Search

Abstract Athropogenic changes have caused profound repercussions, which have led to a progressive degradation of natural resources. In the case of the Ecuadorian Amazon, the high rate of deforestation, changes in land use and extensive livestock management have led to low production rates with an eminent threat to the thermal comfort of ruminants. The present study aimed to contrasts how the use of SPs represents a viable option for the reconversion of extensive livestock farming. The current study compared the use of silvopastoral systems (SPs) versus a conventional pastoral system, as an alternative for the recovery of degraded areas. Therefore, under a completely randomized block design, Brachiaria decumbens was evaluated with three of treatments, such as Control = conventional pastoral, SPs1 = density 100 trees/ha-1 and SPs2 = 150 trees/ha-1. All environmental variables and bioclimatic indicators (temperature and radiant heat load: RHL) were shown to be mitigated under SPs (P < 0.001), which translates into better thermal comfort for ruminants (RHL; 638 vs. 1749 ± 40; P < 0.001). Although, the treatments affected all the agronomic variables of Brachiaria decumbens (P < 0.001 to 0.004), the month conditioned most of the chemical determinations (P < 0.001). This means that the use of SPs in the medium or long term could contribute to the recovery of pastures in degradation processes. Consequently, SPs as a clean production alternative would help improve aspects such as soil quality, agronomic yields, as well as greater nutritional quality of pastures. In any case, long-term studies should be performed to contrast our responses.

The study was conducted to determine the effects of supplementing probiotics and concentrates on intake and growth performance of Sahelian does fed Brachiaria decumbens grass. Twenty-four Sahelian does averaging one year and weighing 13.3 ± 1.16 kg were assigned randomly in a 2 × 2 factorial arrangement to four treatments in a Completely Randomized Design with 6 replicates and used to measure intake and live weight changes for 14 weeks. The factors were levels of concentrate and probiotics. Blood samples were taken for the determination of haematological and biochemical parameters. The results revealed differences (P

The study was conducted to determine the effects of supplementing probiotics and concentrates on intake and growth performance of Sahelian does fed Brachiaria decumbens grass. Twenty-four Sahelian does averaging one year and weighing 13.3 ± 1.16 kg were assigned randomly in a 2 x 2 factorial arrangement to four treatments in a Completely Randomized Design with 6 replicates and used to measure intake and live weight changes for 14 weeks. The factors were levels of concentrate and probiotics. Blood samples were taken for the determination of haematological and biochemical parameters. The results revealed differences (P < 0.05) in total dry matter intake, live weight changes and feed conversion ratio attributable to treatment effects. The differences observed in total dry matter intake led to improvements in average daily gain, feed conversion ratio and growth rate. All blood haematological indices with the exception of mean cell volume were impacted positively by treatment effects. White blood cell and total protein contents improved linearly with probiotics and higher level of concentrate supplementation, while total cholesterol content declined (P < 0.05). The results highlighted the positive impact of probiotics and higher level of concentrate supplementation on growth performance and blood profile of growing Sahelian does on a basal diet of Brachiaria decumbens grass. [ABSTRACT FROM AUTHOR]

The main goal of this investigation was to determine the effects of Brachiaria decumbens leaf meal on the health performance, blood biomarkers, and relative telomere length of broiler chickens raised in tropical conditions. A total of 300, day-old, male, Ross 308 broilers were divided into six groups and given various feeding regimens based on a completely randomized design model. T1 commercial feed was devoid of antibiotics (negative control) whereas T2 commercial feed was supplemented with 100 mg/kg oxytetracycline (positive control). Commercial diets supplemented with 25, 50, 75, and 100 mg/kg of powdered B. decumbens leaf meal was given to the birds in treatments T3, T4, T5, and T6, respectively. Throughout the 42-day study, there were a few occurrences of leg problems, diarrhoea, and fatalities, but no statistical association was detected. The growth performance, leucocyte profile, immunoglobulin and cytokine concentrations, and relative telomere length, however, differed substantially among treatments. T3 broilers fed with diets supplemented with 25 mg/kg of B. decumbens leaf meal exhibited the best growth performance (highest final body weight and body weight gain; lowest cumulative feed conversion ratio), leucocyte profiling (increased total white blood cell count, monocytes, and basophil count; decreased heterophil to lymphocyte ratio), immunoglobulins (up-regulated IgG, IgA, and IgM), cytokines (increased IL4 and IL7), and telomere length. In conclusion, B. decumbens leaf meal can be used instead of antibiotics to enhance the growth and health of broilers raised in hot, humid conditions. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The primary goal of this research was to elucidate the novel influence of Brachiaria decumbens supplementation on broiler chicken growth performance, nutritional digestibility, cecal microbiota, intestinal histomorphology, carcass characteristics, and meat quality. A total of 300 male day-old Ross 308 broiler chickens were randomly subjected to six different treatment groups having five replicates per treatment with 10 birds in each replicate. In treatment 1, broiler chickens were fed commercial diets with no added additives; in treatment 2, broiler chickens were offered commercial diets containing 100 mg/kg of the antibiotic oxytetracycline. However, in treatments 3, 4, 5, and 6, broiler chickens received similar commercial diets supplemented with 25 mg/kg, 50 mg/kg, 75 mg/kg, and 100 mg/kg of B. decumbens ground leaf powder, respectively, without antibiotics. Throughout the 42-day trial, the body weight gain and total feed intake for each replicate were recorded every week to determine the growth performance. Then, on 21th and 42nd day, ten broilers from each treatment (two in each replicate) were randomly selected and slaughtered to assess the digestibility of nutrients, histomorphology of the small intestine, the population of the cecal microbiota, carcass characteristics, as well as quality of both breast and drumstick muscle. There were differences (p < 0.05) in the growth performance, apparent ileal nutrient digestibility, intestinal histomorphology, carcass characteristics, and meat quality. Animals supplemented with 25 mg/kg of B. decumbens had higher growth performance and better ileal nutrient digestibility of protein, fiber, and ether extract, as well as higher villi height and carcass percentage with superior meat quality. Besides, the growth of E. faecalis during the starter phase was inhibited. In summary, B. decumbens supplementation at 25 mg/kg may be suggested as an optimal dose of as a prophylactic as well as an alternative for antibiotic growth promoter in stimulating the productivity of commercial broilers. This unconventional phytobiotic supplementation could be the key to replacing unnecessary antibiotics used in poultry feed. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Grasslands / Forrajes Tropicales is the property of International Centre for Tropical Agriculture - CIAT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El trópico húmedo ecuatoriano tiene potencial para la producción ganadera y los cultivares de Urochloa pueden ser una opción para la producción de alimento, pero se deben considerar las condiciones ambientales y de manejo, ya que estas determinarán el rendimiento y valor nutritivo del forraje. Se evaluó el rendimiento de materia seca total (MST; t ha-1), componentes morfológicos (%; hoja, tallo, material muerto e inflorescencia) y la digestibilidad in situ de la MS (DISMS; g kg-1) en cinco cultivares de Urochloa: Mulato II, Marandú, Xaraés, Piatá y Señal (testigo), a tres edades de rebrote (4, 6 y 8 semanas), durante las épocas de lluvias (ELL) y seca (ESE). Los datos se analizaron dentro de cada época con un diseño de bloques completos al azar en arreglo de parcelas divididas. Durante la ELL no hubo diferencia (P>0.05) en MST, entre cultivares evaluados. Durante la ESE Marandú presentó menor rendimiento que Xaraés (0.92 vs 1.21 t ha-1). La proporción de componentes morfológicos fue diferente entre cultivares (P

