Pennisetum Clandestinum Research Articles

Diversity of Weed Species in Farms Kisii Central Sub-County, Western Kenya

This study sought to determine species diversity and Importance Values (IV) of weeds in farms in Kisii Central Sub County, Western Kenya. Eight administrative sub-locations were randomly selected. Ten farms were selected at equal distance along transect laid across each sub-location. Quadrant and a line transect laid across each farm were used to collect weed species. Five rectangular quadrants of 0.5x2m were established in each farm and individuals of each weed species identified and counted. Importance value (IV) for each weed species was computed from density, frequency and abundance. Diversity was computed by Shannon index (H’). Twenty four weed species from 22 genera in 10 families were recorded, Family Asteraceae had the highest number of species (6), followed by Solanaceae and Poaceae with 4 and 3 species respectively. The dominant weed species were Galinsoga parviflora(IV=241.6%), Pennisetum clandestinum(IV=215.8.7%),Bidens pilosa(IV=196.7%), Cynodon dactylon (IV=192.4%), Digitaria scalarum(IV=180.8%) and Cyperus esculentus(172.0%). Weed species diversity was higher (H'=2.81).

Chemical composition of two warm‐season perennial grasses subjected to proportions of defoliation

AbstractTwo experiments were conducted to assess the effect of pre‐grazing heights and proportions of defoliation on morphological and chemical composition of the grazing layer of two warm‐season perennial grasses of contrasting structures (tall tufted grass—elephant grass, Exp. I; small size stoloniferous grass—kikuyu grass, Exp. II) under intermittent stocking management. The treatments were as follows: Exp. I—factorial arrangement between two pre‐grazing heights (90 and 120 cm) and two proportions of defoliation (removal of 50% or 70% of the initial pre‐grazing heights); Exp. II—four pre‐grazing heights (10, 15, 20 and 25 cm) combined with the same proportion of defoliation (50% of the initial pre‐grazing heights). Forage samples were collected at pre‐grazing heights and clipped into the grazing layer (cutting heights defined by treatments). The following variables were analyzed: (a) forage mass; (b) proportion of leaves, stems, and dead material; (c) crude protein, neutral detergent fiber, and acid detergent fiber contents. In a general way, there were no significant differences in morphological and chemical composition of the grazing layer of treatments with proportions of defoliation of 50%. Although the treatments of 70% (Exp. I) and 10 cm (Exp. II) showed some differences, both targets impaired the grazing process and were considered as unpractical under field situations. It was concluded that forage chemical composition of warm‐season perennial grasses does not change in the upper half of the sward within a range of pre‐grazing heights, provided moderate proportions of defoliation (around 50%) are used.

Biomass Production and Potential Fixed Nitrogen Inputs from Leguminous Cover Crops in Subtropical Avocado Plantations

Nitrogen (N) fertiliser is applied to perennial horticultural crops to increase yields, but subsequent N losses in subtropical plantations may be high due to intense rainfall and warmer temperatures. While legume cover crops could potentially contribute N to the tree crops and reduce fertiliser-N requirements, few studies have quantified potential fixed-N inputs from cover crops legumes in tropical or subtropical tree crop systems. To address this, we investigated growth and N fixation of summer-growing Pinto peanut (Arachis pintoi Krapov. & W. C. Greg cv. Amarillo) and winter/spring dominant white clover (Trifolium repens L. cv. Haifa) grown as a mixed species cover crop in two commercial subtropical avocado (Persea americana Mill. cv. Hass) plantations. Legume biomass was assessed prior to mowing of the inter-row (fortnightly in summer and every 6–8 weeks over winter) and N fixation was estimated using the 15N natural abundance technique. Biomass production was 7377 kg ha−1 (930 kg ha−1 for white clover and 6447 kg ha−1 for Pinto peanut) at the first site over the 14-month period from December 2014 to January 2016, and 4467 kg ha−1 (1114 kg ha−1 for white clover and 3353 kg ha−1 for Pinto peanut) at the second site over the same period. Estimation of N fixation was not possible at the first site, due to a lack of difference in isotopic discrimination between the legume shoots and the reference plant (kikuyu (Pennisetum clandestinum Chiov.)) material. While legume shoots accumulated 157 kg N ha−1 (38 kg ha−1 for white clover and 119 kg ha−1 for Pinto peanut) across the season at site 1, the % N derived from atmosphere (%Ndfa) in legumes was relatively low (50–60% in Pinto peanut during the warmer months and around 30% in autumn and early spring, and from 13 % in April to 69% in September for white clover). The low %Ndfa in the legumes may have been due to low rainfall or molybdenum (Mo) deficiency. Ultimately the legume cover crops contributed an estimated 50 kg fixed N ha−1, which could partially offset fertiliser N requirements of the tree crop. Our results demonstrate the need to quantify N fixation in legume cover crops to assess potential N benefits as opposed to relying on typical measurements of legume biomass and N accumulation.

