Nutritional value, total dry matter losses, effluent production and pollutant potential in Brachiaria brizantha cv. Paiaguás grass / [Valor nutricional, perdas totais de matéria seca, produção e potencial poluidor de efluentes em silagem de Brachiaria brizantha cv. Paiaguás]

The objective of the present study was to evaluate losses, production and polluting potential of the effluent, nutritional value and aerobic stability of silages of Brachiaria brizantha cv. Paiaguás grass, in different particle sizes and compaction density in silage. Three theoretical particle sizes (TTP 5; 8 and 12mm) and three compaction densities (DC 550; 600 and 650kg/m3) were evaluated, distributed in a factorial design (3 x 3), with four repetitions. The highest volume of effluent was found in silages with higher compaction densities (600 and 650kg/m3) and lower TTP (5 and 8mm). The highest chemical oxygen demand and biochemical oxygen demand were registered in the treatment with TTP of 5mm and higher DC (600 and 650kg/m3). Greater in vitro digestibility of DM was verified in the silage chopped at 5 and 8mm. There was no break in aerobic stability for 216 hours. Silage with a low compaction density 550kg/m3 and processing with a theoretical particle size of 12mm reduces effluent losses. In general, the nutritional value of Paiaguás grass was not influenced by the treatments. Different particle sizes and compaction density did not change the aerobic stability of silages.(AU)

Objetivou-se avaliar perdas, produção e potencial poluidor do efluente, valor nutricional e estabilidade aeróbia de silagens do capim Brachiaria brizantha cv. Paiaguás, em diferentes tamanhos de partícula e densidade de compactação na ensilagem. Foram avaliados três tamanhos teóricos de partícula (TTP 5; 8 e 12mm) e três densidades de compactação (DC 550; 600 e 650kg/m3), distribuídos em arranjo fatorial (3 x 3), com quatro repetições. O maior volume de efluente foi verificado nas silagens com maiores densidades de compactação (600 e 650kg/m3) e menores TTP (5 e 8mm). As maiores demanda química de oxigênio e demanda bioquímica de oxigênio foram registradas no tratamento com TTP de 5mm e nas maiores DC (600 e 650kg/m3). Maior digestibilidade in vitro da MS (média de 57,2%) foi verificada na silagem picada a 5 e 8mm. Não houve quebra da estabilidade aeróbia durante 216 horas. A ensilagem com baixa densidade de compactação (550kg/m3) e o processamento com tamanho teórico de partículas 12mm reduzem as perdas por efluente. O valor nutricional da silagem de capim-paiaguás, em geral, não foi influenciado pelos tratamentos. Diferentes tamanhos de partícula e densidade de compactação não alteraram a estabilidade aeróbia das silagens.(AU)

Soil compaction on traffic lane due to soil tillage and sugarcane mechanical harvesting operations

Mechanical sugarcane harvesting increases soil compaction due to the intense traffic of agricultural machinery, reducing longevity of sugarcane crops. In order to mitigate the harmful effects caused by agricultural traffic on the soil structure in sugarcane fields, this study evaluated impacts of mechanical sugarcane harvesting on traffic lane under two soil tillage systems based on load bearing capacity models. The experiment was carried out in the region of Piracicaba, state of São Paulo, Brazil, on a Rhodic Nitisol, under conventional tillage (CT) and deep strip-tillage (DST). For CT soil tillage was applied to the entire area with a heavy disk harrow, at operating depths from 0.20 to 0.30 m followed by a leveling harrow at a depth of 0.15 m. For DST, soil tillage was performed in part of the area at a depth of 0.80 m, forming strip beds for sugarcane planting, while the traffic lanes were not disturbed. Undisturbed soil samples from traffic lanes were used in the uniaxial compression test to quantify preconsolidation pressure and to model the soil load bearing capacity. The surface layer (0.00-0.10 m) was most susceptible to compaction, regardless of the tillage system (CT or DST) used. In the DST, the traffic lane maintained the previous soil stress history and presented higher load bearing capacity (LBC) than the traffic lane in the CT. As in CT the soil was tilled, the stress history was discontinued. This larger LBC in DTS minimized the impacts of the sugarcane harvest. Under CT, additional soil compaction due to mechanical sugarcane harvesting in the traffic lane was observed after the second sugarcane harvest. There was a reduction in load bearing capacity from 165 kPa to 68 kPa under CT and from 230 kPa to 108 kPa under DST, from the first to the second harvest at surface layer. Water content at mechanical harvesting was the most relevant factor to maximize impacts on the soil structure in traffic lanes, for both tillage systems.

Soil compaction on traffic lane due to soil tillage and sugarcane mechanical harvesting operations

Mechanical sugarcane harvesting increases soil compaction due to the intense traffic of agricultural machinery, reducing longevity of sugarcane crops. In order to mitigate the harmful effects caused by agricultural traffic on the soil structure in sugarcane fields, this study evaluated impacts of mechanical sugarcane harvesting on traffic lane under two soil tillage systems based on load bearing capacity models. The experiment was carried out in the region of Piracicaba, state of São Paulo, Brazil, on a Rhodic Nitisol, under conventional tillage (CT) and deep strip-tillage (DST). For CT soil tillage was applied to the entire area with a heavy disk harrow, at operating depths from 0.20 to 0.30 m followed by a leveling harrow at a depth of 0.15 m. For DST, soil tillage was performed in part of the area at a depth of 0.80 m, forming strip beds for sugarcane planting, while the traffic lanes were not disturbed. Undisturbed soil samples from traffic lanes were used in the uniaxial compression test to quantify preconsolidation pressure and to model the soil load bearing capacity. The surface layer (0.00-0.10 m) was most susceptible to compaction, regardless of the tillage system (CT or DST) used. In the DST, the traffic lane maintained the previous soil stress history and presented higher load bearing capacity (LBC) than the traffic lane in the CT. As in CT the soil was tilled, the stress history was discontinued. This larger LBC in DTS minimized the impacts of the sugarcane harvest. Under CT, additional soil compaction due to mechanical sugarcane harvesting in the traffic lane was observed after the second sugarcane harvest. There was a reduction in load bearing capacity from 165 kPa to 68 kPa under CT and from 230 kPa to 108 kPa under DST, from the first to the second harvest at surface layer. Water content at mechanical harvesting was the most relevant factor to maximize impacts on the soil structure in traffic lanes, for both tillage systems.(AU)