The humid tropics of Ecuador is a potential livestock production area. Urochloa spp. cultivars are a forage option in this region. Environmental and management conditions determine forage yield and nutritional value and should be researched prior to establishing new forage species. An evaluation was done of total dry matter yield (TDM; t ha-1), morphological components proportions (%; leaf, stem, dead material and inflorescence) and in situ dry matter digestibility (DMD; g kg-1)) in five Urochloa cultivars (Mulato II, Marandú, Xaraés, Piatá and Señal [control]) and at three regrowth ages (4, 6 and 8 wk) during the rainy and dry seasons. A completely randomized block design in a split plot arrangement was used to analyze the data by season. During the rainy season, TDM did not differ (P>0.05) between cultivars. In the dry season, Marandú had a lower yield than Xaraés (0.92 vs 1.21 t ha-1). Morphological component proportions differed between cultivars (P<0.05), although the leaves contributed the most overall to yield. From four to eight weeks, DMD decreased from 64 to 56 % in the rainy season and from 60 to 56 % in the dry season. The evaluated cultivars exhibited acceptable TDM yields (2.6 t ha-1 in rainy season, 1.0 t ha-1 in dry season) and DMD (602 g kg-1 in rainy season, 574 g kg-1 in dry season). They are adequate forage alternatives for livestock in the humid tropics of Ecuador. [ABSTRACT FROM AUTHOR]

A Queilite angular é caracterizada por um processo inflamatório envolvendo as comissuras labiais, tendo entre seus desencadeantes os fatores mecânicos, sendo pouco descrita em animais. O objetivo foi apresentar um caso clínico envolvendo uma ovelha atendida na Clínica Veterinária da PUCPR, campus Toledo. O animal chegou à clínica apresentando uma lesão em rima labial inferior esquerda de consistência firme e sem o acometimento de ossos ou dentes. O diagnóstico definitivo se deu por meio do histórico e exames complementares (histopatológico e cultura fúngica). O exame histopatológico da lesão revelou uma Queilite angular traumática pelo consumo recorrente de Brachiaria decumbens. Por meio do cultivo fúngico, foi possível diagnosticar o desenvolvimento secundário de uma zigomicose por Mucor racemosus. Este trabalho demonstra a importância do correto diagnóstico de enfermidades na clínica veterinária, bem como a apresentação de uma enfermidade rara ainda não relatada na espécie ovina.

This research was aimed at studying the in vitro ruminal biohydrogenation (BH) of C18 fatty acids (FA) in mixtures of Indigofera zollingeriana and Brachiaria decumbens. Four combinations of experimental rations of I. zollingeriana : B. decumbens were tested i.e., IZ 1 (45%:45%), IZ 2 (60%:30%), IZ 3 (75%:15%), and IZ 4 (90%:0%). The remaining 10% in in each ration was rice bran. The experimental design was based on a completely randomized design with five replicates. Results revealed that there was a statistically significant difference (P0.05). Composition of C18:0 after incubation showed a significant difference (P

Se planteó la hipótesis de que es posible que el inóculo de diferentes especies de rumiantes con capacidades digestivas diferentes que se alimentan de un determinado forraje puede mostrar diferentes utilizaciones de alimento en comparación con otras especies de rumiantes. Se evaluaron cinco gramíneas Brachiaria: B. decumbens cv. Basilisk, B. decumbens acceso D70, B. humidicola cv. Tupi, B. humidicola cv. Común, y B. ruziziensis acceso R124, en dos edades de rebrote (21 y 42 d). Se analizó la producción, el contenido bromatológico, la digestibilidad de materia seca in vitro (DMSiv) y la digestibilidad de la fibra detergente neutro in vitro (DFDNiv) utilizando inóculos bovinos u ovinos. El experimento utilizó un diseño factorial de 5 × 2 × 2 y encontró efectos significativos para la variedad de gramínea y la edad de rebrote. Además, se encontraron interacciones significativas de gramínea × edad en la materia seca, la proteína cruda, la fibra detergente neutro y la fibra detergente ácido de la muestra total y lamina de la hoja. Hubo un efecto significativo de la variedad de gramínea y la edad de la gramínea en la masa del forraje, la relación lámina de la hoja/tallo, lámina de la hoja, tallo, material senescente y crecimiento. En los ensayos de la digestibilidad in vitro, el origen del inóculo mostró un efecto significativo en algunas variedades. Debido a las diferencias en los ensayos in vitro, se recomendó el uso de inóculos específicos de las especies para las evaluaciones de alimentos según el animal al que se destina. Asimismo, B. decumbens cv. Basilisk presentó la mejor digestibilidad in vitro (DMSiv y DFDNiv) en inóculo bovino, mientras que B. humidicola cv. Tupi tuvo mejor digestibilidad in vitro (DMSiv y DFDNiv) en inóculo ovino.

It was hypothesized that i t is possible that inoculum from different ruminant specie s with different digesti ve abilities feeding from a certain forage may show different feed utilization s comparing to other ruminant specie s . Five Brachiaria grass es were evaluated : B . decumbens cv . Basilisk, B . decumbens access D70, B . humidicola cv . Tupi, B humidicola cv . Common, and B . ruziziensis access R124, at two regrowth ages (21 and 42 d) . Production, bromatological content, in vitro dry matter digestibility ( iv DMD ) and in vitro neutral detergent fiber digestibility ( iv NDFD ) were analyzed using bovine or ovine inoculums . The experiment use d a 5 × 2 × 2 factorial design and found significant effect s for grass variety and regrowth age . In addition, significant interaction s from grass × age on dry matter, crude protein, neutral detergent fiber and acid detergent fiber of total sample and leaf blade were found . There were significant effect of grass variety and grass age on forage mass, leaf blade / stem ratio, leaf blade, stem, senescent material and growth. I n vitro digestibility assays of inoculum source showed significant effect i n some varieties . Due to differences in in vitro assays, it was recommended t he use of specie s - specific inoculums for feed evaluations according to the animal it is intended for . Also, B. decumbens cv . Basilisk presented the best in vitro digestibility ( iv DMD and iv NDFD ) in bovine inoculum, whereas B. humidicola cv . Tupi had better in vitro digestibility ( iv DMD and iv N D FD) in ovine inoculum. [ABSTRACT FROM AUTHOR]

Abstract Water magnetization and geoprocessing are increasingly utilized tools in weed management. Our objective was to study the influence of water magnetization on herbicide efficiency and to verify whether there is a relationship between control scores and the normalized difference vegetation index (NDVI). In the laboratory experiment, water was subjected to magnetization and evaluated with respect to four characteristics. In the field experiment, plots of Brachiaria grass were subjected to treatments in a factorial scheme (6 × 2 + 1). Six herbicidal factors (doses of glyphosate and glyphosate + 2,4-D) and the magnetization or absence of magnetization of the spray solution were evaluated and compared against the control treatment (without spraying). Weed control assessments were carried out six times. Images were obtained using an embedded multispectral camera to determine the NDVI values. Data related to water characteristics were analyzed using the t test. Weed control and NDVI data were subjected to analysis of variance and are presented in regression graphs. Dispersion analysis of NDVI data was performed according to the control scores. The magnetization process decreased the pH of the water and increased the surface tension, but it did not influence the control scores or the NDVI. As the glyphosate dose was increased, the control scores were higher and the NDVI values were lower. Magnetized water did not affect the biological efficiency of the herbicides, and there was a strong correlation between the control scores and the NDVI values.