Comparison between a laser sensor and mechanical tools to estimate pasture mass in strata of kikuyu (Pennisetum clandestinum) pastures

Pasture meters are typically calibrated to estimate total pasture mass (TPM). Recent studies have shown that animal productivity was driven by the level of utilisation of the top leafy stratum (TLS) rather than the TPM. A study of kikuyu (Pennisetum clandestinum) pasture conducted on two farms located in southeast Queensland, Australia assessed whether pasture mass of the TLS, bottom stemmy stratum (BSS) and TPM can be more accurately estimated by using not only pasture surface height but also pasture density derived from height data captured by a laser sensor. The results indicated that there was a notable improvement of the pasture mass estimates when density was included in the calibration equations. The study also compared the accuracy of the pasture mass estimates between the laser sensor and mechanical pasture meters (rising plate meter and ruler). The results indicated that all devices provided reasonable estimates of pasture mass for TLS, BSS and total (R2 ≥ 0.75). However, pasture mass was estimated with a slightly higher level of accuracy when using the laser sensor in comparison with the other pasture meters, particularly for the top leafy stratum (R2 = 0.81 vs R2 ≤ 0.77).

Calibración del plato forrajero en praderas de kikuyo (Pennisetum Clandestinum Hochst.ex Chiov) en el trópico alto colombiano

La región andina colombiana, en el departamento de Boyacá a 2560 msnm en el cordón lechero colombiano, las explotaciones ganaderas se caracterizan por tener la especie forrajera perenne predominante conocida como Kikuyo (Pennisetum clandestinum Hochst.ex Chiov), gramínea de crecimiento estolonífero. El objetivo de este estudio, fue obtener la ecuación de regresión lineal para la adecuada calibración del plato forrajero con el fin de predecir la disponibilidad de materia seca por hectárea. Esta investigación se realizó en el trascurso del año 2014, (desde marzo hasta diciembre); para esta investigación se realizaron mediciones con un Plato Forrajero en 21 predios ganaderos pertenecientes a la región del Alto Chicamocha. Se tomaron un total de cuatrocientas (400) muestras en época seca y de lluvias. Se procedió a desarrollar la formula por medio de un método matemático de regresión lineal simple, relacionando la altura comprimida del forraje y la disponibilidad real de materia seca obtenida mediante corte y posterior secado. %. De acuerdo a la formula se determinó que por cada unidad de medida del plato forrajero, la disponibilidad de fitomasa total se incrementó en 259.42 kg de Materia Seca (MS) y se obtuvo un intercepto de 2978.92. Estos resultados conllevan al uso de la ecuación como una alternativa de cálculo de la materia seca disponible durante todo el año en praderas de Kikuyo. La ecuación resultante para la calibración del Plato Forrajero en praderas de Kikuyo (Pennisetum clandestinum) fue Kg Ms/Ha = 259.42x + 2978.9 donde se reemplazó la altura comprimida por el plato forrajero y con un coeficiente de determinación (R2) de 77.67 %.

