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Un Modelo de Simulación de Sistemas de Engorda de Bovinos a Pastoreo
Castellaro G,Giorgio; Klee G,Germán; Chavarría R,Jorge;
Agricultura Técnica , 2007, DOI: 10.4067/S0365-28072007000200006
Abstract: a simulation model of beef cattle fattening systems based on grazing pastures was developed. the objective was to evaluate different pasture options under different management strategies, types of beef cattle, stocking densities, supplementation strategies and input prices. this model was structured based on a program, whose main module drives management input and generates result files. the dynamic section uses biological subroutines to solve equations simulating biological processes, the most important being the metabolizable energy intake and live weight change. pasture growth and nutritive value were simulated empirically from the interpolation of monthly data of pasture growth and digestibility of different pasture types. the model also calculates processes related to pasture management, forage conservation and bioeconomic aspects. the physical grazing experiment, carried out during the 1979-1980 seasons was utilized to validate the animal sub-system, a coefficient of determination higher than 95% was obtained when simulated and real values measured in the respective experiments were correlated by regression analysis, verifying the non existence of bias in the estimations. the root mean square error (rmse) was smaller than 6%, suggesting that this model is realistic and has a high degree of precision
Un Modelo de Simulación de Sistemas de Engorda de Bovinos a Pastoreo Beef Fattening Simulation Model for Different Grazing Systems
Giorgio Castellaro G,Germán Klee G,Jorge Chavarría R
Agricultura Técnica , 2007,
Abstract: Se elaboró un modelo de simulación de sistemas de producción de carne basado en utilización de pasturas, cuyo objetivo fue evaluar diferentes alternativas pratenses bajo distintas modalidades de manejo, tipos de bovinos, densidades de carga, estrategias de suplementación y precios de insumos. El modelo se estructuró sobre la base de un programa computacional, cuyo módulo principal maneja archivos de datos de manejo y genera archivos de resultados. La sección dinámica está estructurada en subrutinas orientadas a resolver ecuaciones que simulan los procesos biológicos, siendo los más importantes el consumo de energía metabolizable y el cambio de peso vivo. El crecimiento y valor nutritivo de los pastizales fue simulado empíricamente a partir de la interpolación de datos mensuales de tasas de crecimiento y digestibilidad de diferentes tipo de pasturas. El modelo también calcula los procesos relacionados con el manejo del pastoreo, conservación de forrajes y aspectos bioeconómicos. Para la validación del subsistema animal, se utilizaron los datos de peso vivo de toretes Hereford obtenidos de los experimentos físicos de pastoreo realizados durante la temporada 1979-1980. Al relacionar mediante un análisis de regresión los valores simulados con los medidos en los experimentos, se obtuvo un coeficiente de determinación superior al 95%, confirmándose la inexistencia de sesgo en la estimación. La raíz del error cuadrático medio (RMSE) no superó el 6%, lo que indicaría que este modelo es realista y tiene un alto grado de precisión. A simulation model of beef cattle fattening systems based on grazing pastures was developed. The objective was to evaluate different pasture options under different management strategies, types of beef cattle, stocking densities, supplementation strategies and input prices. This model was structured based on a program, whose main module drives management input and generates result files. The dynamic section uses biological subroutines to solve equations simulating biological processes, the most important being the metabolizable energy intake and live weight change. Pasture growth and nutritive value were simulated empirically from the interpolation of monthly data of pasture growth and digestibility of different pasture types. The model also calculates processes related to pasture management, forage conservation and bioeconomic aspects. The physical grazing experiment, carried out during the 1979-1980 seasons was utilized to validate the animal sub-system, A coefficient of determination higher than 95% was obtained when simulated and r
The Fundamental Group of Balanced Simplicial Complexes and Posets
Steven Klee
Mathematics , 2008,
Abstract: We establish an upper bound on the cardinality of a minimal generating set for the fundamental group of a large family of connected, balanced simplicial complexes and, more generally, simplicial posets.