A simulated grazing was developed with Brachiaria decumbens cv. Basilisk, to study the performance of dairy cows during rainy season in two grazing intensities: T1 = 75 and T2 = 150 LAU ha-1 day-1. Twenty Siboney crossbred cows were studied, between the second and third lactation, with 480 ± 8 kg of body weight (10 animals treatment-1), grazing 15 hours a day. InfoStat statistical program, version 12.0, was used for data processing. T2 animals showed lower grass availability (P = 0.0072) and intake decrease (P = 0.0362) (24.35 vs. 17.57 and 12.77 vs. 11.33 kg DM animal-1 day-1 for availability and intake of animals of 75 and 150 LAU ha-1 day-1). No differences were reported in individual production per cow and dairy components. However, production per area increased (P = 0.0001) by 1.74 times in T2 with respect to T1 (3,279.99 and 5,722.71 kg of milk ha-1 rainy season-1, for T1 and T2, respectively). Production cost of a liter of milk increased by 11.8 % in the treatment with the lowest intensity (2.17 vs. 1.96 $ L-1, for 75 and 150 LAU ha-1 day-1). Results indicate that animals from the treatment with 150 LAU ha-1 day-1 showed no differences in individual production, although they increased productivity per grazing area by 2,842.72 L, and decreased costs by 0.21 $ produced L-1. [ABSTRACT FROM AUTHOR]

Tools that generate models with good biomass predictive capacity are essential to maintain the sustainability of production systems. The objective was to analyze the relationship between forage biomass and structural variables and generate models to predict total forage biomass (TFB) and green leaf blade biomass (GLB). Irrigated pastures of Brachiaria decumbens Stapf 'Basilisk' were kept under rotational stocking with sheep (Ovis aries L.) The TFB, GLB, leaf area index (LAI), height (cm), and normalized difference vegetation index (NDVI) were evaluated. The experimental design was completely randomized with four replicates: ten and five cycles of defoliation management, respectively, were used to generate and validate the stages of the models. The best goodness of fit was obtained by nonlinear models for both TFB and GLB, which can be confirmed by high Spearman's correlations and significance (P < 0.0001). The path analysis showed low collinearity (42.60) between NDVI, LAI, and height; the high determination coefficient (R²) with values of 0.8421 and 0.7767 demonstrated their associations with TFB and GLB, respectively. Among the studied models to predict TFB and GLB, only exponentials using NDVI and power using LAI and height showed the best fit. In the validation stage, the models related to height exhibited the highest performance with 0.9531 (TFB) and 0.9638 (GLB) d-index, -2.3 (TFB) and -7.20 (GLB) bias, and 0.8532 (TFB) and 0.8932 (GLB) R². Only nonlinear models using height (cm) to predict TFB and GLB had the best practical application potential, thus ensuring efficiency in data collection. [ABSTRACT FROM AUTHOR]

The present study aims to determine the hematology, serum biochemistry, and acute phase proteins (APPs) responses of both serum and cerebrospinal fluid (CSF) in sheep fed with low and high levels of Brachiaria decumbens (B. decumbens) diets at different time phases. A total of 30 6-month-old male Dorper cross sheep were randomly divided into three treatment groups consisted of 10 sheep each. Treatment 1 (control) sheep were fed with Pennisetum purpureum and concentrates as the basal diet, whereas Treatments 2 and 3 sheep were fed with low (10%) and high (60%) level of B. decumbens, respectively. The hematology results revealed that there were significant differences (p < 0.05) in the red blood cells, mean corpuscular volume, mean corpuscular hemoglobin concentration, white blood cells, neutrophils, monocytes, eosinophils, basophils, platelets, and plasma proteins between groups. Except for packed cell volume, there were also significant differences in all hematology parameters at different time phases. All biochemistry parameters except creatinine revealed significant differences among treatment groups. However, there were significant differences in all parameters between time. On the other hand, APPs results showed significant differences in the serum haptoglobin and serum amyloid A in both serum and CSF between groups and time. [ABSTRACT FROM AUTHOR]

Brachiaria decumbens is a highly productive tropical grass used for ruminant production. However, it can cause hepatogenous photosensitization, general ill-thrift, and deaths in ruminants due to the presence of steroidal saponins. This study determined the acute and chronic clinico-pathological responses of sheep to graded levels of B. decumbens diet. A total of 30 male crossbred Dorper sheep (six-monthold) used in the study were randomly divided into three treatment groups of 10 sheep each. Treatment 1 (T1), which served as the control group, was fed with Pennisetum purpureum and concentrates, whereas Treatments 2 (T2) and 3 (T3) were fed low (10%) and high (60%) levels of B. decumbens, respectively. The study period was divided into acute (7 days) and chronic (90 days) phases. The rectal temperature, respiratory rate, heart rate, and mucous membrane color were monitored throughout the experiment. At the end of each stage, five animals were selected from each treatment group and euthanized by slaughter to collect organs for gross pathology, organ morphometric and histopathological evaluations. The treated animals did not show significant changes (p>0.05) in rectal temperature, pulse, and respiration rates throughout the study period. However, the mucous membranes were noticeably becoming pale starting from day 60 to 90 in T3 and during the chronic phase (day 90) in T2. There was no lesion or morphometric change in any organ at postmortem examination. At histopathology, both T2 and T3 exhibited mild to moderate necrosis, hemorrhage, congestion, hydropic degeneration and edema (p<0.05) in the liver and brain. In summary, this study has established that both low and high levels of B. decumbens diets cause chronic brain and liver damages in the sheep model. This study can be used for future research on the effects of B. decumbens on grazing animals. [ABSTRACT FROM AUTHOR]

Soil tillage and cover crops impact spontaneous vegetation in agrosystems. Soil tillage destroys seedlings and can affect the soil seedbank. Cover crops compete with naturally occurring spontaneous species. Our aim was to gain insight into how soil tillage (here, the false seedbed technique) and cover crops impact the spontaneous vegetation in fallows preceding banana crops. In a fallowed field in Guadeloupe (French West Indies), two factors were combined in a split-plot design: the soil tillage modality before cover crop sowing (with or without the false seedbed technique) and the cover crop species (Crotalaria spectabilis, Pueraria phaseoloïdes, a 50/50 mix of Brachiaria decumbens + Brachiaria ruziziensis, a spontaneous vegetation control). On a monthly basis, in three permanent quadrats per sub-plot, all spontaneous species were identified and their numbers counted, while calculating the species richness and Shannon's diversity index. The spontaneous vegetation dynamics contrasted depending on the treatment. From 7 months post-sowing the species density, richness and Shannon index were significantly lower in treatments with B. decumbens + B. ruziziensis and P. phaseoloïdes, while in treatments with C. spectabilis, the species density and richness were significantly higher with than without the false seedbed technique. These effects were probably related to differences in the competitive ability of the cover crop used and, to a lesser extent, to the false seedbed effects on the soil seedbank. This is the first study to show that under a tropical climate, sown cover crop species combined with different soil tillage modalities have substantial impacts on the species density, richness and diversity of the spontaneous plant community over a 1-year period. These results could help farmers in their weed control strategies by providing them with a deeper understanding of the effects of practices on the spontaneous plant community. [ABSTRACT FROM AUTHOR]

O objetivo deste estudo foi estudar a fitossociologia das espécies de ervas daninhas em áreas de pastagem cultivadas com Brachiaria decumbens e Cynodon sp. (Tifton 85), no estado do Ceará, no Brasil. A metodologia de inventário quadrado foi utilizada para avaliar a comunidade de ervas daninhas. As amostras de ervas daninhas foram quantificadas e classificadas por família, gênero e espécie, usando livros e chaves de classificação. Os dados de classificação e quantificação das espécies permitiram calcular as seguintes variáveis fitossociológicas: frequência (F), frequência relativa (Fr), densidade (D), densidade relativa (DR), dominância absoluta (DoA), dominância relativa (DoR), importância índice de valores (IVI) e índice de similaridade (IS). A família Amaranthaceae foi aquela com maior intensidade de espécies em ambas as áreas, representada principalmente por Alternanthera tenera colla e Amaranthus viridis. Na área cultivada com B. decumbens, Cyperus rotundus apresentou maiores resultados de frequência, densidade e abundância. Na área de Tifton 85, os physalodes de Nicandra apresentaram maiores valores de densidade e abundância. A semelhança das populações de plantas daninhas em áreas de pastagem foi de 42,11%, com quatro espécies comuns a ambas as áreas.

