Brachiaria Decumbens Cv Research Articles

Methods for prediction of morphophysiological variables of Brachiaria decumbens grass

AbstractThe purpose of this study was to evaluate different methodologies used in the field in order to find the one that could most effectively relate to the morphophysiological condition of Brachiaria decumbens cv. Basilisk (syn. Urochloa decumbens cv. Basilisk Stapf R.D. Webster). Two light interception frequencies (LI, 85% and 95%) and two defoliation intensities were adopted as targets for the residual leaf area index (RLAI 1.3 and 1.8). The treatments consisted of evaluating different methods of measuring the canopy height (CH) through its ability to correlate with the morphophysiological variables of species B. decumbens cv. Basilisk. High correlations between the methods CH, compressed height (CHe), weighted height 1 (WH1) and weighted height 8 (WH8) were observed mainly with the variables total forage biomass (TFB) and leaf area index (LAI) in both residual and pre‐grazing conditions. The path analysis showed degrees of multicollinearity, which determined the use of the “k” constants in order to correct the distortions of the diagonal elements of the correlation matrix X'X. Path analysis provided direct cause/effect indexes on TFB using LAI = 0.1435, photosynthesis (A) = −0.1061, CH = 0.1616, CHe = 0.0913, WH1 = 0.1386 and WH8 = 0.0575; on LAI using CH = 0.2404, CHe = 0.2164, WH1 = 0.2307 and WH8 = 0.2183; and on photosynthesis rate (A) using LAI = 0.2895, CH = 0.0203, CHe = −0.1170, WH1 = 0.0352 and WH8 = 0.0937. Similarity was observed between intercepts and slope coefficients for TFB prediction using CH, CHe, WH1 and WH8, providing mean values of 1069.57 and 204.06, respectively. Methods CH and WH1 presented a significant correlation with most morphophysiological variables and can be used to quantify TFB and LAI, while CH and WH8 can be used only for TFB.

How does the initial sward height and the grazing period influence the spatial variability of vegetation in deferred signal grass pastures?

The objective of this study was to evaluate the spatial variability of structural characteristics of deferred pastures of Brachiaria decumbens cv. Basilisk (signal grass) subjected to associations of sward heights (10, 20, 30, and 40 cm) at the beginning of deferment and grazing periods (1, 28, 56, 85, and 113 days). The experiment was arranged in a split-plot and completely randomized-block design with two replicates. Pastures remained deferred from March to June 2010. From June to the beginning of October 2010, deferred pastures were utilized by steers under continuous grazing and at a fixed initial stocking rate of 3.5 AU ha-1. At the beginning of the deferment, the coefficient of variation (CV) for pasture height was reduced linearly with the pasture height. During the grazing period, in the winter, the CV for pasture height was not influenced by initial pasture height; however, it responded quadratically to the grazing period, with a maximum value of 36.4% at 71 days of the period of utilization. The CV for tiller height was reduced linearly with pasture height at the beginning of deferment but increased linearly along with the grazing period. The initial pasture height did not change the CV of the falling index. However, the latter was quadratically influenced by the grazing period, with a maximum value of 59.5% at 67 days of the utilization period. Signal grass pastures deferred at a lower height have a higher spatial variability of the vegetation. In the grazing period, there are changes in the spatial variability of the vegetation of the deferred signal grass.

Reclamation of post-tin mining areas using forages: A strategy based on soil mineralogy, chemical properties and particle size of the refused materials