Lower Bounds for Cubical Pseudomanifolds
Steven Klee
Mathematics , 2009,
Abstract: It is verified that the number of vertices in a $d$-dimensional cubical pseudomanifold is at least $2^{d+1}$. Using Adin's cubical $h$-vector, the generalized lower bound conjecture is established for all cubical 4-spheres, as well as for some special classes cubical spheres in higher dimensions.
SELECTIVIDAD DE OVEJAS EN LA UTILIZACIóN DE RASTROJO DE TRIGO COMO ALIMENTO
Klee G.,Germán; Pulido F.,Rubén; Chavarría R.,Jorge;
Agricultura Técnica , 2000, DOI: 10.4067/S0365-28072000000400005
Abstract: a study was carried out for 61 days in order to evaluate the selectivity of ewes grazing on wheat stubble with and without a supplement to correct nutritional deficiency. the supplement was offered at a rate of 0.45 kg per ewe per day, composed of: 46.5% oats, 6% fishmeal, 47% rape meal and 0.5 % of minerals. a field of 17.14 hectares of wheat stubble, and 120 romney marsh ewes were used. the experimental design was a randomized block, with 60 ewes per treatment. feces of six ewes per treatment, at the beginning, middle and the end of the experiment were collected in order to make a histological analysis of the relative presence (%) of vegetal species of the stubble consumed by the ewes. chemical analysis of the stubble was made in order to determine content of total protein (pt), adf , lignine, ash, n, p, k, mg, ca, mn and fe. the ewes showed a high selectivity to the species in order to balance the daily ration and great ability to encounter echium vulgare and rubus ulmifolius, species with high protein and mineral content. there was no significant difference of selectivity between treatments (p> 0.05), but there was a significant difference between periods (p<0.05). the protein content rate of vegetal species ranged between 4.3 and 22.6 % on a dry matter basis. the following percentages were found in feces: wheat stubble 29.65 % and 26.76 %; echium 23.62 % and 23.38 %; and rubus 21.55 % and 28.99% on treatments with and without supplementation, respectively
PRODUCCIóN DE CARNE BOVINA UTILIZANDO TAGASASTE (Chamaecytisus proliferus subsp. palmensis) Y PRADERAS NATURALES EN LA PROVINCIA DE ARAUCO, CHILE
Klee G.,Germán; Fraga S.,Alejandro; Canobbi V.,Juan Carlos;
Agricultura Técnica , 2001, DOI: 10.4067/S0365-28072001000200005
Abstract: the variation of the liveweight of calves grazed on tagasaste (chamaecytisus proliferus subsp. palmensis) during fall-winter was studied for the first time in chile. sixteen holstein x aberdeen angus or hereford bull calves, 7.5 months old and 197 kg liveweight, were pastured on 4.6 hectares of 3 year-old tagasaste planted on natural pasture. the following treatments were studied during fall-winter season: a) tagasaste grazing (t), and b) tagasaste grazing plus 2 kg of oats calf/day (ta). in the spring and summer, all yearling steers grazed 6 ha of natural damp pasture consisting of berry clover (trifolium fragiferum) and grass. the evaluation included availability and chemical composition of forage, variation of liveweight and carcass weight. the winter liveweight gains of the bull calves grazing on tagasaste reached 0.38 kg/bull calf/day. this value increased to 0.72 kg/ bull calf/day with the addition of oats. in the animals grazing spring and summer damp natural pasture, the daily liveweight gains were 0.9 and 1.1 kg/yearling steer for t and ta, respectively. the steers finished with 428 and 444 kg of liveweight at 17 months age and the liveweight production per ha reached 348.6 and 371.3 kg in t and ta, respectively. the carcass parameters did not differ significantly (p>0.05), however, the difference in carcass fat was significant at p<0.1, which is an important economic consideration. it is concluded that tagasaste is an acceptable resource for autumn and winter grazing.