Copyright of Tropical Grasslands / Forrajes Tropicales is the property of International Centre for Tropical Agriculture - CIAT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

O objetivo com esta pesquisa foi analisar o efeito das estações seca e chuvosa sobre a produção, qualidade do leite (gordura, lactose, proteína, sólidos totais, CTB e CCS) e as variáveis fisiológicas (temperatura retal e superficial e frequência respiratória e cardíaca) de vacas mestiças (holandês/zebu) em lactação, sob regime de pastejo rotacionado em pastagem cultivada, utilizando-se 10 vacas mestiças (holandês/zebu) em lactação, peso vivo médio de 500 ± 30 kg, sendo que no período chuvoso estavam entre o quarto e quinto mês de lactação e no período seco estavam entre o sétimo e oitavo mês de lactação com uma produção média inicial de 18 ± 4kg de leite/vaca/dia, mantendo homogeneidade do lote nas duas estações. Os animais foram mantidos em sistema semi-intensivo de criação, utilizando pastejo rotacionado em pastagem de Brachiaria decumbens, numa área de 3 hectares, onde existia um conglomerado de árvores que propiciavam 5m²/animal de sombra natural, para abrigar os animais nos horários mais quentes do dia. As estações do ano e os horários do dia influenciaram significativamente (P < 0,05) a temperatura do ambiente, umidade relativa do ar e o índice de temperatura de globo negro e umidade. A frequência respiratória e a temperatura superficial foram mais elevadas (P < 0,05) na estação seca e os valores da temperatura retal e frequência respiratória foram similares (P > 0,05) nas estações. A produção e a proteína do leite apresentaram diferença significativa (P < 0,05) em função das estações do ano. Com o auxílio das variáveis fisiológicas (temperatura retal e superficial e frequência cardíaca e respiratória), mesmo assim, as vacas diminuíram sua produção e aumentaram a concentração de proteína no leite.

Abstract Effects of protein supplementation, with and without starch supplementation, on nutritional performance and metabolic characteristics of cattle fed low- and medium-quality tropical forages were evaluated using 4 cannulated steers distributed according to a 4 × 4 Latin square. Experimental periods were divided into two subperiods. In the first subperiod, two animals received low-quality hay and two animals received medium-quality. Supplementation schemes were evaluated in the second subperiod: low-quality hay with protein (300 g of crude protein – CP/d); low-quality hay with protein (300 g CP/d) and starch (225 g/d); medium-quality hay with protein (300 g CP/d); and medium-quality hay with protein (300 g CP/d) and starch (225 g/d) supplementation. Without supplementation, medium-quality forage provided higher intake, digestibility, nitrogen balance (NB) and efficiency of nitrogen utilization (EFNU). Comparing subperiods, supply of supplements depressed medium-quality forage intake, but did not affect low-quality forage intake. Supplementation increased NB, EFNU and serum concentration of IGF1 in animals fed low-quality forage. Protein supplementation increases nitrogen retention in animals, an effect attributed mainly to anabolic stimuli. However, this effect is more prominent when animals are fed low-quality forages. No positive impact on animal metabolism was obtained with combination of supplemental protein and starch.

Identifying forage species that are responsive in regions with marked water deficits is one of the greatest challenges for the sustainable development of agriculture. However, information is still lacking about the persistence response of those pastures and their abilities to produce new tissues at the times of water scarcity. We hypothesized that Brachiaria grass has a tillering capacity during water-stress periods. This study thus examined the tillering capacity and structural characteristics of four Brachiaria brizantha cultivars (Xaraés, Piatã, Marandu, and Paiaguás) and one Brachiaria decumbens cultivar (Basilisk) in the Brazilian semi-arid region during the dry season (September to March). The experiment was laid out in a randomized block design with repeated measures over time in which five treatments were tested in four replicates. Tillering parameters, pasture production, and structural variables were evaluated. There was no interaction effect of cultivar × evaluation period on the tiller appearance (p= 0.1774), mortality (p= 0.1952) or survival (p= 0.4469) rates. The highest tiller appearance and mortality rates were observed in Marandu, while the highest survival rates were found in Marandu and Paiaguás. The index of tiller population stability was higher than or equal to 1.0 in all cultivars. Cultivar Basilisk showed the highest herbage mass yield (4448.0 kg DM ha-1), whereas Basilisk exhibited the highest yields of leaf (1845.9 kg DM ha-1), stem (1676.9 kg DM ha-1), and dead material (925.2 kg DM ha-1). The highest leaf:stem ratio (1.8) was found in Marandu. Cultivar Xaraés had the highest canopy (70.8 cm). The B. brizantha and B. decumbens cultivars evaluated in this study have the potential for cultivation in areas with marked water deficits, as is the case of the Brazilian semi-arid region. Cultivars Marandu, Basilisk, and Paiaguás exhibited the greatest tillering dynamics as well as the highest herbage-mass yield.

The goal of this study is distinguish on remote sensing data, different conservation stage from pasture areas, using laboratorial analysis, orbital images and field spectroscopy, comparing field and laboratory methods. Was studied two pasture areas with grass Brachiaria decumbens, the area 1 without degradation and the area 2 degraded. The orbital sensor changed chosen was Sentinel-2 MSI, and yours images was used on Leaf Area Index (LAI) estimative and in obtaining the reflectance of the canopies, as well as using a field spectrometer. The concentration of chlorophyll was quantified, where the degraded area presented lower values, denoting low force. The LAI computation was efficient in the separation of the degraded area, which presented lower LAI, however the satellite reflectance data did not result as expected, because the degraded area reflected less energy in the red, however the recognition of coverage patterns was observed mainly in area without degradation. The chlorophyll content in the canopies was compared with reflectance obtained with the field spectrometer, and in the reflectance graphics presented particular features. However, the reflectance spectra were better analyzed after applying the information extraction techniques, in which the spectral derivative and the removal of the continuum were efficient to differentiate the areas, confronting with the chemical data

The beneficial effects of feeding rabbits with forages have been recommended. However, limited study has been made on feeding values of locally available forages in rabbits. Therefore, an experiment was conducted to evaluate the effect of Asyastasia gangetica and Brachiaria decunbens on intake, digestibility, and growth performance of rabbits. Twelve rabbits were distributed into three diets: (i) 100% commercial pellet as control (T1), (ii) 50% pellet plus Asyastasia gangetica ad libitum (T2), and (iii) 50% pellet plus Brachiaria decumbens ad libitum (T3). Daily feed intake, nutrient digestibility, weekly body weight, and feed conversion ratio (FCR) were measured. Intakes of total dry matter (DM) (121.2-134.3 g/d) and organic matter (OM) (115.1-132.5 g/d) were similar (p>0.05) for all the groups. The crude protein (CP) intake of rabbits fed with T1 (10.1 g/d) and T3 (9.6 g/d) diets was similar (p>0.05), but lower (p<0.05) than T2 (14.1 g/d) diet. Ether extract intake of rabbits fed with T2 (2.9 g/d) and T3 (3.9 g/d) diets was similar (p>0.05), but lower (p<0.05) than T1 (5.1 g/d) diet. Neutral detergent fibre (NDF) intake was higher (p<0.05) for rabbits fed with T3 (55.8 g/d) diet followed by T2 (41.7 g/d) and T1 (31.7 g/d) diets. There were no differences (p>0.05) on the digestibilities of DM, OM, and CP among treatments. Total weight gain and daily weight gain were higher (p<0.05) for rabbits fed with T1 (568 and 11.0 g) and T2 (468 and 9.0 g) diets than T3 (155 and 3.3 g) diet, respectively. The lowest FCR was obtained with T1 (12.3) and T2 (13.9) diets, whereas the highest was obtained with T3 (30.3) diet. In conclusion, diet containing Asyastasia gangetica showed more benefits in terms of CP and NDF intakes, weight gain and FCR than the diet containing Brachiaria decumbens. A combination of concentrate and Asyastasia gangetica is recommended as a partial replacement for concentrate in rabbit production. [ABSTRACT FROM AUTHOR]