Alternative vibro-dynamic compression processing of wood-cement composites using Amazonian wood

Wood-cement composite (WCC) is a potential construction material for tropical regions, due to its physico-mechanical properties and resistance to decay and fungi attack. However it is important to test alternative production methods and wood materials that are easier and cheaper than those traditionally used, in order to create a higher demand for this product. The aim of this work was to evaluate the use of wood from four Amazonian species (Eschweilera coriaceae, Swartzia recurva, Manilkara amazonica and Pouteria guianensis) in the production of wood-cement composites through a vibro-dynamic compression process, an alternative method to the use of a hydraulic press. The inhibition degree caused by the wood to the cement cure, measured by the factor CA, indicated that all species were compatible with Portland cement (CP II-Z). WCC with densities higher than 1,100 kg m-3 (produced with E. coriaceae and S. recurva particles) showed compressive strength values higher than 10 MPa, which fulfills the minimum requirement for lightweitgh reinforced concrete blocks for structural use. (AU)

Compósito madeira-cimento é um potencial material de construção para regiões tropicais, devido a suas propriedades físico-mecânicas e resistência ao ataque de fungos e podridão. Contudo, é importante testar métodos alternativos de produção e madeiras que sejam mais simples e baratos do que os tradicionalmente usados, para que se alcance uma maior demanda para esse produto. O objetivo deste estudo foi avaliar o uso de madeira de quatro espécies amazônicas (Eschweilera coriaceae, Swartzia recurva, Manilkara amazonica e Pouteria guianensis) na produção de compósitos de madeira-cimento (WCC) pelo processo de compactação vibro-dinâmica, um método alternativo que dispensa o uso de prensas hidráulicas. O grau de inibição à pega do cimento causado pela presença da madeira foi medido pelo fator CA e indicou que todas as quatro espécies foram compatíveis com o cimento Portland (CP II-Z). Compósitos com massa específica superior a 1.100 kg m-3 (produzidas com partículas de E. coriaceae e S. recurva) apresentaram valores de compressão axial acima de 10 MPa, requisito mínimo para classificar como blocos de concreto reforçados leves de uso estrutural.(AU)

Compressibility and water availability in Albaqualf soils under different deployment times in no-tillage

The southern Brazilian lowlands have been historically used for flooded rice cultivation. Over time, heavy machinery and intensive tillage practices have resulted in soil structure disruption, soil compaction, higher production costs and lower agricultural profitability. This study aimed to evaluate the effect of different deployment times of no-tillage (NT). Soil properties including bulk density (BD), compression index (CI), preconsolidation pressure (σp), bulk density at preconsolidation pressure (BDσp), degree of compactness (DC), soil water retention curve (SWRC), plant available water (PAW) and total organic carbon (TOC) content were evaluated using a 30-yr non-cultivated field (NC), adjacent to the experimental plots as a control. The BD, σp, BDσp and DC decreased in response to NT adoption time while the soil water holding capacity increased, allowing for higher PAW. Results from this study demonstrated the positive effects of NT on the overall quality of soils.

Compressibility and water availability in Albaqualf soils under different deployment times in no-tillage

The southern Brazilian lowlands have been historically used for flooded rice cultivation. Over time, heavy machinery and intensive tillage practices have resulted in soil structure disruption, soil compaction, higher production costs and lower agricultural profitability. This study aimed to evaluate the effect of different deployment times of no-tillage (NT). Soil properties including bulk density (BD), compression index (CI), preconsolidation pressure (σp), bulk density at preconsolidation pressure (BDσp), degree of compactness (DC), soil water retention curve (SWRC), plant available water (PAW) and total organic carbon (TOC) content were evaluated using a 30-yr non-cultivated field (NC), adjacent to the experimental plots as a control. The BD, σp, BDσp and DC decreased in response to NT adoption time while the soil water holding capacity increased, allowing for higher PAW. Results from this study demonstrated the positive effects of NT on the overall quality of soils.(AU)

Fertilizer shanks to promote soil decompaction in the seeding operation / Haste sulcadora para descompactação do solo na operação de semeadura

Intensification of soil compaction process under no-tillage (NT) is motivating the search for alternatives to mitigate soil compaction state. This study evaluated changes in soil physical and hydraulic properties caused by seeder with fertilizer shanks at different depths compared with the double discs lagged seeder, to investigate the possibility of soil decompaction by sowing under NT in southern Brazil. The study was conducted in a clayed Oxisol, for 27 years under NT. Treatments were three planting mechanisms: S0.10m: cutting disc combined with shank acting to 0.10m depth; S0.15m: cutting disc combined with shank acting to 0.15m depth and, D0.07m: double discs lagged acting to 0.07m depth in an experimental randomized block design with four replications. We evaluated the soil mechanical resistance, water infiltration rate, soil bulk density, pore size distribution and unsaturated hydraulic conductivity. Results indicated that the use of seeder with fertilizer shanks acting at 0.15m deep promoted the soil decompaction by the reduction of penetration resistance and increase of porosity and unsaturated hydraulic conductivity. To have significant increase in water infiltration rate the fertilizer shanks of the seeder must be deepened to the lower limit of the compacted surface layer.