The physical and chemical properties of refused materials in post-mining areas have received in-depth attention, while the mineralogy as a driver of the potential nutrient reserve has been ignored in reclamation practices. The objective of the study was to evaluate mineralogical, chemical, and physical properties and heavy metals of refused materials (spoil and tailings) as the basis for reclamation. Seven representative soil profiles were described and sampled to a depth of 130 cm for various soil analyses and to assess soil limiting factors for crop growth. Eleven forage species were tested in a field plot trial and their adaptability and biomass production against extreme limiting soil properties were evaluated for two consecutive growing seasons. Results showed that tin mining has drastically altered the soil texture from sandy clay loam under native conditions to loamy sand and sand under post-tin mining, resulting in serious unfavourable conditions for crop growth. Potential nutrient reserves have been depleted as revealed by the dominance of quartz minerals with small amounts of tourmaline, opaque minerals, zircon and garnet. Total elemental analysis using X-ray fluorescence (XRF) showed extreme high SiO2 content (92–96%) associated mainly with the dominance of quartz in the mineral constituents, and extremely low contents of Ca, Mg, P, K and S expressed as oxides (<0.2% altogether). This suggests that all nutrients are a severe constraint for crop growth. Among the analyzed total heavy metals, Cr2O3 contents were high (204–286 mg kg−1), while SnO contents were low (0–153 mg kg−1). However, the health risk is negligible because they were preserved in the structure of host minerals. Rehabilitation of post-tin mining was successfully performed using various forage types by implementing “a pot planting point system” accompanied by animal manure and complete fertilizer applications. Six out of the eleven forages tested, namely Cynodon dactylon, Pennisetum purpureum cv Mott, Brachiaria decumbens cv Humidicola, Pennisetum purpureum cv Taiwan, Brachiaria decumbens cv Mulato, and Paspalum atratum were recommended based on their high adaptability and significantly higher fresh biomass production (varying from 16.5 to 24.7 ton ha−1 season-1). Findings from this study provide alternatives for forage production systems to support livestock establishment. Soil mineralogy provides important information on nutrient reserves and should be considered part of an integral soil characterization including physical and chemical properties, and heavy metal contents of post-tin mining sites to ensure successful reclamation.

Carcass and meat quality in lambs receiving natural tannins from Mimosa tenuiflora hay

Abstract This study evaluated the level of natural tannins from Mimosa tenuiflora hay replacing Brachiaria decumbens cv. Basilisk hay in the diet of lambs on the composition of the carcass tissue, physicochemical properties, fatty acid profile and sensory attributes of lamb meat. A total of 28 uncastrated Santa Ines lambs with initial average body weight (BW) of 28.0 ± 0.5 kg was distributed in a block randomized design with four treatments each [four levels of inclusion of M. tenuiflora hay, providing four different level of tannins at 1.21 (control or without M. tenuiflora hay), 9.3; 17.4 and 25.4 g/kg dry matter (DM) total] and seven replicates. The inclusion of natural tannins from M. tenuiflora hay in the lamb diet resulted in quadratic increases (P

Evaluación de fibra detergente neutra indigestible con incubación en diferentes especies

Objetivo do presente estudo foi avaliar a concentração da fibra em detergente neutro indigestível (FDNi) após a incubação ruminal em bovinos, caprinos e ovinos, e comparar os diferentes resultados com os métodos de estimativa e relacionar os dados com as análises químicas. Quatros forragens (silagem de milho, cana-de-açúcar, Brachiaria decumbens cv. Marandu e Panicum maximum cv. Tanzânia) dois concentrados (milho em grão e farelo de soja), um subproduto (casquinha de soja) e três amostras de fezes (bovino, caprino e ovino) foram incubadas em novilhos Nelore, cabras Saanen e ovinos Santa Inês. Os animais foram previamente adaptados a dieta experimental por 8 dias e incubação ocorreu por 240 horas. A concentração de FDNi foi mais alta nas amostras incubadas no rúmen de caprinos comparada com amostras incubadas no rúmen de bovinos. A incubação nos ovinos aumentou a concentração de FDNi nas forragens e tendeu a aumentar no concentrado e subproduto em relação a incubação no rúmen de bovinos. A concentração de FDNi foi similar para incubação em ovinos e caprinos. Em adição, as fezes bovinas tiveram alta concentração de FDNi, e as fezes de caprinos tiveram menor concentração de FDNi em relação às fezes de ovinos. O modelo CNCPS subestimou a concentração de FDNi nas amostras. Estimativas da FDN não degradável por Conrad et al. (1984) subestimou a concentração de FDNi na cana-de-açúcar e superestimou a concentração de FDNi no P.maximume concentrados. Em geral, a concentração de lignina foi ocomponente das amostrasmais relacionado com a concentração de FDNi. FDA foi a melhor para forragens (R2 = 0.668) e FDN foi melhor para concentrados (R2 = 0.454). Em conclusão, os processos digestivos das diferentes espécies afetam a concentração de FDNi do alimento. Erros nas estimativas dos modelos foram consideráveis e as características dos alimentos afetam a composição química e concentração de FDNi.