Eucalyptus harvests generate residues that remain on the soil and affect the efficacy of preemergent herbicides in the following planting cycle. The objective of this work was to evaluate the dynamics of flumioxazin, sulfentrazone, and isoxaflutole herbicides applied on different amounts and compositions of eucalyptus harvest residues subjected to different rainfall depths; and evaluate the weed control effectiveness of these herbicides when applied under these conditions. A LC–MS/MS system was used for the evaluations and the results showed that a cumulative rainfall of 50 mm was sufficient for the maximum removal of herbicides from the eucalyptus residues, regardless of the residue composition. The amount of the flumioxazin, sulfentrazone, and isoxaflutole herbicides that reached the soil was lower in the treatment with the highest amount of eucalyptus harvest residue used (40 Mg ha−1). The greatest amount of herbicide reaching the soil was found with the use of 15 Mg ha−1 of residues without presence of bark. The highest amount of residue used (40 Mg ha−1) reduced the control of Brachiaria decumbens by sulfentrazone and isoxaflutole. The control of Commelina benghalensis was inefficient (> 80%) in the treatment with 15 Mg ha−1 of residues without barks, regardless of the herbicide. Sulfentrazone controlled Ipomoea grandifolia (> 90%) under the evaluated residue conditions. Spermacoce latifolia and Sida rhombifolia were controlled by all herbicides in the evaluated residue conditions. Isoxaflutole controlled Panicum maximum in all residue conditions. The choice between the herbicides depends on the residue condition, rainfall regime, and weed species to be controlled. [ABSTRACT FROM AUTHOR]

This research was aimed at studying the in vitro ruminal biohydrogenation (BH) of C18 fatty acids (FA) in mixtures of Indigofera zollingeriana and Brachiaria decumbens. Four combinations of experimental rations of I. zollingeriana : B. decumbens were tested i.e., IZ 1 (45%:45%), IZ 2 (60%:30%), IZ 3 (75%:15%), and IZ 4 (90%:0%). The remaining 10% in in each ration was rice bran. The experimental design was based on a completely randomized design with five replicates. Results revealed that there was a statistically significant difference (P<0.01) in the composition of C18 unsaturated FA (UFA) and saturated FA (SFA) for each in vitro incubation period of 1, 2, 4, 8 and 24 h. The highest accumulation of C18 UFA at 24 h was observed in the incubation of IZ 4 (19.87%). The BH of C18:3, C18:2, and C18:1 showed no differences (P>0.05). Composition of C18:0 after incubation showed a significant difference (P<0.01) with the lowest composition was observed in IZ 2 (22%). In conclusion, combination of I. zollingeriana and B. decumbens at different ratio has minor inhibition effect on BH of C18 UFA. [ABSTRACT FROM AUTHOR]

Identifying forage species that are responsive in regions with marked water deficits is one of the greatest challenges for the sustainable development of agriculture. However, information is still lacking about the persistence response of those pastures and their abilities to produce new tissues at the times of water scarcity. We hypothesized that Brachiaria grass has a tillering capacity during water-stress periods. This study thus examined the tillering capacity and structural characteristics of four Brachiaria brizantha cultivars (Xaraés, Piatã, Marandu, and Paiaguás) and one Brachiaria decumbens cultivar (Basilisk) in the Brazilian semi-arid region during the dry season (September to March). The experiment was laid out in a randomized block design with repeated measures over time in which five treatments were tested in four replicates. Tillering parameters, pasture production, and structural variables were evaluated. There was no interaction effect of cultivar × evaluation period on the tiller appearance (p= 0.1774), mortality (p= 0.1952) or survival (p= 0.4469) rates. The highest tiller appearance and mortality rates were observed in Marandu, while the highest survival rates were found in Marandu and Paiaguás. The index of tiller population stability was higher than or equal to 1.0 in all cultivars. Cultivar Basilisk showed the highest herbage mass yield (4448.0 kg DM ha-1), whereas Basilisk exhibited the highest yields of leaf (1845.9 kg DM ha-1), stem (1676.9 kg DM ha-1), and dead material (925.2 kg DM ha-1). The highest leaf:stem ratio (1.8) was found in Marandu. Cultivar Xaraés had the highest canopy (70.8 cm). The B. brizantha and B. decumbens cultivars evaluated in this study have the potential for cultivation in areas with marked water deficits, as is the case of the Brazilian semi-arid region. Cultivars Marandu, Basilisk, and Paiaguás exhibited the greatest tillering dynamics as well as the highest herbage-mass yield. [ABSTRACT FROM AUTHOR]

Introduction: Due to its current coverage, the root biomass of tropical pastures is of vital importance for the terrestrial carbon storage, but its estimation has been mainly indirect and with a very wide range of values. Objective: To document at national and global level as well as compare, the root carbon stocks extracted directly from two grasslands of different growth type and origin. Methods: The biomass and root carbon stocks were directly extracted from two tropical pastures with more than 40 yr of age. The biomass and total carbon, one native with stoloniferous growth (Paspalum notatum) and one introduced with growth in tillers (Urochloa decumbens) were measured. The study was conducted between August and October 2016. Three plots of 1 600 m2 each were selected per pasture, with 10 sub-squares (4 m2 each) in each plot to determine the floristic composition, aboveground biomass and C. The biomass and root C were estimated by hand in three trenches (1.50 m x 0.50 m x 1.0 m) per plot. The organic carbon content was determined with the ignition method at an average temperature of 550 °C for 3 hours. For the statistical analysis, a two-factor ANOVA was used, where one factor was the treatments that were the type of pasture (2) and the other factor was the section of the grass (above and belowground). Results: The floristic composition of the two types of pasture was different due to its management history. On average, 28.25 Mg ha-1 of total C was estimated for the locality. The native pasture of stoloniferous growth P. notatum yields almost three-fold more biomass (42.5 MgC ha-1) than the introduced with growth in tillers U. decumbens (14 MgC ha-1) due to the radicular storage (38.5 vs. 11.46 MgC ha-1). Seventy-four point five percent of the carbon in P. notatum was located in the radicular part and 25.5 % above-ground, while in U. decumbens 56.5 and 43.5 %, respectively. Conclusions: P. notatum accumulated more total and radicular biomass and carbon than U. decumbens. The best adaptation of the native grass as well as the morphology of its root system may explain this difference. Ninety six percent of the biomass and root C is found in the first 0.50 m depth. Due to the contribution of its radicular portion, tropical pastures can constitute important reservoirs of terrestrial carbon considering its extension nowadays. [ABSTRACT FROM AUTHOR]

The selection of sexual genitors in Urochloa decumbens breeding is dependent upon the performance of their progeny for several traits simultaneously. Thus, our objectives were to (i) compare the efficiency of indices to select genitors of U. decumbens, (ii) evaluate the genetic gains obtained through selection intensities, and (iii) evaluate the multivariate pattern of progenies through principal components analysis (PCA). For this purpose, 1415 hybrids from 75 progenies of full siblings were evaluated at Embrapa Beef Cattle (Brazil) using seven cuts for dry matter production, regrowth, protein, fiber, lignin, and percentage digestibility. Statistical analyses were performed using mixed models and PCA. The direct selection for dry matter production provided a 37.51% genetic gain. Agronomic traits using indices provided greater gains. Genitors selected using PCA Biplot were similar to selections using indices. Indices and PCA were proven to be an excellent tool to select multi-traits in U. decumbens. [ABSTRACT FROM AUTHOR]

Brachiaria decumbens (signal grass) is a highly productive tropical grass that is widespread in some tropical countries due to its adaptation to a wide range of environments and soil types. However, a limiting factor for the use of this grass is its toxicity from steroidal saponins. Sporadic outbreaks of hepatogenous photosensitization in ruminants grazing on this grass have been reported. Sheep are more susceptible than other animal species and the young are more susceptible than adults. This review article will critically shed light on the B. decumbens profile, its toxic compounds, mechanisms, clinical responses, blood profile alterations, pathological changes, and acute phase responses related to signal grass intoxication. Further research is needed to integrate new findings on B. decumbens intoxication with previous preventive and therapeutic trials to minimize or remove its deleterious toxic effect. [ABSTRACT FROM AUTHOR]