A intensificação do processo de compactação do solo em sistema plantio direto (SPD) motiva a procura por alternativas para atenuação do estado de compactação do solo. Esse trabalho objetiva avaliar modificações em propriedades físico-hídricas do solo originadas por semeadoras equipadas com hastes sulcadoras que atuam em diferentes profundidades, em comparação à semeadora com discos duplos defasados, para investigar a possibilidade de descompactação do solo na operação de semeadura em áreas sob SPD na região Sul do Brasil. O estudo foi realizado em Latossolo Vermelho Distrófico típico, de textura argilosa, há 27 anos sob SPD. Os tratamentos foram três mecanismos de semeadura: H0,10m: disco de corte combinado com haste sulcadora atuando a 0,10m de profundidade; H0,15m: disco de corte combinado com haste sulcadora atuando a 0,15m de profundidade; e D0,07m: discos duplos defasados atuando a 0,07m de profundidade, em delineamento experimental blocos ao acaso com quatro repetições. Avaliou-se a resistência mecânica à penetração, taxa de infiltração de água no solo, densidade do solo, distribuição do tamanho de poros e condutividade hidráulica do solo não saturado. Os resultados indicaram que a utilização de semeadora com haste sulcadora atuando a 0,15m promove a descompactação do solo através da redução da resistência mecânica do solo à penetração, aumento da porosidade e da condutividade hidráulica. Para que haja aumento significativo da infiltração de água no solo, a haste sulcadora da semeadora deve ser aprofundada até o limite inferior da camada superficial compactada.

Fertilizer shanks to promote soil decompaction in the seeding operation / Haste sulcadora para descompactação do solo na operação de semeadura

Intensification of soil compaction process under no-tillage (NT) is motivating the search for alternatives to mitigate soil compaction state. This study evaluated changes in soil physical and hydraulic properties caused by seeder with fertilizer shanks at different depths compared with the double discs lagged seeder, to investigate the possibility of soil decompaction by sowing under NT in southern Brazil. The study was conducted in a clayed Oxisol, for 27 years under NT. Treatments were three planting mechanisms: S0.10m: cutting disc combined with shank acting to 0.10m depth; S0.15m: cutting disc combined with shank acting to 0.15m depth and, D0.07m: double discs lagged acting to 0.07m depth in an experimental randomized block design with four replications. We evaluated the soil mechanical resistance, water infiltration rate, soil bulk density, pore size distribution and unsaturated hydraulic conductivity. Results indicated that the use of seeder with fertilizer shanks acting at 0.15m deep promoted the soil decompaction by the reduction of penetration resistance and increase of porosity and unsaturated hydraulic conductivity. To have significant increase in water infiltration rate the fertilizer shanks of the seeder must be deepened to the lower limit of the compacted surface layer. (AU)

A intensificação do processo de compactação do solo em sistema plantio direto (SPD) motiva a procura por alternativas para atenuação do estado de compactação do solo. Esse trabalho objetiva avaliar modificações em propriedades físico-hídricas do solo originadas por semeadoras equipadas com hastes sulcadoras que atuam em diferentes profundidades, em comparação à semeadora com discos duplos defasados, para investigar a possibilidade de descompactação do solo na operação de semeadura em áreas sob SPD na região Sul do Brasil. O estudo foi realizado em Latossolo Vermelho Distrófico típico, de textura argilosa, há 27 anos sob SPD. Os tratamentos foram três mecanismos de semeadura: H0,10m: disco de corte combinado com haste sulcadora atuando a 0,10m de profundidade; H0,15m: disco de corte combinado com haste sulcadora atuando a 0,15m de profundidade; e D0,07m: discos duplos defasados atuando a 0,07m de profundidade, em delineamento experimental blocos ao acaso com quatro repetições. Avaliou-se a resistência mecânica à penetração, taxa de infiltração de água no solo, densidade do solo, distribuição do tamanho de poros e condutividade hidráulica do solo não saturado. Os resultados indicaram que a utilização de semeadora com haste sulcadora atuando a 0,15m promove a descompactação do solo através da redução da resistência mecânica do solo à penetração, aumento da porosidade e da condutividade hidráulica. Para que haja aumento significativo da infiltração de água no solo, a haste sulcadora da semeadora deve ser aprofundada até o limite inferior da camada superficial compactada. (AU)

Root system and resistance to penetration of Mombaça grass fertilized with nitrogen and irrigated / Sistema radicular e resistência a penetração de capim Mombaça fertilizado com nitrogênio e irrigado

High stocking rates in intensive pasture-based animal production systems may compromise the development of the forage roots due to increased resistance in the surface layer. This study tested the hypothesis that an increase in stocking rate resulting from different levels of nitrogen fertilization in irrigated Mombaça grass (Panicum maximum Jacq. cv. Mombaça) pasture under intermittent grazing could increase resistance to penetration and consequently the growth of the root system. A split-plot design with randomized blocks and subplots was used, including three replications and the following four treatments: 0, 200, 400 and 800 kg N ha?1 year. Evaluations performed in spring, summer and fall seasons were assigned as subplots. The highest values for area, diameter, length and percentage of root biomass (91.4%) were concentrated at the 0-10 cm soil depth, which is explained by the lower penetration resistance in this layer. Increased stocking rate resulting from increased levels of nitrogen in the Mombaça grass sward does not directly affect the penetration resistance of the soil or root characteristics. However, in the rainy season, higher nitrogen levels lead to increased resistance, as they provide higher cumulative stocking rates in this period.