Germination of some turfgrass species used in the green spaces in eastern Morocco

Being the main constituents of lawns, turfgrass species have been the subject of numerous studies, particularly on their behavior. But if the literature is full of tests carried out under conditions of temperate climate, the knowledge on the behavior of these species in the particular conditions of Morocco remain very limited if nonexistent. The present work is a contribution in this direction. It aims to study the behavior of turfgrass species in order to determine species resistant to edapho-climatic conditions in the eastern Morocco. Thus, a first test was conducted to determine in the laboratory under controlled thermal conditions (25 ± 1 °C) the germination rate and kinetics of five species: Pennisetum clandestinum, Lolium perenne, Festuca arundinacea, Agrostis stolonifera and Poa pratensis. The results obtained showed that the percentage and the germination speed of differ according to the species studied. In fact, Lolium perenne showed the shortest germination time with a germination rate of 92% in 7 days. Germination peaks after 9 days for the species Festuca arundinacea and Agrostis stolonifera with a percentage of 99% and 89% respectively, and at the end of the 10th day for Pennisetum clandestinum of 80%. Poa pratens is had the lowest rate, 61% after a 30 day period. The results prouve that the measured germination velocity through the germination median duration (T50) varies between one day to five days .the species Agrostis stolonifera and Lolium perenne being the fastest to germinate (1 day) and Poa pratensis is the slowest (5 days).

Feeding Protected Lysine and Methionine Modifies Milk Protein Profile in Grazing Dairy Cows

The experiment was designed to determine the effect of protected lysine (Lys) and methionine (Met) supply on milk protein profile in grazing dairy cows specifically in the caseins (CNs) and α-lactalbumin fractions. Twelve multiparous mid lactation Holstein cows producing 24 (±4.76) kg of milk were assigned to one of two treatments (six cows per treatment) during an experimental period of 21 days. In the control (C) group, cows grazed a Pennisetum clandestinum pasture and were supplemented with a commercial concentrate according to milk production. In the Met-Lys treatment, cows received the same ration supplemented with protected Lys and Met. Milk yield and composition and milk protein profile were measured at the start and the end (21st day) of the experimental period. The Tricine-SDS-PAGE and the Gel-Quant Express Analysis (Invitrogen) software were used to determine milk protein composition. Statistical analysis was performed using the SAS’s PROC MIXED procedure through a mixed model that included the animal as a random effect and the treatments as a fixed effect adjusted by covariables. Milk production averaged 23.7 (±2.0) kg cow-1 day-1 without differences between treatments (P P -1 day-1) compared to C (24.2 kg cow-1 day-1). Milk protein content (g/kg) did not differ (C = 30.4; Met-Lys = 31.1) and lactose content tended (P P β-CN also increased (P < 0.05) after protected aminoacid supply (C = 9.58; Met-Lys = 10.35). It can be concluded that milk protein composition was improved by protected Lys-Met supply without altering other compositional parameters of milk composition. Milk nutritional quality and its potential yield for cheese-making were positively enhanced.

Herbage intake by cattle in kikuyugrass pastures under intermittent stocking method

Two complementary experiments were conducted to investigate the relationships between the canopy structure of Pennisetum clandestinum (kikuyugrass) pastures created by intermittent stocking strategies and daily herbage intake by cattle. The first experiment (Exp. I) evaluated the relationship between different pre-grazing heights (10, 15, 20, and 25 cm) and a single defoliation intensity (50% reduction in the initial heights). In the second experiment (Exp. II), four defoliation intensities (40, 50, 60, or 70% reduction in height) were combined with a single pre-grazing height (25 cm). The following variables were analyzed: i) plant-part composition, herbage mass, and bulk density of the grazing layer; and ii) daily herbage intake. The data were analyzed using orthogonal polynomial contrasts. The Tukey-Kramer test was used to compare daily herbage intake means so that the differences among treatments could be characterized. In general, herbage intake decreased as the pre-grazing canopy height decreased (Exp. I; P = 0.03) and as defoliation intensity increased (Exp. II; P = 0.02). These response patterns were associated with canopy structure, both that existing before and that created during the stocking period. In conclusion, pre-grazing heights lower than 25 cm or defoliation intensities greater than 40% reduce daily herbage intake by cattle in kikuyugrass pastures under intermittent stocking.