Biochar has been used as an amendment for disturbed soils. However, the changes of the rhizobacterial community after the biochar addition in mine soils, has not yet been elucidated. The aim of this study was to evaluate the response in the rhizobacterial communities of Brachiaria decumbens during different reclamation processes of coal mining using biochar. Five treatments were carried out: control, mine soil + biochar, mine soil + biochar + Azospirillum brasilense, mine soil + biochar + arbuscular mycorrhizal fungal + Mortierella sp. DNA from the rhizospheric soil was sequenced by Ion Torrent. The relative abundance in each sample was calculated. The Proteobacteria (70%) and Actinobacteria (23%) phyla dominated the rhizobacterial community composition during the establishment time. Seven months after seeding, Actinobacteria decreased significantly, while Proteobacteria increased. The Acidobacteria phylum was higher in the control. There was a higher abundance of Proteobacteria with the biochar treatments than for the control, thus the baseline for the rhizobacterial community changes induced by biochar was provided. The alpha diversity index showed the effect of biochar on the diversity and dominance of the rhizobacterial communities. The hierarchical clustering tree showed a correlation between the treatments with biochar, and a significant differentiation between these and the control treatment. [ABSTRACT FROM AUTHOR]

Copyright of Agronomía Colombiana is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: the use of creep-feeding combined with the correct management of pastures has been one of the main tools of nutritional management in cattle. Objective: to evaluate the effects of supplementation with different protein regimes on the metabolic profile in grazing suckling male calves. Methods: fifty suckling Nellore male calves with average initial body weight (BW) of 114 ± 2.4 kg and 105 ± 3.0 days age were used and distributed in a completely randomized design in two treatments and 25 replicates. The protein regimens evaluated were low protein (LOW)-supplement with 150 g CP/kg DM and; High protein (HIGH) - supplement with 300 g CP/kg DM. The supplements were composed of soybean meal‚ cornmeal‚ wheat meal‚ mineral mixture‚ and molasses‚ and provided in amounts of 6 g/kg BW. The animals were subjected to 78 experimental days and kept in eight 5 hectares paddocks each‚ formed by Brachiaria decumbens and equipped with drinkers and feeders. All animals had unrestricted access to water. Blood samples were collected to quantify levels of urea‚ albumin‚ globulins‚ total protein‚ glucose‚ triglycerides‚ and insulinlike growth factor 1 (IGF-1). Globulin concentrations were calculated by the difference between total protein and albumin concentration. Results: no treatment effect was observed (p > 0.10) on concentrations of glucose (77.6 vs 81.6 mg/mL)‚ triglycerides (32.8 vs 39.2 mg/mL)‚ total proteins (6.52 vs 6.67 g/dL)‚ globulin (3.28 vs 3.25 g/dL) and IGF-1 (424 vs 441 nm/ mL); while the albumin (3.24 vs 3.42 g/dL) and SUN (10.2 vs 15.7 mg/dL) concentrations did show significant differences (p < 0.05)‚ being higher in the calves supplemented with higher level of crude protein. Conclusions: supplementation with 150 g CP/kg DM in the amount of 6 g/kg PC is recommended for lactating beef calves during the rainy season and rainy-dry transition. [ABSTRACT FROM AUTHOR]

Background: to ensure continuous calves' growth, the supply of supplements is necessary to impact the animals' tissue response. Objective: the aim of this study was to evaluate the effects of supplementation with different protein regimens on performance in suckling beef calves. Methods: fifty suckling Nellore calves with average initial body weight (BW) of 114 ± 2.4 kg and 105 ± 3.0 days age were used and distributed in a completely randomized design with two supplementation treatments: Low protein (LOW) and High protein (HIGH). The supplements were composed of soybean meal, cornmeal, wheat meal, mineral mixture, and molasses, containing 150 g CP/kg dry matter (DM) and 300 g CP/kg DM for LOW and HIGH respectively, and provided in amounts of 6 g/kg BW. The animals underwent 78 experimental days, and were kept in eight 5 hectares paddocks each, formed by Brachiaria decumbens and equipped with drinkers and feeders. For productive performance evaluation, all calves were weighed at the beginning and end of the experiment after 14 h for solids fasting. Also, on the 78th-day experimental carcass images were obtained by ultrasound between the 12th and 13th ribs over the longissimus muscle to measure the ribeye area and backfatthickness on the Longissimus muscle (FAT-L), and between the ischium and pubis to the backfat-thickness on the rump (FAT-R). Biopsies of Longissimus dorsi muscle were performed at 75 days to measure the number and diameter of muscle fibers. Results: no difference (p > 0.05) was observed for average daily gain (LOW = 0.98 vs HIGH = 1.00 kg/d) or final BW (LOW = 191 vs HIGH = 193 kg) throughout the experiment. Likewise, no effect (p > 0.05) of the amounts of protein supplementation was verified on ribeye area (LOW = 36.7 vs HIGH = 38.8 cm2), FAT-L (LOW = 1.38 vs HIGH = 1.54 mm), FAT-R (LOW = 2.06 vs HIGH = 2.30 mm), or number (LOW = 141 vs HIGH = 142) and diameter (LOW = 29.2 vs HIGH = 30.9) of muscle fibers. Conclusions: supplementation with 150 g CP/kg DM in the amount of 6 g/kg BW is recommended for suckling beef calves in grazing. [ABSTRACT FROM AUTHOR]

This study aims at assessing the influence of mineral fertilization and biofertilizer from liquid swine manure (LSM) in productivity, levels of crude protein (CP), neutral detergent fiber (NDF) and Acid Detergent Fiber (ADF) of Urochloa decumbens. The experiment was carried out in a red Latosol under a Urochloa decumbens pasture, in a state of degradation with loss of vigor and forage productivity. The delineation chosen for this study was randomized blocks with six treatments (control without fertilization, control with use of mineral fertilizer and four unique concentrations of liquid swine manure biofertilizer (61 m3 ha-1, 121 m3 ha-1, 181 m3 ha-1, 241 m3 ha-1)). The application of residue has been split in two times on the surface of the soil, by means of a distributor of liquid waste with a fan-shaped application. Yield and bromatological features were evaluated for two years. Fertilization with LSM can fully replace mineral fertilizing in Urochloa decumbens pasture systems, resulting in an increase, as a result, in the dry mass yield from the dosage of 121 m3 ha-1 and the reduction in fiber content in neutral and acid detergent. The increments in yield were observed in the second year, while improvement in bromatological quality was observed from the first application of LSM.

The objective of study was to evaluate the productive response of crossbred cows grazing on Brachiaria decumbens pasture to supplementation with an experimental concentrates (CEXP) with or without addition of Saccharomyces cerevisiae (SC). Four milking Brown Swiss × Zebu cows were utilized 4×4 Latin square design. Treatments were T1= 3 kg of CEXP; T2= 2 kg of CEXP; T3= 2 kg of CEXP + 10 g of SC; and T4= 3 kg of commercial concentrate as control treatment. CEXP was 63% ground maize, 25% canola meal, 10% molasses and 2% urea. All cows received 3 kg of maize silage plus free access to grazing Brachiaria decumbens. Experimental periods consisted of 21 days each. Chemical analysis was performed on Brachiaria decumbens grass, maize silage and the concentrate supplements. Variables evaluated were milk yield, protein and fat content in milk, live weight and body condition score (BCS). Mean milk yield was 6.6 kg/cow/day, with no differences among treatments, nor there were differences in live weight or BCS. However, significant differences were found in protein and fat in milk, with lower values for these components in T2 and T3 than in T1 and T4. The addition of different levels of inclusion had no effect on milk yield, live weight and body condition, as well as fat and protein in milk.