Elevadas taxas de lotação em sistemas intensivos de produção animal a pasto podem comprometer o desenvolvimento das raízes de forrageiras, devido ao aumento da resistência do solo na camada superficial. Neste estudo testou-se a hipótese que o aumento da lotação animal devido a diferentes doses de nitrogênio em pasto de capim-Mombaça (Panicum maximum Jacq. cv Mombaça), irrigado e sob pastejo intermitente poderiam comprometer a resistência à penetração e consequentemente o crescimento do sistema radicular. Utilizou-se delineamento experimental em blocos ao acaso com parcelas subdivididas, com três repetições e quatro tratamentos: 0, 200, 400 e 800 kg de N ha?1 ano. Nas subparcelas foram consideradas as quatro estações do ano. As características geométricas (área, diâmetro e comprimento), e a maior porcentagem de biomassa radicular (91,4%) concentraram-se na camada de 0-10 cm de profundidade, devido a menor resistência à penetração nesta camada. O aumento da taxa de lotação decorrente do aumento das doses de nitrogênio em pastagem de capim-Mombaça não afeta diretamente a resistência à penetração do solo e as características do sistema radicular. Entretanto, o aumento das doses de nitrogênio no período das águas aumenta a resistência à penetração, proporcionando maiores taxas de lotação acumulada nestes períodos.

Root system and resistance to penetration of Mombaça grass fertilized with nitrogen and irrigated / Sistema radicular e resistência a penetração de capim Mombaça fertilizado com nitrogênio e irrigado

High stocking rates in intensive pasture-based animal production systems may compromise the development of the forage roots due to increased resistance in the surface layer. This study tested the hypothesis that an increase in stocking rate resulting from different levels of nitrogen fertilization in irrigated Mombaça grass (Panicum maximum Jacq. cv. Mombaça) pasture under intermittent grazing could increase resistance to penetration and consequently the growth of the root system. A split-plot design with randomized blocks and subplots was used, including three replications and the following four treatments: 0, 200, 400 and 800 kg N ha?1 year. Evaluations performed in spring, summer and fall seasons were assigned as subplots. The highest values for area, diameter, length and percentage of root biomass (91.4%) were concentrated at the 0-10 cm soil depth, which is explained by the lower penetration resistance in this layer. Increased stocking rate resulting from increased levels of nitrogen in the Mombaça grass sward does not directly affect the penetration resistance of the soil or root characteristics. However, in the rainy season, higher nitrogen levels lead to increased resistance, as they provide higher cumulative stocking rates in this period.(AU)

Elevadas taxas de lotação em sistemas intensivos de produção animal a pasto podem comprometer o desenvolvimento das raízes de forrageiras, devido ao aumento da resistência do solo na camada superficial. Neste estudo testou-se a hipótese que o aumento da lotação animal devido a diferentes doses de nitrogênio em pasto de capim-Mombaça (Panicum maximum Jacq. cv Mombaça), irrigado e sob pastejo intermitente poderiam comprometer a resistência à penetração e consequentemente o crescimento do sistema radicular. Utilizou-se delineamento experimental em blocos ao acaso com parcelas subdivididas, com três repetições e quatro tratamentos: 0, 200, 400 e 800 kg de N ha?1 ano. Nas subparcelas foram consideradas as quatro estações do ano. As características geométricas (área, diâmetro e comprimento), e a maior porcentagem de biomassa radicular (91,4%) concentraram-se na camada de 0-10 cm de profundidade, devido a menor resistência à penetração nesta camada. O aumento da taxa de lotação decorrente do aumento das doses de nitrogênio em pastagem de capim-Mombaça não afeta diretamente a resistência à penetração do solo e as características do sistema radicular. Entretanto, o aumento das doses de nitrogênio no período das águas aumenta a resistência à penetração, proporcionando maiores taxas de lotação acumulada nestes períodos.(AU)

Compactação de íleo por casca de arroz em neonato equino / Ileal impaction caused by rice hull in equine neonate / Compactación de íleo por cáscara de arroz en neonato equino

A compactação de íleo tem como principal etiologia a ingestão de alimentos grosseiros, com um alto teor de fibra, mas podem ocorrer em casos de infestação parasitária intensa; porém, a obstrução do íleo é considerada uma afecção rara em potros neonatais. O objetivo deste trabalho é relatar um caso de compactação de íleo causado pela ingestão acidental de casca de arroz, que acabou associada a um quadro agudo de síndrome cólica, em uma potra neonato com 4 dias de nascida da raça Quarto de Milha. O diagnóstico definitivo foi realizado através das alterações macroscópicas observadas durante a necrópsia. Apesar de não ser uma afecção comum, a compactação de íleo por ingestão de casca de arroz deve ser levada em consideração, principalmente em animais neonatos submetidos ao manejo de baia após o nascimento, visto que não é responsiva aos tratamentos convencionais dependendo da quantidade ingerida, sendo recomendado o encaminhamento cirúrgico.

The ileal impaction has as main etiology the ingestion of coarse foods, with a high fiber content but may occur in cases of intense parasitic infestation; however, an obstruction of the ileum is considered a rare condition in neonatal foals. The objective of this study is to report a case of ileal impaction caused by the accidental ingestion of rice hulls, which ended up associated with an acute colic syndrome, in a quarter horse, newborn filly with 4 days of birth. The definitive diagnosis was made through the macroscopic changes observed during the necropsy. Although it is not a common condition, ileal impaction by ingestion of rice hulls should be considered critical, especially in neonates submitted to stall management after birth, since it is not responsive to conventional treatments depending on the amount ingested, surgical referral is recommended.

La compactación de íleo tiene como principal etiología la ingestión de alimentos groseros, con un alto contenido de fibra, pero pueden ocurrir en casos de infestación parasitaria intensa. Sin embargo, la obstrucción del íleo es considerada una afección rara en potros neonatales. El objetivo de este trabajo es relatar un caso de compactación de íleo causado por la ingestión accidental de cáscara de arroz, que acabó asociada a un cuadro agudo de síndrome cólico, en una potra neonato, con 4 días de nacimiento, de la raza Cuarto de Milla. El diagnóstico definitivo se realizó a través de los cambios macroscópicos observados durante la necropsia. A pesar de no ser una afección común, la compactación de íleo por ingestión de cáscara de arroz debe ser tenida en cuenta, principalmente en animales neonatos sometidos al manejo de la bahía después del nacimiento, ya que no es responsiva a los tratamientos de acuerdo con la cantidad ingerida, siendo recomendado el encaminamiento quirúrgico.