Tropical Forage Grasses Intercropped Under Lenient Grazing Intensities Promote Greater Soil Cover

The diversity of grasses in the intercropping promotes greater soil cover regardless of the grazing intensity used. The aim was evaluated how cultivation systems (monoculture and intercropped) influence the proportion of soil discovered under different grazing intensities. The experiment was conducted at the premises of the Brazilian Agricultural Research Company. The pastures were combined two cultivation systems: monoculture of Panicum maximum cv. BRS Zuri; intercropping of Panicum maximum cv. BRS Zuri, Brachiaria brizantha cv. Xaraes and Brachiaria decumbens cv. Basilisk. Four evaluation cycles were performed, which totaled in 2136 observations. In the contrast between evaluation cycles, it is possible to infer that cycles II, III and IV have a negative effect in relation to cycle I, because after the first evaluation there is an increase in the proportion of soil discovered in the pastures studied. In relation to cultivation systems, the intercropped managed at high grazing intensities impacts negative effects, and it is possible to observe the highest values of uncovered soil, as well as the lowest tussock distribution values. The intercropping of tropical climate pastures has greater soil cover when managed in lenient grazing intensity.

Plant growth regulator and soil fertilizer improve production and growing stage of Brachiaria decumbens

AbstractIt is necessary to increase the rates of initial growth of pastures for use during the better planting period. Thus, two experiments were used to evaluate the effect of plant growth regulator (PGR; auxins, gibberellins and cytokinins) in seeds types (coated with polymer coating fungicide and conventional method) and nitrogen fertilization methods in Brachiaria decumbens cv. Basilisk on the germination, growth, development and physiological composition. From the regression estimates, lower levels of PGR (10.3; 12.8; 8.85 and 9.57 ml/kg for germination percentage, germination speed index, leaf and pseudostem, respectively) were recommended in coated seeds when compared to conventional method (untreated seeds, with polymer coating and fungicide). Leaf and pseudostem mass production had a significant interaction effect between seed type and the use of growth regulator. Coated seeds (with fungicide and polymers after scarification) had greater performance with absence or at lower levels (8.85 and 9.57 ml/kg seed) of growth regulators. This was not observed for conventional seeds, the higher doses (15.5 and 18.1 ml/kg) presented higher development for the same characteristics. In second experiment, rates of photoassimilate were increased by soil fertilization and use of PGRs. No influence of foliar fertilization was observed when used exclusively, but N‐fertilization multiple and soil promotes an increase in chlorophyll content and mass yield, respectively. The use of exogenous hormonal compounds acts on the organogenesis of plant tissues and increases the formation of plant tissues and acts in the promotion of germination and development of structures, making it a key tool in pasture establishment.

Olfactory response of Mahanarva spectabilis (Hemiptera: Cercopidae) to volatile organic compounds from forage grasses

Several herbivorous insects utilize plant chemical cues to identify hosts for feeding. The role of smell in host plant detection by Mahanarva spectabilis (Distant) remains largely unknown. In this study, assays were applied to assess M. spectabilis olfactory responses to forage grasses (Pennisetum purpureum cvs. Roxo Botucatu and Pioneiro; Panicum maximum cvs. Makueni and Tanzânia; Hyparrhenia rufa cv. Jaraguá; Melinis minutiflora; Cynodon dactylon cv. Tifton; Brachiaria brizantha cv. Marandú; and Brachiaria decumbens cv. Basilisk). Bioassays were performed using a Y-olfactometer to evaluate the behavior of adult M. spectabilis to forage damaged and undamaged by insects. M. spectabilis preferred volatiles of undamaged Basilisk and Pioneiro. Repellent behavior by M. spectabilis to cospecifics was recorded for plant volatiles from damaged Marandú. The mixture of volatiles from undamaged forage grasses differed from that of forage grasses damaged by insects. Forage grasses showed a greater diversity of compounds after damage, including menthone, eucalyptol and camphor, which are compounds likely to cause loss of attractiveness or repellence. Our results demonstrate that M. spectabilis employs plant chemical cues in its choice of hosts. This fact may contribute to strategies of integrated management against this pest.