RECRIA DE TERNEROS A BASE DE PASTOREO DE TAGASASTE (Chamaecytisus proliferus ssp. palmensis) SUPLEMENTADOS CON AVENA GRANO EN LA PROVINCIA DE ARAUCO, CHILE
Klee G.,Germán; Ovalle M.,Carlos; Canobbi V.,Juan C.;
Agricultura Técnica , 2003, DOI: 10.4067/S0365-28072003000100004
Abstract: the objective of this experiment was to evaluate the liveweight (lw) gains of calves grazing during the fall-winter season on 4 year-old tagasaste (chamaecytisus proliferus ssp.palmensis), 2.500 trees per ha, planted on natural pasture, and to evaluate the effect of two levels of oat (avena sativa l.) grain supplementation. eighteen holstein x aberdeen angus or hereford bull calves of 184 kg liveweight and 7.5 months of age were used. the treatments studied were: t1: tagasaste grazing; t2: tagasaste grazing plus 2 kg of oats calf-1 day-1; and t3: tagasaste grazing plus 4 kg of oats calf-1 day-1. the daily lw gain differed significantly (p < 0.05) and was 0.6, 1.8, and 1.10 kg calf-1 and 270, 382 and 529 kg ha-1 in the treatments t1, t2 and t3, respectively. the estimated consumption of tagasaste dm (leaves and soft stems) was 3.7 kg dm bull-calf - 1 day-1. the components of tagasaste plants were 25.3% leaves, 11.3% tender stems and 63.4% woody stems. the mean dm per bush was 1983 g plant-1 and 4,957 kg ha-1. the cp and me content in leaves were 21.8% and 2.4 mcal kg-1; in soft stems were 9% and 1.71 mcal kg-1; in ripe stems 3.4% and 1.9 mcal kg-1, respectively. tagasaste was an acceptable resource for winter grazing that on being supplemented with oat grain permitted significantly better liveweight gains.
RECRIA DE TERNEROS A BASE DE PASTOREO DE TAGASASTE (Chamaecytisus proliferus ssp. palmensis) SUPLEMENTADOS CON AVENA GRANO EN LA PROVINCIA DE ARAUCO, CHILE Calf fattening based on tagasaste (Chamaecytisus proliferus ssp. palmensis) grazing and supplemented by oats in Arauco province, Chile
Germán Klee G.,Carlos Ovalle M.,Juan C. Canobbi V.
Agricultura Técnica , 2003,
Abstract: El experimento tuvo como objetivo evaluar las variaciones de peso vivo (PV) de terneros en pastoreo oto o - invierno de tagasaste (Chamaecytisus proliferus ssp. palmensis), de cuatro a os de edad, 2.500 árboles ha-1, establecido sobre pradera natural, y evaluar el efecto de la suplementación con dos niveles de avena grano (Avena sativa L.). Se utilizaron 18 terneros Holando Europeo x Aberdeen Angus o Hereford, de 184 kg PV y 7,5 meses de edad. Los tratamientos fueron: T1: pastoreo de tagasaste; T2: T1 + 2 kg diarios de avena ternero-1; y T3: T1 + 4 kg diarios de avena ternero-1. Las ganancias diarias de PV fueron significativamente distintas (P < 0,05), y la producciones de PV (kg ha-1), fueron: 0,6; 1,8; y 1,10 kg ternero-1 , y 270; 382; y 529 kg PV ha-1 en los tratamientos T1, T2 y T3, respectivamente. El tagasaste consumible (hojas y tallos tiernos) se estimó en 3,7 kg diarios de MS por ternero. Los componentes de un arbusto correspondieron 25,3% de hojas, 11,3% de tallos tiernos, y 63,4% de tallos le osos. El promedio de MS total por arbusto alcanzo a 1.983 g, y por ha 4.957 kg . La PT y EM de las hojas fue respectivamente, 21,8% y 2,4 Mcal kg-1, en tallos tiernos 9% y 1,71 Mcal kg-1, y en tallos le osos 3,4% y 1,9 Mcal kg-1. El tagasaste fue recurso alimenticio invernal aceptable que al ser suplementado con avena grano permitió obtener ganancias de PV significativamente mejores. The objective of this experiment was to evaluate the liveweight (LW) gains