Compactação de íleo por casca de arroz em neonato equino / Ileal impaction caused by rice hull in equine neonate / Compactación de íleo por cáscara de arroz en neonato equino

A compactação de íleo tem como principal etiologia a ingestão de alimentos grosseiros, com um alto teor de fibra, mas podem ocorrer em casos de infestação parasitária intensa; porém, a obstrução do íleo é considerada uma afecção rara em potros neonatais. O objetivo deste trabalho é relatar um caso de compactação de íleo causado pela ingestão acidental de casca de arroz, que acabou associada a um quadro agudo de síndrome cólica, em uma potra neonato com 4 dias de nascida da raça Quarto de Milha. O diagnóstico definitivo foi realizado através das alterações macroscópicas observadas durante a necrópsia. Apesar de não ser uma afecção comum, a compactação de íleo por ingestão de casca de arroz deve ser levada em consideração, principalmente em animais neonatos submetidos ao manejo de baia após o nascimento, visto que não é responsiva aos tratamentos convencionais dependendo da quantidade ingerida, sendo recomendado o encaminhamento cirúrgico.(AU)

The ileal impaction has as main etiology the ingestion of coarse foods, with a high fiber content but may occur in cases of intense parasitic infestation; however, an obstruction of the ileum is considered a rare condition in neonatal foals. The objective of this study is to report a case of ileal impaction caused by the accidental ingestion of rice hulls, which ended up associated with an acute colic syndrome, in a quarter horse, newborn filly with 4 days of birth. The definitive diagnosis was made through the macroscopic changes observed during the necropsy. Although it is not a common condition, ileal impaction by ingestion of rice hulls should be considered critical, especially in neonates submitted to stall management after birth, since it is not responsive to conventional treatments depending on the amount ingested, surgical referral is recommended.(AU)

La compactación de íleo tiene como principal etiología la ingestión de alimentos groseros, con un alto contenido de fibra, pero pueden ocurrir en casos de infestación parasitaria intensa. Sin embargo, la obstrucción del íleo es considerada una afección rara en potros neonatales. El objetivo de este trabajo es relatar un caso de compactación de íleo causado por la ingestión accidental de cáscara de arroz, que acabó asociada a un cuadro agudo de síndrome cólico, en una potra neonato, con 4 días de nacimiento, de la raza Cuarto de Milla. El diagnóstico definitivo se realizó a través de los cambios macroscópicos observados durante la necropsia. A pesar de no ser una afección común, la compactación de íleo por ingestión de cáscara de arroz debe ser tenida en cuenta, principalmente en animales neonatos sometidos al manejo de la bahía después del nacimiento, ya que no es responsiva a los tratamientos de acuerdo con la cantidad ingerida, siendo recomendado el encaminamiento quirúrgico.(AU)

Morfohistología testicular de Ceratophrys ornata (Bell) (Amphibia, Anura, Ceratophryidae) / Testicular morphohistology of Ceratophrys ornata (Bell) (Amphibia, Anura, Ceratophryidae)

En el presente trabajo se describen las características morfohistológicas del testículo de individuos adultos (n=5) de Ceratophrys ornata (Bell, 1843) provenientes de humedales del centro de Argentina. Los mismos se procesaron mediante técnicas histológicas de rutina, se cortaron a 8 µm y las láminas obtenidas se tiñeron con hematoxilina-eosina y tricrómico de Masson. Las gónadas son órganos pares, amarillentos, alargados y contorneados de 18,58 ± 0,23 mm de largo por 1,51 ± 0,13 mm de ancho. Histológicamente se observa una delgada túnica albugínea (6,29 ± 0,83 µm) rodeando a los testículos. En su interior se hallan lóculos seminíferos que miden 240,64 ± 38,52 µm de diámetro, en ellos se distinguen cistos con células espermatogénicas en distintas etapas de desarrollo. El tejido intersticial es escaso y en él se destacan las células de Leydig y vasos sanguíneos. Las espermatogonias I son las células más grandes de la serie germinal (20,03 ± 2,27 µm); poseen la cromatina granular y de aspecto multilobular, hallándose comúnmente una por cisto, estas originan a las espermatogonias II, más pequeñas (12,06 ± 1,14 µm). Los espermatocitos I presentan la cromatina levemente condensada y son un poco más chicos que sus precedentes (11,64 ± 0,36 µm). Los espermatocitos II miden 8,85 ± 0,54 µm. Las espermátidas I son esféricas, miden 5,95 ± 0,42 µm y se agrupan en cistos redondeados. Las espermátidas II, en cambio son alargadas y no se hallan dentro de cistos, pero siguen organizadas en paquetes asociadas a células de Sertoli. Los espermatozoides son células libres hacia el centro del lóculo, alargadas, flageladas y con una notable compactación nuclear. La morfohistología de los testículos analizados muestran características macroscópicas e histológicas similares a las observadas en otras especies de anfibios anuros neotropicales, presentando todas las células del linaje espermatogénico en un mismo lóculo, lo que indicaría que presentan ciclos espermatogénicos continuos.(AU)