Fotografía multiespectral para el diagnóstico fitosanitario del pasto kikuyo (Cechrus clandestinus (Hochst ex Chiov) Morrone)

Se evaluó la posibilidad de diagnosticar el estado fitosanitario del pasto kikuyo (Cechrus clandestinum (Hochst ex Chiov)), empleando un sensor multiespectral acoplado a un dron. Para esto se registraron las reflectancias de 109 puntos de muestreo en las longitudes de onda Red (R), Green (G), Blue (B), Red Edge (RE) y NIR; las cuales se relacionaron con niveles de afección por plagas determinadas bajo metodologías de campo. Las longitudes de onda R, G, B y RE se correlacionaron moderadamente con el grado de afección foliar, cuyos coheficientes fueron 0.63, 0.51, 0.51 y 0.50, respectivamente y la longitud del NIR se relacionó de manera positiva baja (r =0.14). Se evaluaron 25 modelos lineales generalizados (MLG) calculados a partir de los valores de reflectancia, donde el modelo y= (41.330* R) + (1.38*NIR), con Deviance de 0.69 se estableció como el modelo de mayor parsimonia. Además es un modelo de facil aplicación porque utiliza únicamente dos bandas.

Plant growth promoting rhizobacteria increase the efficiency of fertilisers while reducing nitrogen loss

More than half of the applied conventional fertiliser nitrogen (N) in cropping systems can be lost to the environment, resulting in water and air pollution. Farming systems that ensure efficient fertiliser use are crucial to sustain crop productivity without harming the environment. One avenue to achieve this is the use of bio-fertilisers with recognised benefits for plant nutrition and soil heath. Within this area, plant growth promoting rhizobacteria (PGPR) are increasingly applied to enhance plant nutrient acquisition and assimilation. Here, we investigated if PGPR can improve fertiliser performance. We show that the addition of PGPR to soils amended with 50% organic and 50% conventional N fertilisers increased the growth of kikuyu grass (Pennisetum clandestinum), producing yields similar to those obtained using 100% conventional N fertiliser. Encouragingly, this combination also reduced mineral N leaching by 95% relative to the all conventional fertiliser treatment. These findings suggest that using organic and synthetic fertilisers together in the presence of PGPR is a promising approach for sustaining plant growth while reducing potential pollution from inefficient use of conventional N fertilisers.

Degradabilidad ruminal del rastrojo de arroz tratado con urea en rumiantes

El rastrojo de arroz constituido por tallos y hojas, puede ser un importante subproducto de cosecha del grano de arroz para ser utilizado en la dieta de rumiantes, en razón de su abundante disponibilidad. El aumento de las regulaciones y restricciones sobre la quema de rastrojos, ha estimulado el interés por usar para otros propósitos, incluyendo la alimentación del ganado. La técnica de degradación in situ ha sido ampliamente adoptada para evaluar la tasa de degradación de alimentos en el rumen. El objetivo del trabajo fue evaluar mediante la técnica de degradación ruminal in situ, la degradabilidad de la materia seca (MS) del rastrojo de arroz tratado con seis niveles de urea: 0, 5, 10, 20, 30 y 40 g kg MS-1. Los sustratos secos fueron fragmentados en dos tamaños de partícula: una parte picada a 2 cm y otra parte molida a 2 mm, ambos tipos de sustratos fueron incubados en horno de aire forzado a 40 °C durante 10 días. Se utilizaron ocho vacas provistas de cánula ruminal para los ensayos de digestibilidad in situ, a 48 y 96 horas de incubación en rumen. Cuatro vacas recibieron una Dieta de Alta Actividad Ruminal (AAR) ajustada a consumo de 5 kg MS día-1 de heno de alfalfa (Medicago sativa L.) + heno de una mezcla forrajera (Pennisetum clandestinum Hochst. ex Chiov, Lolium perenne L. y Dactilys glomerata L.) ad libitum + 1.8 kg de concentrado, y cuatro vacas restantes recibieron una Dieta de Baja Actividad Ruminal (BAR) basada en heno de la misma mezcla forrajera y concentrado. Los datos fueron analizados mediante regresión múltiple por pasos sucesivos. Los resultados muestran aumentos en la degradabilidad de la MS con el incremento en el nivel de urea en dietas con AAR y a 96 horas de incubación. El tamaño de partícula no afectó la respuesta animal. Se concluye que este subproducto de cosecha tratado con urea puede ser una importante fuente de fibra para rumiantes en los trópicos