Evaluation of a long-established silvopastoral Brachiaria decumbens system: plant characteristics and feeding value for cattle

One of the main challenges of using a silvopastoral system (SPS) is maintaining pasture and animal productivity over time. Our objective was to compare the productive characteristics and nutritive value of signal grass (Brachiaria decumbens cv. Basilisk) and the liveweight gain of dairy heifers in a SPS and open pasture (OP, signal grass under full sunlight) during the rainy seasons of four experiments between 2003 and 2016, which characterised systems from their 6th to 19th years after establishment in south-eastern Brazil when analysed together. The experimental design was a randomised complete block in a 2 × 4 factorial scheme (two production systems (SPS and OP) and four experiments (2003–2004, 2004–2007, 2011–2014 and 2014–2016)). From the 7th year onwards, the progressive reduction of photosynthetically active radiation negatively impacted the productive characteristics of the SPS pasture. Total forage mass was reduced by 19% in SPS compared with the OP in 2004–2007, 38% in 2011–2014 and 31% in 2014–2016. Crude protein content was 23% and 30% higher in the SPS than in the OP in 2011–2014 and 2014–2016, respectively. However, during the study period (until the 19th year), the liveweight gain of heifers was similar between systems since the higher crude protein content available in SPS contributed to improved forage nutritional value. From the 17th to the 19th year, weight gain per area was lower in the SPS compared with the OP (169 vs 199 kg ha–1), although the difference between systems was small. Signal grass presents a high degree of phenotypic plasticity in response to changes in shade levels, which gives this species a high potential for use in SPS.

Multivariate analysis and vigor tests to determine the quality of Brachiaria decumbens seeds

This study aimed to verify the efficiency of multivariate analysis in the identification of promising vigor tests for the evaluation of the physiological quality of seed lots of Brachiaria decumbens cv. Basilisk. Seeds of B. decumbens cv. Basilisk were tested for the following parameters: water content, germination, first germination count, cold test, electrical conductivity, seedling growth, seedling dry mass, first count and emergence percentage of seedlings in laboratory substrate, and seedling emergence in the field. The data obtained in each test—all completely randomized experimental designs—were analyzed separately by means of analysis of variance, Scott-Knott’s test, and multivariate analysis. Principal component analysis is efficient to discriminate vigor and seed germination tests capable of identifying the top performance batch in the field. Germination, first germination count, emergence of seedlings in sand, first seedling emergence count in sand, shoot length, and the cold test are promising in the evaluation of the physiological quality of seed lots of B. decumbens cv. Basilisk, providing similar information to that from the emergence of field seedlings.

Divergência nutricional de clones de Brachiaria ruziziensis

ABSTRACT: The aim of this study was to evaluate the nutritional diversity of Brachiaria ruziziensis clones through chemical composition and in vitro kinetics of ruminal fermentation. Twenty three clones of Brachiaria ruziziensis were used (15, 16, 46, 174, 411, 590, 651, 670, 768, 776, 844, 859, 950, 965, 970, 975, 1067, 1093, 1296, 1765, 1806, 1894 and 1972) and Brachiaria ruziziensis cv. ‘Kennedy’, Brachiaria brizantha cv. ‘Marandu’ and Brachiaria decumbens cv. ‘Basilisk’ as controls within 27 days of harvesting. The experimental design used randomized blocks with 26 treatments (genotypes) and three replications. Evaluation of the nutritional divergence was performed using principal components analysis, based on the following discriminatory variables: in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF), lignin, crude protein (CP), degradation rate of non-fibrous carbohydrates (KdNFC) and degradation rate of fibrous carbohydrates (KdFC). The evaluation of the nutritional diversity of Brachiaria genotypes was based on the two main components (IVDMD and NDF), which explains 96.2% of the total variance Variables of lower contribution to the discrimination of the clones were as degradation rates of the fibrous and non-fibrous carbohydrates. In the agglomerative hierarchical grouping analysis, five distinct groups were identified, where V group, formed by clones 46, 768 and 1067 have higher values of IVDMD compared to the other clones.