Brazil is the largest world producer, consumer and exporter of forage grass seeds. Urochloa decumbens Stapf. species is the second in importance in the Brazilian market of seeds of tropical forage grasses. Seeds are harvested by the soil sweeping method and, in addition to other impurities, harvested lots can present weed seeds, which makes seeds unfeasible for commercialization. The aim of the present study was to evaluate differences in the physical quality and viability of Urochloa decumbens cv. Basilisk seeds produced in different production fields. Fifteen U. decumbens seed lots from the State of São Paulo (1 lot in the municipality of Cássia dos Coqueiros and 3 lots in the municipality of Santo Antônio da Alegria), Minas Gerais (2 lots in the municipality of Tupaciguara, 2 lots in the municipality of Unaí, 2 lots in the municipality of Chapada Gaúcha and 3 lots in the municipality of Monte Santo de Minas), Goiás (1 lot in the municipality of Jataí) and Mato Grosso (1 lot in the municipality of Primavera do Leste) were evaluated by means of the following parameters: water content, viability by tetrazolium test, purity, determination of other seeds by number and weight of one thousand seeds. A completely randomized design was used, and when significant, the means of treatments were compared by the Scott Knott test at 5% probability. The fields of the different regions produce U. decumbens seeds with high variability in physical quality. U. decumbens seeds with the highest physical quality and viability were produced in Cassia dos Coqueiros - SP.

Background Brazil has the largest commercial herd of ruminants with approximately 211 million head, representing 15% of world’s beef production, in an area of 170 million hectares of grasslands, mostly cultivated with Brachiaria spp. Although nutrient reduction due to increased atmospheric carbon dioxide (CO2) concentration has already been verified in important crops, studies evaluating its effects on fiber fractions and elemental composition of this grass genus are still scarce. Therefore, a better understanding of the effects of elevated CO2 on forage quality can elucidate the interaction between forage and livestock production and possible adaptations for a climate change scenario. The objective of this study was to evaluate the effects of contrasting atmospheric CO2 concentrations on biomass production, morphological characteristics, fiber fractions, and elemental composition of Brachiaria decumbens (cv. Basilisk). Methods A total of 12 octagonal rings with 10 m diameter were distributed in a seven-ha coffee plantation and inside each of them, two plots of 0.25 m2 were seeded with B. decumbens (cv. Basilisk) in a free air carbon dioxide enrichment facility. Six rings were kept under natural conditions (≈390 μmol mol−1 CO2; Control) and other six under pure CO2 flux to achieve a higher concentration (≈550 μmol mol−1 CO2; Elevated CO2). After 30 months under contrasting atmospheric CO2 concentration, grass samples were collected, and then splitted into two portions: in the first, whole forage was kept intact and in the second portion, the leaf, true stem, inflorescence and senescence fractions were manually separated to determine their proportions (%). All samples were then analyzed to determine the fiber fractions (NDF, hemicellulose, ADF, cellulose, and Lignin), carbon (C), nitrogen (N), potassium (K), calcium (Ca), sulfur (S), phosphorus (P), iron (Fe), and manganese (Mn) contents and N isotopic composition. Results Elevated atmospheric CO2 concentration did not influence biomass productivity, average height, leaf, stem, senescence and inflorescence proportions, and fiber fractions (p > 0.05). Calcium content of the leaf and senescence portion of B. decumbens were reduced under elevated atmospheric CO2 (p < 0.05). Despite no effect on total C and N (p > 0.05), lower C:N ratio was observed in the whole forage grown under elevated CO2 (p < 0.05). The isotopic composition was also affected by elevated CO2, with higher values of δ15N in the leaf and stem portions of B. decumbens (p < 0.05). Discussion Productivity and fiber fractions of B. decumbens were not influenced by CO2 enrichment. However, elevated CO2 resulted in decreased forage Ca content which could affect livestock production under a climate change scenario.

This study aimed to evaluate the control and susceptibility of signalgrass and ruzigrass in initial growth under different rates of glyphosate and fluazifop-p-butil. The treatments were distributed in a 2 × 6 factorial design, with five repetitions, being two grasses: Brachiaria decumbens cv. Basilisk (signalgrass) and B. ruziziensis (ruzigrass) with six doses of herbicides: 0.00; 0.25; 0.50; 1.00; 1.5 and 2.00 times the commercial dose recommended by manufacturers. At 7, 15, 21, and 30 days after herbicide application (DAA) were evaluated the intoxication in signalgrass and ruzigrass, visually. The glyphosate toxicity was of 100% in both plants, signalgrass and ruzigrass, even at the lowest dose (90 g ha-1), so it can control effectively these species in early growth stage. It was observed that the plants exposed to fluazifop-p-butil showed regrowth only in the doses to 100 g ha-1 and 50 g ha-1 for signalgrass and ruzigrass, respectively. These results confirm the effectiveness of this herbicide molecule in the control of these two species from doses of 200 g ha-1 and 100 g ha-1 for signal grass and ruzigrass, respectively. [ABSTRACT FROM AUTHOR]

Abstract The potential of the symbiosis between plants and arbuscular mycorrhizal fungi (AMF) to reduce emissions of the greenhouse gas N 2 O has gained scientific attention in the last years. Given the high nitrogen (N) requirements of AMF and their role in plant N uptake, they may reduce the availability of mineral N that could be subject to N 2 O emissions and leaching losses. We investigated the impact of AMF on the growth of tropical grass Brachiaria decumbens Stapf. and on N 2 O released after fertilization with urea in a mesocosm study. To evaluate the role of nitrification in N 2 O emissions, we used nitrification inhibitor dicyandiamide (DCD). The study included a full-factorial design (n = 6) with two AMF treatments (with and without AMF inoculation) and three fertilization treatments (control, urea and urea + DCD), applied after 92 days of growth. Plant growth, soil properties and N 2 O emissions were measured during the following 2 weeks and the abundance of nitrifiers was quantified one and two weeks after fertilization. The production of N 2 O increased after urea application but only without DCD, indicating the importance of nitrification in N 2 O emissions. The emissions of N 2 O after urea application were reduced by 46% due to the presence of AMF. Nevertheless, the abundance of ammonia-oxidizing bacteria (AOB) was increased by urea and AMF, while plant growth was reduced by the AMF. The increased root:shoot ratio of the biomass in AMF pots suggests competition between AMF and plants. This study demonstrated that immobilization of N by AMF can reduce N 2 O emissions after fertilization, even when plant growth is reduced. The inverse relationship between (higher) AOB abundance and (lower) nitrification rates suggests that changes in the activity of AOB, rather than abundance, may be indicative of the impact of the AMF- Brachiaria symbiosis on N cycling in tropical grasslands. Alternatively, the difference between N 2 O emissions from AMF and non-AMF pots may be explained by increased reduction of N 2 O in the presence of AMF. Longer-term studies are needed to verify whether the effects of AMF on N 2 O emissions and/or plant growth persist over time or are limited to initial immobilization of N by AMF in N-limited systems. Highlights • The impact of AMF on nitrous oxide emissions was assessed in a pot experiment. • AMF reduced the nitrous oxide emissions after fertilization with urea. • The abundance of AOB was increased by AMF. • Plant growth was reduced by AMF while MBN was increased. [ABSTRACT FROM AUTHOR]

Silvopastoral system (SPS) has been suggested to ensure sustainability in animal production systems in tropical ecosystems. The objective of this study was to evaluate the productive and nutritive value traits of Brachiaria decumbens and performance of dairy heifers in SPS and open pasture (OP) during the summer and autumn of two consecutive years in the SPS and OP (17th and 18th years after establishment). Experimental design was a randomized complete block with two treatments (SPS and OP) and three replications in subdivided plots with repeated measures in time. There was reduction in the tiller population density, total and green forage mass, and total and green forage bulk density in the SPS when compared to the OP in the summer. In the autumn, no difference was observed between the systems. Shading in SPS increased crude protein content of the grass pasture by 25% and 33% when compared to the OP during the first and second experimental years, respectively, and reduced neutral detergent fibre content. However, it did not change acid detergent fibre or lignin content. OP provided higher stocking rate and weight gain per area than the SPS. Average daily gain was higher in the OP in the second experimental year. Severe shading conditions should be avoided, because in the long‐term they may threaten the persistence and sustainability of pasture in the SPS. It is recommended to plant a low density of trees or implement management strategies of the tree component by either thinning or pruning over the years after planting. [ABSTRACT FROM AUTHOR]