Development and evaluation of a constructed pilot-scale horizontal subsurface flow wetland treating piggery wastewater

Abstract This paper reports on the development and evaluation of a pilot horizontal subsurface flow constructed wetland (HSSFCW) for removal of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total nitrogen (TN) and total phosphorus (TP) from primary piggery wastewater. Two locally available plants, Pennisetum clandestinum and Pennisetum purpureum, were planted in two of three cells while the remaining unplanted cell served as the control. Monitoring of the wetland influent and effluent wastewater was carried out every two weeks for 7 months. The study revealed successful treatment of the wastewater by the wetland in terms of BOD, COD, TDS, TN and TP effluent compliance with Nigerian discharge standards. Average removal efficiencies were 66.53, 64.95, and 60.27% for BOD5; 44.85, 41.61 and 36.37% for COD; 63.61, 58.27 and 52.88% for TDS; 62.49, 58.89 and 50.14% for TN and 48.53, 44.91 and 41.27% for TP for the three wetland cells including the control respectively. Planted cells achieved the highest removal efficiency with no significant difference in pollutant removal between the two planted cells indicating their suitability for use as wetland plants. Effluent concentrations were within FEPA discharge limits except TP. The performance of the constructed wetland suggests that HSSFCW could be a suitable alternative technology for on-farm treatment of piggery wastewater in Nigeria. The study has provided a starting point for the use of HSSFCW and gives insight of the potential application of this technology for on- farm pollution control in Nigeria.

Molecular systematics of two sister clades, the Fusarium concolor and F. babinda species complexes, and the discovery of a novel microcycle macroconidium–producing species from South Africa

ABSTRACTMultilocus DNA sequence data were used to investigate species identity and diversity in two sister clades, the Fusarium concolor (FCOSC) and F. babinda species complexes. Of the 109 isolates analyzed, only 4 were received correctly identified to species and these included 1/46 F. concolor, 1/31 F. babinda, and 2/3 F. anguioides. The majority of the F. concolor and F. babinda isolates were received as F. polyphialidicum, which is a heterotypic synonym of the former species. Previously documented from South America, Africa, Europe, and Australia, our data show that F. concolor is also present in North America. The present study expands the known distribution of F. babinda in Australia to Asia, Europe, and North America. The molecular phylogenetic results support the recognition of a novel Fusarium species within the FCOSC, which is described and illustrated here as F. austroafricanum, sp. nov. It was isolated as an endophyte of kikuyu grass associated with a putative mycotoxicosis of cattle and from plant debris in soil in South Africa. Fusarium austroafricanum is most similar morphologically to F. concolor and F. babinda but differs from the latter two species in producing (i) much longer macroconidia in which the apical cell is blunt to slightly papillate and the basal cell is only slightly notched and (ii) macroconidia via microcycle conidiation on water agar. BLASTn searches of the whole genome sequence of F. austroafricanum NRRL 53441 were conducted to predict mycotoxin potential, using genes known to be essential for the synthesis of several mycotoxins and biologically active metabolites. Based on the presence of intact gene clusters that confer the ability to synthesize mycotoxins and pigments, we analyzed cracked corn kernel cultures of F. austroafricanum via liquid chromatography–mass spectrometry (LC-MS) but failed to detect these metabolites in vitro.