This paper describes the morphohistological features of the testes of adult Ceratophrys ornata (Bell, 1843) (n = 5) from a wetland agroecosystem of central Argentina. The testes were processed by routine histological techniques, sectioned at 8 µm. The sheets obtained were stained with hematoxylin-eosin and Masson trichrome. The gonads are paired, yellowish, elongated contoured organs, 18.58 ± 0.23 mm long and 1.51 ± 0.13 mm wide. Histologically, there is a thin tunica albuginea (6.29 ± 0.83 µm) surrounding the testes. Inside them, there are seminiferous locules measuring 240.64 ± 38.52 µm in diameter, distinguished in cysts with spermatogenic cells at different stages of development. The interstitial tissue is scarce and the Leydig cells and blood vessels stand out. Spermatogonia I are the largest cells of the germinal series (20.03 ± 2.27 µm), have granular chromatin and multilobular aspect, commonly found in each cyst, and they originate spermatogonia II, which are smaller (12.06 ± 1.14 µm). Spermatocytes I have slightly condensed chromatin and are also slightly smaller than its predecessors (11.64 ± 0.36 µm). Spermatocytes II measure 8.85 ± 0.54 µm. Spermatids I are spherical, measuring 5.95 ± 0.42 µm and are grouped in rounded cysts. In contrast, the spermatids II are elongate and not within the cysts, but they are organized in packets associated with Sertoli cells. Sperms are free, elongated cells oriented towards the center of the loculus, flagellated, and with a remarkable nuclear compaction. The morphohistology of testes analyzed shows macroscopic and histologic features similar to those observed in other species of neotropical anuran amphibians, presenting all espermatogenic lineage cells in a single, indicating that they have continuous spermatogenic cycles.(AU)

Morfohistología testicular de Ceratophrys ornata (Bell) (Amphibia, Anura, Ceratophryidae) / Testicular morphohistology of Ceratophrys ornata (Bell) (Amphibia, Anura, Ceratophryidae)

En el presente trabajo se describen las características morfohistológicas del testículo de individuos adultos (n=5) de Ceratophrys ornata (Bell, 1843) provenientes de humedales del centro de Argentina. Los mismos se procesaron mediante técnicas histológicas de rutina, se cortaron a 8 µm y las láminas obtenidas se tiñeron con hematoxilina-eosina y tricrómico de Masson. Las gónadas son órganos pares, amarillentos, alargados y contorneados de 18,58 ± 0,23 mm de largo por 1,51 ± 0,13 mm de ancho. Histológicamente se observa una delgada túnica albugínea (6,29 ± 0,83 µm) rodeando a los testículos. En su interior se hallan lóculos seminíferos que miden 240,64 ± 38,52 µm de diámetro, en ellos se distinguen cistos con células espermatogénicas en distintas etapas de desarrollo. El tejido intersticial es escaso y en él se destacan las células de Leydig y vasos sanguíneos. Las espermatogonias I son las células más grandes de la serie germinal (20,03 ± 2,27 µm); poseen la cromatina granular y de aspecto multilobular, hallándose comúnmente una por cisto, estas originan a las espermatogonias II, más pequeñas (12,06 ± 1,14 µm). Los espermatocitos I presentan la cromatina levemente condensada y son un poco más chicos que sus precedentes (11,64 ± 0,36 µm). Los espermatocitos II miden 8,85 ± 0,54 µm. Las espermátidas I son esféricas, miden 5,95 ± 0,42 µm y se agrupan en cistos redondeados. Las espermátidas II, en cambio son alargadas y no se hallan dentro de cistos, pero siguen organizadas en paquetes asociadas a células de Sertoli. Los espermatozoides son células libres hacia el centro del lóculo, alargadas, flageladas y con una notable compactación nuclear. La morfohistología de los testículos analizados muestran características macroscópicas e histológicas similares a las observadas en otras especies de anfibios anuros neotropicales, presentando todas las células del linaje espermatogénico en un mismo lóculo, lo que indicaría que presentan ciclos espermatogénicos continuos.

This paper describes the morphohistological features of the testes of adult Ceratophrys ornata (Bell, 1843) (n = 5) from a wetland agroecosystem of central Argentina. The testes were processed by routine histological techniques, sectioned at 8 µm. The sheets obtained were stained with hematoxylin-eosin and Masson trichrome. The gonads are paired, yellowish, elongated contoured organs, 18.58 ± 0.23 mm long and 1.51 ± 0.13 mm wide. Histologically, there is a thin tunica albuginea (6.29 ± 0.83 µm) surrounding the testes. Inside them, there are seminiferous locules measuring 240.64 ± 38.52 µm in diameter, distinguished in cysts with spermatogenic cells at different stages of development. The interstitial tissue is scarce and the Leydig cells and blood vessels stand out. Spermatogonia I are the largest cells of the germinal series (20.03 ± 2.27 µm), have granular chromatin and multilobular aspect, commonly found in each cyst, and they originate spermatogonia II, which are smaller (12.06 ± 1.14 µm). Spermatocytes I have slightly condensed chromatin and are also slightly smaller than its predecessors (11.64 ± 0.36 µm). Spermatocytes II measure 8.85 ± 0.54 µm. Spermatids I are spherical, measuring 5.95 ± 0.42 µm and are grouped in rounded cysts. In contrast, the spermatids II are elongate and not within the cysts, but they are organized in packets associated with Sertoli cells. Sperms are free, elongated cells oriented towards the center of the loculus, flagellated, and with a remarkable nuclear compaction. The morphohistology of testes analyzed shows macroscopic and histologic features similar to those observed in other species of neotropical anuran amphibians, presenting all espermatogenic lineage cells in a single, indicating that they have continuous spermatogenic cycles.