Morphological adaptations of signal grass in response to liming and cutting severities

Changes in morphological composition and in the plant population were evaluated during late spring, summer and autumn, in swards of Brachiaria decumbens cv. Basilisk in response to liming (C0.0, without liming; C0.7, limestone amount equivalent to 0.7 ton ha-1; and C1.0, limestone amount equivalent to 1.0 ton ha-1), which were subjected to severe or lenient cutting (40 or 60% of the pre-cutting height, respectively). Increased limestone doses did not result in higher herbage mass (HM), leaf area index (LAI) or proportion of leaves (%L) in the pre-harvest. However, lower proportion of dead material was registered in C0.7 treatment. The treatments C0.0 e C0.7 had higher %L during late spring and summer when associated to severe cutting regimes (R40%), although they reached the pre-harvest condition with lower HM and longer regrowth periods compared to lenient cuttings. The Brachiaria decumbens cv. Basilisk modifies its shoot architecture during the growth season, indicating that lower pre-harvest heights are required during autumn. The absence of liming led to a sharp decreasing of base saturation and levels of K, Ca and Mg in the soil. The minimum annual amount of limestone required for B. decumbens correspond to 0.7 ton ha-1.

Evaluation of forage grass resistance to Mahanarva fimbriolata (Stål)

ABSTRACT The aim of this study was to select forage grasses with potential resistance to Mahanarva fimbriolata by assessing effects on insect. No-choice assays were conducted with 12 genotypes and laboratory-reared insects. The following parameters were assessed: mortality and duration of the nymphal stage; adult weight and longevity; pre-oviposition period; number of eggs/female; viability and duration of the embryonic period. As main result it was verified that the mortality of nymphs reared on Panicum maximum cv. Paredao is almost complete and that this forage grass may be characterized as resistant to this insect by antibiosis. Further, the grasses can be divided into three groups following a cluster analysis: P. maximum cv. Aries, Setaria sphacelata cv. Kazungula, Brachiaria humidicola, A. gayanus and P. maximum cv. Aruana, which are insect-resistant grasses; Brachiaria decumbens cv. Basilisk, B. dictyoneura, B. brizantha cv. MG-4 and B. ruziziensis, which are moderately resistant grasses; and B. brizantha MG-5 and B. brizantha ecotype BB185, which are susceptible grasses.

De novo RNA sequencing and analysis of the transcriptome of signalgrass (Urochloa decumbens) roots exposed to aluminum

Acidic soils occupy a vast area in the world, and the aluminum (Al) in these soils can directly interact with plant cells and tissues to inhibit their growth and reduce yields. The signalgrass Urochloa decumbens cv. Basilisk (syn. Brachiaria decumbens cv. Basilisk), a widely sown tropical forage grass, is recognized for its high productivity under intensive use, vigorous growth, ease of establishment, and good forage value throughout the year, as well as its exceptional adaptation to infertile acid soils. We sequenced the transcriptome from roots of U. decumbens cv. Basilisk under two conditions, with and without Al, using Illumina paired-end sequencing technology and performed de novo assembly of those reads, which yielded 164,920 transcripts. Of these transcripts, 113,918 were assigned a putative protein function through comparisons with different gene set databases. Additionally, 13,375 simple sequence repeat (SSR) markers were identified. Digital gene expression analyses were conducted to identify 6698 differentially expressed genes between treatments, revealing a great differences in the root transcriptional landscape when exposed to aluminum. An extensive annotation of the differentially expressed genes (DEGs), made possible to identify several transcripts with putative functions correlated to aluminum exposure, most belonging to vesicle transportation, cell wall modifications and metal handling ontologies. In this work, abundant, high-quality transcripts were obtained, providing a reference platform for future biotechnological studies and breeding programs for this species and its close relatives.