Accumulation of heavy metals in native Andean plants: potential tools for soil phytoremediation in Ancash (Peru).

Metal contamination is a recurring problem in Peru, caused mainly by mine tailings from a past active mining activity. The Ancash region has the largest number of environmental liabilities, which mobilizes high levels of metals and acid drainages into soils and freshwater sources, posing a standing risk on human and environmental health. Native plant species spontaneously growing on naturally acidified soils and acid mine tailings show a unique tolerance to high metal concentrations and are thus potential candidates for soil phytoremediation. However, little is known about their propagation capacity and metal accumulation under controlled conditions. In this study, we aimed at characterizing nine native plant species, previously identified as potential hyperaccumulators, from areas impacted by mine tailings in the Ancash region. Plants were grown on mine soils under greenhouse conditions during 5months, after which the concentration of Cd, Cu, Ni, Pb, and Zn was analyzed in roots, shoots, and soils. The bioaccumulation (BAF) and translocation factor (TF) were calculated to determine the amount of each metal accumulated in the roots and shoots and to identify which species could be better suited for phytoremediation purposes. Soil samples contained high Cd (6.50-49.80mg/kg), Cu (159.50-1187.00mg/kg), Ni (3.50-8.70mg/kg), Pb (1707.00-4243.00mg/kg), and Zn (909.00-7100.00mg/kg) concentrations exceeding national environmental quality standards. After exposure to mine tailings, concentrations of metals in shoots were highest in Werneria nubigena (Cd, 16.68mg/kg; Cu, 41.36mg/kg; Ni, 26.85mg/kg; Zn, 1691.03mg/kg), Pennisetum clandestinum (Pb, 236.86mg/kg), and Medicago lupulina (Zn, 1078.10mg/kg). Metal concentrations in the roots were highest in Juncus bufonius (Cd, 34.34mg/kg; Cu, 251.07mg/kg; Ni, 6.60mg/kg; Pb, 718.44mg/kg) and M. lupulina (Zn, 2415.73mg/kg). The greatest BAF was calculated for W. nubigena (Cd, 1.92; Cu, 1.20; Ni, 6.50; Zn, 3.50) and J. bufonius (Ni, 3.02; Zn, 1.30); BCF for Calamagrostis recta (Cd, 1.09; Cu, 1.80; Ni, 1.09), J. bufonius (Cd, 3.91; Cu, 1.79; Ni, 18.36), and Achyrocline alata (Ni, 137; Zn, 1.85); and TF for W. nubigena (Cd, 2.36; Cu, 1.70; Ni, 2.42; Pb, 1.17; Zn, 1.43), A. alata (Cd, 1.14; Pb, 1.94), J. bufonius (Ni, 2.72; Zn, 1.63), and P. clandestinum (Zn, 1.14). Our results suggest that these plant species have a great potential for soil phytoremediation, given their capability to accumulate and transfer metals and their tolerance to highly metal-polluted environments in the Andean region.

Nitrous oxide emission factors from cattle urine and dung, and dicyandiamide (DCD) as a mitigation strategy in subtropical pastures