Selecting the most adequate bedding material for broiler production in Brazil

Broiler chicken production is widely dispersed across the globe, and one important issue for growers is the selection of adequate bedding material, as the availability and price of substrates varies among countries and regions within a same country. This study aimed at applying a multiple criteria analysis approach for the selection of the most appropriate bedding material for broiler production. Based on field research data and growers' experience, the most desirable characteristics of a litter material were chosen as the main criteria. The selected materials were wood shavings, rice husks, chopped Napier grass (Pennisetum pupureum), 50% sugar cane bagasse (Saccharum L.) plus 50% wood shavings, 50% sugar cane bagasse (Saccharum L.) plus 50% rice husks, and pure sugar cane bagasse (Saccharum L.). The analytical hierarchy process (AHP) was applied for selecting the most suitable bedding material. Validation was performed using data from previous studies carried out in central-western Brazil on the effects of different types of bedding material on broiler carcass quality. Considering the selected criteria, several bedding materials were tested and ranked, and the results showed that wood-shavings litter was the best option (weight = 0.28), followed by rice husks (weight = 0.24). All other tested alternatives presented lower scores and were, therefore, not considered for use. The AHP approach was found to be an efficient tool to select the most appropriate litter material under specific scenarios.(AU)

Broiler litter reutilization applying different composting concepts

Broiler litter reutilization consists in using the same bedding material to cover the house floor for several broiler flocks. This requires the litter to be treated in order to reduce the amount of microorganisms, according to international recommendations. The aim of this study was to evaluate two methods of broiler litter fermentation based on composting concepts and their effect on litter and the air quality during fermentation in small-scale broiler houses. The experiment was carried out in the Environmental Laboratory I of the School of Agricultural Engineering of the State University of Campinas, utilizing six small-scale houses. Litter from the same grow-out (one, two or three) was distributed in two experimental houses, where it was either piled or spread. Before beginning the treatment, six litter samples were collected from each house and analyzed for total nitrogen content, humidity, pH and microbial counts. Litter humidity, gas emission (NH3 and CO2), environmental temperature, air relative humidity, and air velocity were determined during and after composting. Bacterial population, especially of Salmonella sp, was higher when the litter was piled compared with spread litter. However, fungi population showed a different pattern, decreasing after composting. Nevertheless, both treatments were not able to significantly reduce bacterial counts, specifically Salmonella sp, when the population before and after fermentation were compared(AU)

Litter materials and the incidence of carcass lesions in broilers chickens

The aim of this study was to evaluate the effects of different litter materials on litter compaction, broiler feathering and the incidence of carcass lesions. In the experiment, 3240 one-day-old Ross® chicks were selected by sex and distributed according to a completely randomized experimental design in a 2 x 6 factorial arrangement (two sex and six litter materials). The following litter materials were used: wood shavings, rice husks, chopped Napier grass, 50% sugar cane bagasse plus 50% wood shavings, 50% sugar cane bagasse plus 50% rice husks, and pure sugar cane bagasse. Litter compaction was weekly assessed using a penetrometer. On days 21, 35 and 42 of the experimental period, feathering on the back and legs was scored according to a 0 - 10 scale. On day 42, birds were slaughtered and the presence of bruises, scratches and footpad lesions was recorded. Litter material had no effect on bird feathering. Carcass lesions (scratches, bruises and footpad lesions) were influenced by the litter material evaluated. Birds reared on sugarcane bagasse and chopped Napier grass presented more scratches, bruises and footpad lesions than the others. Dermatitis was more evident in birds reared on sugarcane bagasse, chopped Napier grass and the combination of litter materials. It was found that males presented higher incidence of dermatitis and footpad lesions than females. Each litter material presented different compaction degrees, which increased along the experimental period. Sugarcane bagasse, chopped Napier grass and the combination of bedding materials presented the highest degree of compaction, compared with wood shavings and rice husks.(AU)

Efecto de los cortafuegos sobre el ensamble de hormigas (Hymenoptera, Formicidae) en una región semiárida, Argentina

En las regiones áridas y semiáridas los bordes de los caminos o cortafuegos pueden afectar variables micro-climáticas las cuales, a su vez, alteran la abundancia de las hormigas que nidifican en el suelo. Se estudió la densidad de nidos en ambientes con diferentes características edáficas (suelos sueltos y compactados), y de cobertura de vegetación (monte cerrado, pastizal y suelo desnudo). El área de estudio se encuentra en el sur del Caldenal (sudeste de La Pampa), tiene 12 ha clausuradas al pastoreo con seis unidades experimentales en cada una de las cuales se seleccionaron tres sitios con cobertura leñosa (monte), con cobertura herbácea (pastizal) y con el 80% de suelo desnudo (cortafuegos). En cada sitio se registraron la temperatura superficial, y la humedad, el pH, y el grado de compactación del suelo. La densidad de nidos se evaluó colocando tres transectas (80 m x 5 m) al azar por cada unidad experimental. La temperatura del suelo fue mayor en los cortafuegos y la compactación del suelo fue mayor en los ambientes de monte y pastizal. El ensamble de hormigas estudiado no mostró diferencias (p>0,05) de nidificación entre los ambientes. En cambio, Acromyrmex striatus (Roger, 1863) se encontró principalmente en los cortafuegos donde los suelos sueltos con mayor porosidad permiten mayor intercambio gaseoso e infiltración de agua. La construcción de cortafuegos favorece el establecimiento de especies cortadoras de hojas que por ventajas competitivas podrían afectar negativamente la composición de la comunidad de hormigas y las comunidades vegetales.

In arid and semiarid regions, the presence of roads or firebreaks can affect microclimatic variables that influence the abundance of soil nesting ants. We studied ant nest density in environments with different soil types (loose and compacted soil), and vegetation cover (shrubland, grassland and bare soil) south of Caldenal, La Pampa, Argentina. We selected three areas with woody cover (shrubland), herbaceous cover (grass), and 80% of bare soil (firebreaks) within a 12 ha study area where large herbivores were excluded. We recorded soil surface temperature, humidity, pH and degree of soil compaction in each area. The density of nests was assessed by randomly placing three transects (80 m x 5 m) in each experimental unit. Soil temperature was higher in firebreaks and soil compaction was higher in the shrubland and the grassland. No differences in ant assemblage were found regarding nest density among environments. However, Acromyrmex striatus (Roger, 1863) was found mostly in firebreaks where loose soil with greater porosity allows more gas exchange and water infiltration. Our findings revealed that the construction of firebreaks favors the establishment of leaf-cutting ants, which due to their competitive advantage, could negatively affect ant and plant composition in the community.