English

The objective of this work was to evaluate the use of ten types of grasses as base substrate for the cultivation of strain GLM-10/02 of Ganoderma lucidum, considering the chemical characterization of the substrates, the biological efficiency (BE), the quantification of fresh and dry basidiomata and the number of basidiomata as evaluation criteria. Ten treatments were outlined, made up with napier or elephant grass (Pennisetum purpureum), marandu grass (Brachiaria brizantha cv. Marandu), aruana grass (Panicum maximum cv. Aruana), massai grass (Panicum maximum cv. Massai), mombaca grass (Panicum maximum cv. Mombaca), brachiaria grass (Brachiaria decumbens cv. Basilisk), humidicola (Brachiaria humidicola cv. humidicola), xaraes grass (B. brizantha cv. Xaraes), tifton (Cynodon species cv. Tifton 85), piata grass (B. brizantha cv. BRS Piata) and a control treatment based on eucalyptus sawdust. All the treatments had 80% of grass, 18% of wheat bran and 2% of limestone, with humidity adjusted to 60%. The treatments based on B. brizantha cv. Aruana (aruana) and Cynodon spp. cv. Tifton 85 (tifton) showed the best results, with 22.9 and 25% of BE, respectively. These data showed that not all grasses used in the experiment have the same fungal biomass conversion and it was concluded that B. brizantha cv. Aruana (aruana) and Cynodon spp. cv. tifton 85 (tifton) were the most indicated grasses for the cultivation of G. lucidum. Key words: Productivity, biological efficiency, substrates, fungi.

Temporal differences in plant growth and root exudation of two Brachiaria grasses in response to low phosphorus supply

Exploiting the natural variability of Brachiaria forage germplasm to identify forage grasses adapted to infertile acid soils that contain very low available phosphorus (P) is an important research objective for improving livestock production in the tropics. The objective of this study was to determine the differences in the release of root biochemical markers, i.e. carboxylates and acid phosphatases (APases), during the development of P deficiency in signalgrass and ruzigrass. We used the hydroxyapatite pouch system in hydroponics to simulate conditions of low P supply in acid soils to test the response of well-adapted signalgrass ( Brachiaria decumbens cv. Basilisk, CIAT 606) and less-adapted ruzigrass ( B. ruziziensis cv. Kennedy, CIAT 654). We monitored shoot and root growth and other physiological and biochemical components that are important for root functionality at weekly intervals for 3 weeks. We found that monocarboxylate exudation was not associated with the plant’s physiological P status, while exudation of oxalate and secreted-APases increased with declining plant P concentrations in both grasses. Ruzigrass showed higher exudation rates and grew faster than signalgrass, but could not maintain its initial fast growth rate when P concentrations in plant tissue declined to 1.0 mg P/g dry matter. Oxalate was the dominant exuded carboxylate for signalgrass after 21 days of growth and this response might confer some eco-physiological advantages in signalgrass when grown in low-P acid soils.

Herbage accumulation, plant-part composition and nutritive value on grazed signal grass (Brachiaria decumbens) pastures in response to stubble height and rest period based on canopy light interception

Signal grass (Brachiaria decumbens cv. Basilisk, syn. Urochloa decumbens Stapf R.D. Webster) has been widely grown in the Brazilian tropics over the last 40 years, but management recommendations have been largely empirical and not based on canopy targets. This study was designed to characterise and explain the impact of canopy-based grazing strategies on herbage accumulation, plant-part composition, and nutritive value of signal grass. Treatments were factorial combinations of two stubble heights, 5 cm (SH5) and 10 cm (SH10), and two grazing frequencies, grazing initiated when 95% (LI95) and 100% (LI100) of incoming light was intercepted by the canopy. Rest periods were imposed during summer and autumn of both experimental years. Leaf blade accumulation was greater for LI100 than LI95 (9.5 v. 8.8 t/ha) associated with increased stem accumulation (4.6 v. 3.5 t/ha for LI100 v. LI95). The SH10 pastures produced more stem than SH5 pastures (4.4 v. 3.6 t/ha), with no difference in leaf blade accumulation. In general, SH10 pastures had more residual leaf blade mass post-graze, whereas SH5 pastures combined with higher grazing frequency (SH5-LI95) became more prostrate over time, increasing leaf blade proportion in post-graze forage. Over time, stubble height had more influence than grazing frequency on leaf blade proportion at pre-graze, and SH5 pastures had leafier canopies than SH10 pastures. Digestibility was less under LI100, especially when associated with SH5 stubble (SH5-LI100), regardless of season of the year. To provide optimal leaf blade yield and overall forage digestibility, particularly during warm, rainy seasons, defoliation of signal grass should include pre-graze height varying from 18 to 30 cm (95–100% of light interception) and mean stubble height close to 10 cm.