The Brazilian cattle herd (>200 million) contributes, via excreta, 41% of the national emission of nitrous oxide (N2O), but little country-specific information exists on related emission factors and mitigation options. The aims of this study were: (i) to determine the N2O emission factors (EF) for dairy cattle urine and dung in a subtropical pasture and compare them with the 2% EF adopted by the IPCC; (ii) to evaluate the efficacy of the nitrification inhibitor dicyandiamide (DCD) to reduce those N2O emissions; and (iii) to determine if the best mode of DCD application is dissolved into or sprayed on urine and dung. An experiment was conducted in a kikuyu grass (Pennisetum clandestinum) pasture over a haplic Cambisol, in southern Brazil. Fresh urine and dung from Friesian dairy cows were applied with or without application of DCD; DCD was dissolved into the excreta before its application onto the soil, or was sprayed on the excreta patch. Treatments were applied four times, once per each season of 2014 (in different spots, same area). After excreta application, N2O fluxes were monitored in 10 air sampling sessions over 63–68 days, by using closed static chambers. Urine and dung were important sources of N2O, with an average EF of 0.34% for urine and 0.11% for dung; this urges the investigation of related mitigation strategies for Brazilian cattle systems. Yet, those emission factors were not as high as the IPCC default value of 2%, which suggests that this default value may need to be revised for the subtropical region. Additionally, this revision should consider the disaggregation of the EF for urine and dung. As a mitigation strategy, the use of DCD had a potential to curb N2O emission from urine patches, particularly in the cooler seasons of autumn and winter, when it reduced emissions by 60–82% after being dissolved in urine. DCD sprayed on excreta patches significantly reduced emissions in autumn only (by 47%) and thus was less efficient than when dissolved in urine. With respect to dung, there was no clear evidence that N2O emission from that excreta is mitigated by DCD, either dissolved into the dung mass or sprayed over the dung pat.––

El kikuyo, una gramínea presente en los sistemas de rumiantes en trópico alto colombiano

Los sistemas de producción de rumiantes en Colombia están soportados en el uso de forrajes, principalmente el kikuyo en el trópico alto (Cenchrusclandestinus, previamente Pennisetum clandestinum). El objetivo de este trabajo fue recopilar la información relacionada con el kikuyo e identificar nuevos campos de investigación que permitan promover un manejo eficientey sostenible de los sistemas de producción bovino soportados en praderas de kikuyo. Los trabajos sugieren que el kikuyo presenta gran resiliencia ante condiciones ambientales adversas, lo que lo perfilan como una especie de interés ante los nuevos escenarios de variabilidad climática.Además, la literatura reporta estrategias de manejo que promueven el aumento en la producción animal, el mejoramiento en la calidad final del producto y la disminución en el impacto sobre el ambiente. Sin embargo, el kikuyo presenta limitaciones en la respuesta agronómica y composicional que hace necesario desarrollar trabajos de investigación que permitan profundizar en el conocimiento de las relaciones entre las condiciones edafoclimáticas y de manejo que promueva el desarrollo de modelos de optimización de los sistemas de producción.Finalmente, se debe promover programas que permitan conocer las características fenotípicas y genotípicas del kikuyo y definir programas de mejoramiento genético que potencialicen la expresión de esta gramínea en condiciones ambientales específicas.

Uso del Kikuyo (Pennisetum Clandestinum L), residuo de la poda de áreas verdes para la obtención de ácido piroleñoso con fines agropecuarios

The large volumes of biomass generated in the maintenance of green areas are considered a focal point for the production of organic waste. In the present work, it is proposed to obtain piroleñoso acid from the precursor Pennisetum Clandestinum L (kikuyo), a very common waste product of pruning and gardening; Describes the thermochemical process for the validation of the technology for the production of the product and utilizable byproducts (coal and tar) and the evaluation of the macro elements and the structural components of the substance by means of the Fourier Transform Infrared Spectrometry (FTIR) method. (Fourier transform infrared spectroscopy), by a direct comparison, it is shown that its properties are similar to the product from Bamboo (Phyllostachys pubescense f) which has characteristics that can increase root growth in vegetables, in farm animals improves the digestibility of Nutrients and reduces harmful intestinal coliforms. The results obtained describe a yield of between 20 and 30% for the gases with a maximum delivered energy that oscillates between 150 and 1000 kcal.

