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Gamba grass (Andropogon gayanus Kunth) is a tussock-forming forage species adapted to acid soils of Brazilian savannas and cultivated for grazing pastures. Four decades since its release, Planaltina prevails as the most commercialized cultivar of the species, even though the new cultivar BRS Sarandi could be a better alternative for Gamba-grass-based farms by presenting a greater leaf:stem ratio. The objective of this study was to evaluate the average daily live weight gain (ADG) of Nellore bulls (Bos indicus) for two Gamba grass cultivars—Planaltina and Sarandi. The experiment was conducted in Planaltina, Federal District, Brazil, for 3 years, namely 2018, 2018–2019, and 2020. The experimental design was a completely randomized block design with two treatments and three replicates, each one continuously stocked at three stocking rates (SR)—1.3, 2.6, and 4 young bulls/ha. Canopy height (CH), forage mass (FM), plant-part proportion (green leaf, stem, and dead material), and nutritive value were evaluated. In 2018, mean ADG for Sarandi pastures was greater (0.690 kg/bull/d) than that of Planaltina (0.490 kg/bull/d) (p < 0.10). In the subsequent year (2018–2019), there was no effect of cultivar (p > 0.10), while in 2020 the ADG was again affected by cultivar (p < 0.10), confirming the advantage of Sarandi (0.790 kg/bull/d) over Planaltina (0.650 kg/bull/d). In 2018 and 2020, the percentage of stems for Sarandi was about 3–6 pp less than for Planaltina (p < 0.10). As well as for stems, Sarandi pastures presented a shorter CH in 2028 and 2020 (6–7%) (p < 0.10). The positive high correlation of leaf:stem ratio with ADG (r = 0.70) probably predisposed the superiority of Sarandi over Planaltina. The distinguishing plant-part composition of Sarandi canopy promotes increasing weight gain of beef cattle when compared to cv. Planaltina. [ABSTRACT FROM AUTHOR]

Gamba grass (Andropogon gayanus Kunth) is a tussock-forming forage species adapted to acid soils of Brazilian savannas and cultivated for grazing pastures. Four decades since its release, Planaltina prevails as the most commercialized cultivar of the species, even though the new cultivar BRS Sarandi could be a better alternative for Gamba-grass-based farms by presenting a greater leaf:stem ratio. The objective of this study was to evaluate the average daily live weight gain (ADG) of Nellore bulls (Bos indicus) for two Gamba grass cultivars—Planaltina and Sarandi. The experiment was conducted in Planaltina, Federal District, Brazil, for 3 years, namely 2018, 2018–2019, and 2020. The experimental design was a completely randomized block design with two treatments and three replicates, each one continuously stocked at three stocking rates (SR)—1.3, 2.6, and 4 young bulls/ha. Canopy height (CH), forage mass (FM), plant-part proportion (green leaf, stem, and dead material), and nutritive value were evaluated. In 2018, mean ADG for Sarandi pastures was greater (0.690 kg/bull/d) than that of Planaltina (0.490 kg/bull/d) (p < 0.10). In the subsequent year (2018–2019), there was no effect of cultivar (p > 0.10), while in 2020 the ADG was again affected by cultivar (p < 0.10), confirming the advantage of Sarandi (0.790 kg/bull/d) over Planaltina (0.650 kg/bull/d). In 2018 and 2020, the percentage of stems for Sarandi was about 3–6 pp less than for Planaltina (p < 0.10). As well as for stems, Sarandi pastures presented a shorter CH in 2028 and 2020 (6–7%) (p < 0.10). The positive high correlation of leaf:stem ratio with ADG (r = 0.70) probably predisposed the superiority of Sarandi over Planaltina. The distinguishing plant-part composition of Sarandi canopy promotes increasing weight gain of beef cattle when compared to cv. Planaltina.

Background: Understanding the biomass accumulation and growth rate of the forages to feed the animal throughout the year is critical for improved earnings and long-term livestock production. This was found in forage maize (Zea mays), forage millet (Echinochloa utilis), elephant grass (Pennisetum purpureum) and Gamba grass (Andropogon gayanus). The experiment was place at Federal University Oye Ekiti in Ekiti State, Nigeria, in latitude N 07°48.308, longitude E 005°29.573 and elevation 548.4 meters above sea level, with an annual rainfall of 1778 mm. Methods: Planting four rows in a complete randomized design (CRD with four replications) was used to test the forage crops. Before planting, the soil in the experimental field had 49.96% organic matter and 33.59% after the crops were harvested. During the growth season, Pennisetum purpereum had the maximum plant height and sward height. Result: The Zea mays plant had the maximum leaf breadth (5.44 cm at 8 weeks) and the most leaves. Zea mays had the largest biomass accumulation (BC) of 113.80% after 8 weeks, followed by Andropogon gayanus with 67.15 per cent, Pennisetum purpureum with 56.24 per cent and Echinochloa utilis with 51.63%. Although there were no significant differences p≤0.05 in the crude protein levels of the different species, samples from the latest cuts (8th week) had the greatest crude protein content (11.88% in Andropogon gayanus). Crude protein levels were shown to rise in lockstep with grass growth. Although there was no significant difference between the grass species, the crude fibre content of the three grass species was discovered to vary with the growth phase. The greatest fibre content of 13.58% in Zea mays was reported during the 6th week, which might be attributable to lignin encrustation in grasses that were harvested late. All of the plant samples of crops showed the same irregular pattern in crude fiber, moisture content and fat content, with no significant variance. [ABSTRACT FROM AUTHOR]

