados no se repiten con la misma intensidad y curso temporal en el diafragma de ratas.

Dispneia da asma bronquica (revendo um velho conceito). / Dyspnea in bronchial asthma (reviewing an old concept)

Por intermedio de inquerito efetuado com 70 pacientes asmaticos e 55 medicos em exercicio da pratica medica geral, identifica-se significativa divergencia entre os grupos, no tocante ao tipo de dispneia apresentada pelos individuos asmaticos.Enquanto os padecedores de asma revelam que predomina a dispneia inspiratoria (74,3%), os medicos analisam a dispenia como essencialmente expiratoria (70,9%). Observa-se ainda que os medicos, na sua maioria 70,9%), dao noticia que foram os livros ou o curso medico as fontes que determinavam a referencia de dispneias expiratoria. EM torno dos resultados do inquerito tecem-se comentarios de ordem fisiopatologica, alinham-se estudos recentes que apoiam o relato dos individuos com asma, ao declararem o predominio da dificuldade inspiratoria quando da dispneia