Ingestive behavior of heifers on Brachiaria pasture deferred with different periods of sealing

This study aimed to evaluate four deferral periods for pastures of Brachiaria decumbens cv. Basilisk, and the implications on the ingestive behavior of crossbred heifers. Animals were distributed in a completely randomized design with four periods (63, 84, 105 and 126 days), each with three replications. The time spent daily by animals on grazing, idle, rumination and in the trough was not affected by periods of sealing the pastures, with mean values of 566.6; 422.29; 426.9 and 24.1 minutes, respectively. The number of feeding stations, the time spent in the stations and the number of feeding stations per minute were not different between periods of sealing the pastures, averaging 106.4; 34.6 and 3.0, respectively. The number of bites and the number of bites per minute showed a quadratic effect, with a point of maximum equal to 1,098 bites and 31 bites per minute, observed on days 93 and 88, respectively. Feed efficiency was linearly decreasing influenced by periods of sealing the pastures. Periods of grazing and idle, the number of bites, the number of bites per minute and feed efficiency are influenced by different deferral periods of pastures under the conditions of this study.

Seletividade aparente de bovinos em pastos de capim-braquiária sob períodos de diferimento

RESUMO Objetivou-se compreender o efeito do período de diferimento sobre a seletividade aparente de bovinos pelos componentes morfológicos e de valor nutritivo do pasto de Brachiaria decumbens cv. Basilisk. Adotaram-se o esquema de parcela subdividida e o delineamento em blocos ao acaso com duas repetições. Foram estudados quatro períodos de diferimento (73, 103, 131 e 163 dias) e duas amostras de forragem (disponível na pastagem (DP) e obtida pela simulação de pastejo (SP)). As percentagens de lâmina foliar viva (LFV), matéria seca potencialmente digestível (MSPD) e proteína bruta (PB) foram maiores na amostra de SP, quando esta foi comparada à forragem DP. Padrão de resposta contrário ocorreu com os percentuais de colmo vivo (CV), colmo morto (CM) e fibra em detergente neutro (FDN). De modo geral, o maior período de diferimento resultou em pior composição morfológica e valor nutritivo das forragens. Os índices de seletividade aparente (ISA) da LFV, do CV e da lâmina foliar morta (LFM) aumentaram linearmente com o período de diferimento. O ISA do CM apresentou maiores valores em pastos sob períodos intermediários de diferimento. Com o aumento do período de diferimento, os ISA da FDN e da MSPD permaneceram constantes, os ISP da FDN potencialmente digestível e da PB reduziram linearmente, e o ISP da FDN indigestível incrementou de maneira linear. O ISA permite a compreensão da seletividade dos componentes morfológicos e das entidades nutricionais do pasto pelos bovinos. A redução do período de diferimento melhora a estrutura do pasto e otimiza a seletividade dos bovinos.

Using swine farming wastewater for Signal grass cultivation

The objective of this study was to evaluate forage production and root accumulation in Brachiaria decumbens cv. Basilisk with swine wastewater as a fertilizer. The experiment was conducted into a greenhouse in Federal Institute of Education, Science and Technology of Southeast of Minas Gerais, Rio Pomba Campus. Pots with 6 dm-3 volumes were used as experimental units. Were used a randomized block design with four replications. Were studied four swine waste doses (0, 225, 450 and 675mL pot-1) over four regrowth cycles. The dry matter production of the aerial part, forage accumulation rate, crude protein and dry matter production of roots increased with the highest swine waste doses being around 670, 742, 160 and 465% respectively from lower to higher dose. There was interaction between swine waste and regrowth cycles for plant height and tillering, and in all regrowth cycles responded positively with increasing swine waste doses. Applying swine waste on pastures is therefore a viable alternative to increase productivity of B. decumbens cv. Basilisk, it recommends the use of swine waste corresponding to the dose of 675mL pot-1 to maintenance pastures