of calves grazing during the fall-winter season on 4 year-old tagasaste (Chamaecytisus proliferus ssp. palmensis), 2.500 trees per ha, planted on natural pasture, and to evaluate the effect of two levels of oat (Avena sativa L.) grain supplementation. Eighteen Holstein x Aberdeen Angus or Hereford bull calves of 184 kg liveweight and 7.5 months of age were used. The treatments studied were: T1: Tagasaste grazing; T2: Tagasaste grazing plus 2 kg of oats calf-1 day-1; and T3: Tagasaste grazing plus 4 kg of oats calf-1 day-1. The daily LW gain differed significantly (P < 0.05) and was 0.6, 1.8, and 1.10 kg calf-1 and 270, 382 and 529 kg ha-1 in the treatments T1, T2 and T3, respectively. The estimated consumption of tagasaste DM (leaves and soft stems) was 3.7 kg DM bull-calf - 1 day-1. The components of tagasaste plants were 25.3% leaves, 11.3% tender stems and 63.4% woody stems. The mean DM per bush was 1983 g plant-1 and 4,957 kg ha-1. The CP and ME content in leaves were 21.8% and 2.4 Mcal kg-1; in soft stems were 9% and 1.71 Mcal kg-1; in ripe stems 3.4% and 1.9 Mcal kg-1, respectively. Tagasaste w
PRODUCCIóN DE CARNE BOVINA UTILIZANDO TAGASASTE (Chamaecytisus proliferus subsp. palmensis) Y PRADERAS NATURALES EN LA PROVINCIA DE ARAUCO, CHILE Beef production using tagasaste (Chamaecytisus proliferus subsp. palmensis) and natural pastures in Arauco province Chile
Germán Klee G.,Alejandro Fraga S.,Juan Carlos Canobbi V.
Agricultura Técnica , 2001,
Abstract: El experimento tuvo como objetivo evaluar las variaciones de peso vivo (PV) de terneros en pastoreo oto o-invierno de tagasaste (Chamaecytisus proliferus subsp. palmensis), establecido sobre pradera natural, y estudiar el efecto al suplementar estos forrajes con avena grano. Se usaron 16 terneros enteros mestizos Holandés Europeo x Aberdeen Angus o Hereford, de 7,5 meses de edad y 197 kg de PV, los que pastorearon en 4,6 ha de tagasaste de 3 a os de edad, plantados sobre pradera natural. Se estudiaron durante el invierno los tratamientos: a) Pastoreo de tagasaste (T), y b) Pastoreo de tagasaste más 2 kg diarios de avena grano/animal (TA). En primavera-verano todos los novillos pastorearon 6 ha de pradera natural de vega de trébol frutilla (Trifolium fragiferum) y gramíneas. Se evaluaron la disponibilidad y composición química del forraje, variaciones de PV y características de las canales. Los terneros que pastorearon tagasaste alcanzaron ganancias invernales diarias de 0,39 kg/animal, valor que aumentó a 0,72 kg/animal en terneros suplementados con avena. Las ganancias diarias en praderas naturales de vega fluctuaron entre 1,1 y 0,9 kg/animal para T y TA, para el ensayo de primavera-verano, respectivamente. Los animales finalizaron con 444 y 428 kg PV a los 17 meses de edad, y la producción anual de PV por hectárea alcanzó a 349 y 371 kg en los tratamientos T y TA, respectivamente. Las características de las canales no difirieron significativamente (P>0,05), sin embargo la diferencia de la grasa de cobertura fue significativa (P<0,10), aspecto importante de considerar en la evaluación económica de los tratamientos. The variation of the liveweight of calves grazed on Tagasaste (Chamaecytisus proliferus subsp. palmensis) during fall-winter was studied for the first time in Chile. Sixteen Holstein x Aberdeen Angus or Hereford bull calves, 7.5 months old and 197 kg liveweight, were pastured on 4.6 hectares of 3 year-old tagasaste planted on natural pasture. The