Abstract The Llanos region of Colombia represents one of the last large agricultural frontiers and is undergoing a rapid conversion from naturalized savanna to intensive agriculture with high agrochemical inputs and tillage. This massive land-use conversion has considerable impact on ecosystem services and biodiversity, particularly soil macrofauna, yet the full implications of this land-use shift for long-term agroecosystem productivity are poorly understood. To better elucidate potential land-use change impacts on agricultural production we used experimental microcosms in the greenhouse to evaluate how the common earthworm, Pontoscolex corethrurus, influences plant growth, nutrient uptake, and key soil properties relative to the application of lime and P fertilizer, both common soil fertility amendments in the region. Additionally, we aimed to explore the potential for interactions between earthworms and these amendments across distinct plant types, the grass Brachiaria decumbens and the legume Phaseolus vulgaris , which display different rooting patterns and nutrient acquisition strategies. Earthworms increased the biomass production of B. decumbens by 180% and N uptake by more than 240%, while P fertilizers and lime additions increased total biomass by less than 30% each for B. decumbens. Effects on P. vulgaris were similar, but less pronounced with earthworms increasing total biomass production by 35% and total plant N content by 70%, while neither lime nor P alone significantly influenced total biomass or N uptake. However, a significant interaction between earthworms and lime enhanced total biomass N content of P. vulgaris by more than 150% relative to microcosms without P. corethrurus , suggesting that earthworms can greatly enhance the efficacy of lime in soils. Additionally, we found that earthworms greatly improved soil aggregation, but only in the presence of plants, and that this effect was most prominent in microcosms with P. vulgaris. When testing treatment effects on soil P availability, only fertilizer P additions significantly influenced resin P, but not microbial biomass P. Our findings suggests the importance of developing management strategies that promote the activity and diversity of earthworms and other soil biota as a means to enhance crop productivity, resource use efficiency and a range of soil-based ecosystem services in the Llanos region and beyond. Highlights • Earthworms enhance plant growth more than lime or P fertilizer. • Lime only improves plant N uptake in the presence of earthworms. • Earthworms enhance soil structure, but only in the presence of growing plants. • Farm management should consider soil biological communities to optimize resource use efficiency. [ABSTRACT FROM AUTHOR]

Background: Brazil has the largest commercial herd of ruminants with approximately 211 million head, representing 15% of world's beef production, in an area of 170 million hectares of grasslands, mostly cultivated with Brachiaria spp. Although nutrient reduction due to increased atmospheric carbon dioxide (CO2) concentration has already been verified in important crops, studies evaluating its effects on fiber fractions and elemental composition of this grass genus are still scarce. Therefore, a better understanding of the effects of elevated CO2 on forage quality can elucidate the interaction between forage and livestock production and possible adaptations for a climate change scenario. The objective of this study was to evaluate the effects of contrasting atmospheric CO2 concentrations on biomass production, morphological characteristics, fiber fractions, and elemental composition of Brachiaria decumbens (cv. Basilisk). Methods: A total of 12 octagonal rings with 10 m diameter were distributed in a seven-ha coffee plantation and inside each of them, two plots of 0.25 m2 were seeded with B. decumbens (cv. Basilisk) in a free air carbon dioxide enrichment facility. Six rings were kept under natural conditions (≈390 mmol mol-1 CO2; Control) and other six under pure CO2 flux to achieve a higher concentration (≈550 mmol mol-1 CO2; Elevated CO2). After 30 months under contrasting atmospheric CO2 concentration, grass samples were collected, and then splitted into two portions: in the first, whole forage was kept intact and in the second portion, the leaf, true stem, inflorescence and senescence fractions were manually separated to determine their proportions (%). All samples were then analyzed to determine the fiber fractions (NDF, hemicellulose, ADF, cellulose, and Lignin), carbon (C), nitrogen (N), potassium (K), calcium (Ca), sulfur (S), phosphorus (P), iron (Fe), and manganese (Mn) contents and N isotopic composition. Results: Elevated atmospheric CO2 concentration did not influence biomass productivity, average height, leaf, stem, senescence and inflorescence proportions, and fiber fractions (p > 0.05). Calcium content of the leaf and senescence portion of B. decumbens were reduced under elevated atmospheric CO2 (p < 0.05). Despite no effect on total C and N (p > 0.05), lower C:N ratio was observed in the whole forage grown under elevated CO2 (p < 0.05). The isotopic composition was also affected by elevated CO2, with higher values of d15N in the leaf and stem portions of B. decumbens (p < 0.05). Discussion: Productivity and fiber fractions of B. decumbens were not influenced by CO2 enrichment. However, elevated CO2 resulted in decreased forage Ca content which could affect livestock production under a climate change scenario. [ABSTRACT FROM AUTHOR]

A simulated grazing system was developed, using a total of 2.66 hectares, established with the variety Brachiaria decumbens vc. Basilisk; with the objective of studying their performance under dry conditions and without fertilization, subjected to two grazing intensities (GI): GI1 = 75 and GI2 = 150 LAU ha-1 day-1, during the rainy period. It was worked with 20 crossbred Siboney dairy cows between the second and third lactation (10 animals treatment-1), the animals grazed 15 hours a day. The areas under study showed an increase (P <0.05) in the Brachiaria proportion, in 7.9 and 13.2 %, for 75 and 150 LAU ha-1 day-1, respectively. The areas subjected to the highest intensity, showed higher availability of DM ha-1 paddock-1 (P <0.01) in 39.9 % (1 831.05 vs 2 562.11 kg DM ha-1 rotation-1, for 75 and 150 LAU ha-1 day-1, respectively); likewise, the grass yield was favored (P <0.05) in 23.9 % when it was submitted to 150 LAU ha-1 day-1. There were not differences in the bromatological composition of the grass. The obtained results, under these conditions, show that the Basilisk grass variety, subjected to grazing intensity of 150 LAU ha-1 day-1, maintains higher stability and likewise showed higher availability and grass yield, not affecting the bromatological quality of it. [ABSTRACT FROM AUTHOR]

Highlights • Photosensitization in naive sheep grazing B. decumbens under full sunlight or silvopasture was evaluated. • B. decumbens is highly toxic to sheep not adapted to grazing (naïve). • Protodioscin content in B. decumbens was higher under full sunlight than in silvopasture. • Silvopasture shading does not prevent photosensitization in naive sheep grazing B. decumbens. Abstract The work consisted of the evaluation of photosensitization in sheep grazing signal grass (Brachiaria decumbens) in a silvopastoral system or under full sunlight for 60 days in the summer. We hypothesized that shade provided by trees in the silvopastoral system prevents or alleviates the classic symptoms of photosensitization in grazing sheep and affects the concentration of the saponin protodioscin in signal grass. Twenty naïve crossbred sheep (Dorper x Santa Ines) were used in a randomized block design, with two blocks and five animals per block. Animals in both silvopastoral and full sun treatments grazed B. decumbens , and animals in both treatments presented with clinical symptoms, alterations in the liver, and increased serum levels of gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST), and bilirubin over the duration of the experiment. Although the protodioscin content of B. decumbens in the silvopastoral system was lower than in the full sun treatment, it was sufficient to cause secondary photosensitization in the animals. The natural shading provided by the silvopastoral system does not prevent or ameliorate photosensitization symptoms in young naïve sheep grazing on B. decumbens. [ABSTRACT FROM AUTHOR]