Efecto de los cortafuegos sobre el ensamble de hormigas (Hymenoptera, Formicidae) en una región semiárida, Argentina

En las regiones áridas y semiáridas los bordes de los caminos o cortafuegos pueden afectar variables micro-climáticas las cuales, a su vez, alteran la abundancia de las hormigas que nidifican en el suelo. Se estudió la densidad de nidos en ambientes con diferentes características edáficas (suelos sueltos y compactados), y de cobertura de vegetación (monte cerrado, pastizal y suelo desnudo). El área de estudio se encuentra en el sur del Caldenal (sudeste de La Pampa), tiene 12 ha clausuradas al pastoreo con seis unidades experimentales en cada una de las cuales se seleccionaron tres sitios con cobertura leñosa (monte), con cobertura herbácea (pastizal) y con el 80% de suelo desnudo (cortafuegos). En cada sitio se registraron la temperatura superficial, y la humedad, el pH, y el grado de compactación del suelo. La densidad de nidos se evaluó colocando tres transectas (80 m x 5 m) al azar por cada unidad experimental. La temperatura del suelo fue mayor en los cortafuegos y la compactación del suelo fue mayor en los ambientes de monte y pastizal. El ensamble de hormigas estudiado no mostró diferencias (p>0,05) de nidificación entre los ambientes. En cambio, Acromyrmex striatus (Roger, 1863) se encontró principalmente en los cortafuegos donde los suelos sueltos con mayor porosidad permiten mayor intercambio gaseoso e infiltración de agua. La construcción de cortafuegos favorece el establecimiento de especies cortadoras de hojas que por ventajas competitivas podrían afectar negativamente la composición de la comunidad de hormigas y las comunidades vegetales.

In arid and semiarid regions, the presence of roads or firebreaks can affect microclimatic variables that influence the abundance of soil nesting ants. We studied ant nest density in environments with different soil types (loose and compacted soil), and vegetation cover (shrubland, grassland and bare soil) south of Caldenal, La Pampa, Argentina. We selected three areas with woody cover (shrubland), herbaceous cover (grass), and 80% of bare soil (firebreaks) within a 12 ha study area where large herbivores were excluded. We recorded soil surface temperature, humidity, pH and degree of soil compaction in each area. The density of nests was assessed by randomly placing three transects (80 m x 5 m) in each experimental unit. Soil temperature was higher in firebreaks and soil compaction was higher in the shrubland and the grassland. No differences in ant assemblage were found regarding nest density among environments. However, Acromyrmex striatus (Roger, 1863) was found mostly in firebreaks where loose soil with greater porosity allows more gas exchange and water infiltration. Our findings revealed that the construction of firebreaks favors the establishment of leaf-cutting ants, which due to their competitive advantage, could negatively affect ant and plant composition in the community.

Physical quality of irrigated soil of Rio Grande do Sul State-Brazil / Qualidade física de solos irrigados do Estado do Rio Grande do Sul

Irrigated areas are characterized by an intensification of the land use, and as consequence, an intense use of the soil. This usually results in a higher pressure of the soil structure degradation, causing many times soil compaction. The objective of this study was to conduct a soil physical characterization of irrigated areas of Rio Grande do Sul State-Brazil and collect informations necessary to guide soil management decisions. The soil profile was divided in to three soil layers: superficial, intermediate and inferior. The following determinations were conducted: soil texture, bulk density (Bd), particles density and soil porosity. Soil types were grouped in ranges of clay content. For each clay content, a critical value of Bd and soil macroporosity (Macro) were established (when the result of soil was the Bd and below the macro) to classify the soil as compacted. The majority of soil samples colleted was classified in the range of 400-500 g Kg-1 of clay content in the superficial and intermediate soil layers and in the range higher than 700 g Kg-1 in the inferior soil layer. Considering the entire area sampled, 66.5% of the samples presented indication of soil compaction in the superficial layer, 20.5% in the intermediate layer and 9.5% in the inferior layer.(AU)

As áreas irrigadas caracterizam-se pela intensificação dos cultivos e, por conseqüência, por uma intensa utilização do solo. Isso resulta em uma maior pressão de degradação da estrutura do solo, ocasionando muitas vezes a compactação dos solos. O objetivo deste trabalho foi realizar a caracterização física dos solos irrigados de algumas regiões do Estado do Rio Grande do Sul, com vistas a promover uma base de informações para orientar a tomada de decisões relativas ao manejo de áreas irrigadas. Os perfis dos solos foram divididos em três camadas: (superficial, intermediária e inferior), nas quais determinaram-se a textura do solo, a densidade do solo (Ds) e de partículas e porosidade. Os solos foram agrupados em faixas de teor de argila, sendo que, para cada faixa de teor de argila, estabeleceu-se um valor crítico de densidade do solo (Ds) e de macroporosidade (Macro). As amostras com valores DS maiores que o valor cítrico e com valores de macro menores que o valor cítrico foram caracterizados com indicação de compactação. As amostras de solo coletadas foram classificadas, com maior freqüência na faixa de 400-500g kg-1 de argila, nas camadas superficial e intermediária e na faixa de argila superior a 700g kg-1 na camada inferior. Do total das áreas amostradas, 66,5% apresentaram indicação de compactação do solo na camada superficial, 20,5% na camada intermediária e 9,5% na cama(AU)