following treatments were studied during fall-winter season: a) Tagasaste grazing (T), and b) Tagasaste grazing plus 2 kg of oats calf/day (TA). In the spring and summer, all yearling steers grazed 6 ha of natural damp pasture consisting of berry clover (Trifolium fragiferum) and grass. The evaluation included availability and chemical composition of forage, variation of liveweight and carcass weight. The winter liveweight gains of the bull calves grazing on tagasaste reached 0.38 kg/bull calf/day. This value increased to 0.72 kg/ bull calf/day with the addition of oats. In the animals grazing sprin
SELECTIVIDAD DE OVEJAS EN LA UTILIZACIóN DE RASTROJO DE TRIGO COMO ALIMENTO Selectivity of ewes grazing on wheat stubble
Germán Klee G.,Rubén Pulido F.,Jorge Chavarría R.
Agricultura Técnica , 2000,
Abstract: Se realizó un estudio durante 61 días, con el objeto de evaluar la selectividad de los ovinos cuando se utiliza rastrojo de trigo como único alimento, y cuando se mejora la ración diaria de los ovinos con un concentrado, que corrija en parte las deficiencias de la paja de trigo. El concentrado se suministró a razón de 0,45 kg oveja-1 día-1 y contenía 46,5% avena grano, 6% harina de pescado, 47% afrecho de raps y 0,5% de sales minerales. Se utilizaron 17,14 ha de rastrojo de trigo y 120 ovinos Romney Marsh. El dise o empleado fue bloques completamente al azar, con 60 animales por tratamiento. Se muestrearon fecas en seis ovejas por tratamiento al inicio, mitad y final del experimento, se sometieron a análisis histológico para determinar la presencia relativa de las especies componentes del rastrojo consumidas por los ovinos. Se efectuaron análisis químico de los componentes del rastrojo para proteína total (PT), fibra detergente ácido (FDA), lignina, cenizas, N, P, K, Mg, Ca, Mn, y Fe. Las ovejas mostraron un alta selectividad de las especies para formular su dieta diaria, y gran habilidad para consumir hierba azul y zarzamora, especies que presentan un elevado tenor proteico y mineral. La selectividad no difirió significativamente entre tratamientos (P>0,05), pero si entre períodos (P<0,05). Los rangos de contenido de proteína de las especies fluctuaron entre 4,3 y 22,6% base materia seca. Se observó en las fecas predominancia de paja de trigo 29,65% y 26,76%, seguida de hierba azul 23,62% y 23,38%, y zarzamora 21,55% y 28,99%, en los tratamientos sin suplemento y con suplementación, respectivamente A study was carried out for 61 days in order to evaluate the selectivity of ewes grazing on wheat stubble with and without a supplement to correct nutritional deficiency. The supplement was offered at a rate of 0.45 kg per ewe per day, composed of: 46.5% oats, 6% fishmeal, 47% rape meal and 0.5 % of minerals. A field of 17.14 hectares of wheat stubble, and 120 Romney Marsh ewes were used. The experimental design was a randomized block, with 60 ewes per treatment. Feces of six ewes per treatment, at the beginning, middle and the end of the experiment were collected in order to make a histological analysis of the relative presence (%) of vegetal species of the stubble consumed by the ewes. Chemical analysis of the stubble was made in order to determine content of total protein (PT), ADF , lignine, ash, N, P, K, Mg, Ca, Mn and Fe. The ewes showed a high selectivity to the species in order to balance the daily ration and great ability to encounter Echium vulgare
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