In vitro rumen biohydrogenation kinetics of mixed linoleic and alfa-linolenic acids

Background: Dietary linoleic (LA) and alpha-linolenic (LN) acids are extensively isomerized and hydrogenated by rumen microbes, and this activity can further contribute to the fatty acid profile of ruminant-derived food products. Objective: To evaluate the effects of LA:LN ratio in lipid supplements on the rumen biohydrogenation kinetics of LA and LN, as well as on the trans-vaccenic acid (VA) production, using an in vitro system. Methods: Rumen fluid was collected from a fistulated steer, diluted with incubation buffer, and then incubated with 500 mg of kikuyu grass (Cenchrus clandestinus) supplemented with 16.3 mg of different LA:LN mixtures (100:0, 75:25, 50:50, 25:75 or 0:100). Incubations were performed in triplicate for a period of 0, 2, 4, 6, 8 or 16 hours. Differences between treatments were evaluated in a completely randomized design. Alternatively, computational chemistry was used to determine the changes in the Gibbs free energy (ΔGrxn) at 39 °C for the principal steps of LA and LN ruminal biohydrogenation. Results: Partial replacement of LA by LN decreased the VA concentration and its accumulation rate; it also increased the stearic acid concentration and the rates of transfer from LA to conjugated linoleic acid (CLA), and from CLA to VA. The conversion from CLAto VA(ΔGrxn = -2.65 kJ/mol) was more spontaneousthan that from trans-11, cis-15 octadecadienoic acid (TA) to VA (ΔGrxn = -0.29 kJ/mol). Conclusion: The LA:LN ratio in lipids can modulate LA and LN biohydrogenation (BH) kinetics, as well as the VA production in the rumen.

Characterisation of members of the Fusarium incarnatum-equiseti species complex from undisturbed soils in South Africa

The genus Fusarium hosts a large number of economically significant phytopathogens with a global distribution. Surprisingly, only a limited number of studies have tried to identify the natural distribution of members of this genus in undisturbed soils. Members of the Fusarium incarnatum-equiseti species complex (FIESC) are increasingly associated with plant disease, and human and animal health problems. Recently, an outbreak of kikuyu poisoning of cattle was attributed to the F. incarnatum-equiseti species complex. Thus, it is of importance to identify the natural distribution of members of the FIESC from the environment. The aim of this study was to use the phylogenetic signal within the TEF 1α gene region to characterise 54 F. incarnatum-equiseti isolates obtained from undisturbed soils from the grassland biome of South Africa. These isolates were further compared with members of the FIESC previously associated with kikuyu poisoning of cattle. The phylogenetic analysis indicated a high level of variation within this species complex. Several members were closely related to isolates implicated in the death of cattle from infected kikuyu grass.

Management characteristics of beef cattle production in Hawaii

ABSTRACT A comprehensive life cycle assessment of the US beef value chain requires the collection of region-specific data for accurate characterization of the country’s diverse production practices. Cattle production in Hawaii is very different from the rest of the country due to its unique ecosystem and geographic location. A survey of cattle producers provided information on herd size and characteristics, grazing management, forage and feed sources, and marketing. Ranch survey responses represented 44% of the state’s beef cows with operation sizes varying from 5 to 10,000 cows. Most cows (79%) were maintained on operations that finished at least some of their cattle, and the majority of those operations finished cattle on forage without concentrate feeds. Cattle were kept on natural pastures ranging in size from 16 to 52,610 ha per ranch with a stocking rate of 2.4 ha/cow on cow-calf operations and 2.0 ha/animal on operations that included older growing animals. Common forage species were Panicum maximum (guinea or green panic grass), Pennisetum clandestinum (kikuyugrass), Digitaria eriantha (pangola or digitgrass), and Trifolium repens (white clover). Reported cow and finished cattle BW were 498 ± 52 kg and 493 ± 75 kg, respectively. More ranchers marketed their beef cattle through wholesalers or distributors (34%) rather than directly to consumers (24%), retailers (20%), or other channels (17%). Marketing under grass-fed certification was reported by 39% of ranches. Information obtained is being used to define management characteristics for modeling production systems and performing a comprehensive assessment of the sustainability of beef cattle production.