The use of silvopastoral systems improves the sustainability of resources, enhancing the efficiency of the production system, with potential to offer local and global ecosystem services. The objective of this study was to evaluate the persistence of Andropogon grass (Andropogon gayanus cv. Planaltina) in nine years of growth and the ingestive behavior of goats under continuous stocking in a silvopastoral system during the rainy season, in comparison to the monoculture. The treatments were two production systems: monoculture (Andropogon grass) and silvopastoral system—SPS (native trees mixed with Andropogon grass). The persistence was evaluated between the years of 2011 and 2019 and, the ingestive behavior was evaluated in the grazing periods of 2019 (March, April, May and June). No effect of the interaction between cultivation systems and years was found on forage dry mass yield (P = 0.17) and leaf/stem ratio (P = 0.21), however, the forage dry mass yield was higher (P < 0.01) in the silvopastoral system. There was effect of interaction on the crude protein content (P < 0.01). In addition, there was effect of the different systems on the NDF content (P < 0.01). There were no significant differences (P > 0.10) for the ingestive behavior variables, except for the bite mass that was higher in the monoculture. Significant differences were found for the bite rate, with a mean value of 17.8 bites/min−1. The DM intake in relation to the body weight was equivalent to 2.86% of the BW. There was no difference in the variation of the mean body weight of the goats between the cultivation systems of Andropogon grass. The Andropogon grass pasture grown in monoculture system and SPS remains perennial for nine years of grazing. Goat grazing in the two cultivation systems of Andropogon grass showed similar performance. [ABSTRACT FROM AUTHOR]

The studies were carried on accessions of the Andropogon gayanus-Andropogon tectorum complex (Poaceae) in southwestern Nigeria to determine the chromosome numbers and meiotic dynamics in the species. This involves meiotic chromosome and pollen studies using standard procedures. Studies on the morphology and meiotic behaviour of collections of A. gayanus (2n = 40) and A. tectorum (2n = 20, 40) have been made. The cytogenetic studies show that the chromosome configuration of A. gayanus is a tetraploid (2n = 40) on a basic chromosome number of 10. A. tectorum occurs as a regular diploid on a chromosome number of 2n = 20 and it is the only species found in Ekiti State. Accession “Kiwani” was found to be a polyploid. A. tectorum with a chromosome number of 2n = 40. This study has also established the stability of the genome of the Andropogon complex. In spite of the occurrence of univalent and multiple associations, meiosis ensures a high percentage of pollen grains. The pollens of accession “Kiwani” (> 35 µm) were generally larger than those of other accessions while the other accessions of both A. gayanus and A. tectorum have modal pollen sizes less than 35 µm, although the A. tectorum accessions were generally smaller. The study concluded that the occurrence of the tetraploid (2n = 40 in accession AT10, “Kiwani” can be attributed to apomixis occurring in a lonely plant.

A study was conducted during 2020 rainy season using structured questionnaires which was administered to 90 respondents to evaluate farmer's preference on uncultivated forage species as rainy season feed for ruminants in semi-arid area of Aliero Local Government, Kebbi State, Nigeria. Data collected were analyzed using simple statistical tools such as frequency counts and percentages. The encountered forage species that served as feeds to ruminants in the study area are; Andropogon gayanus, Digitaria debilis, Eragrostis tremula, Pennisetum pedicellatum, Waltheria indica, Commelina banghalensis, Monechma ciliatum, Chrozopora senegalensis, and Corchorus tridens. The results obtained revealed that majority (73.33%) of farmers served forages in fresh forms and offered the forages as a sole diet (78.89%) to ruminants. Most of the farmers (47.78%) reared more than one ruminant species dominated by cattle, sheep and goat with a flock size of about 1-20 in numbers representing (66.67%). Majority of the respondents (68.89%) obtained pasture species by cut and carry basis and the effects of forages on the ruminants besides feeding revealed different perception existed among the farmers with most of them (38.89%) having the opinion that natural pasture species promotes growth and high market value to their animals. Farmers preferred (15.56%) combinations of species like; Commelina banghalensis Digitaria debilis, and Andropogon gayanus to feed their animals during the rainy season. The results revealed effective utilization of uncultivated forages not only as ruminant feeding but also as a means of livelihood among the farmers in the study area. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the response of Andropogon gayanus Kunth to inoculation with Glomus cubense and Azospirillum brasilense, in the presence of drought stress. Materials and Methods: In an established area of A. gayanus, an establishment cutting was performed after seed harvest and inoculation was done with EcoMic® (Glomus cubense) and INICA-8. The experimental design was a complete randomized block, with seven treatments and eight replicas. The treatments consisted of: EcoMic® immediately after cutting, INICA-8 immediately after cutting, INICA-8 + EcoMic® immediately after cutting, EcoMic® a t c utting+ I NICA-8 (15 d ays), I NICA-8 a t c utting + E coMic® (15 days), absolute control and fertilized control (150 kg N/ha, NH3NO4). The dry weight of the aerial part, stem length, length of the flowering section of the stem, length of the inflorescence, dry weight of the racemes and flowering were evaluated. Variance analysis was performed. Differences among means were determined by Fisher's LSD. Results: Area dry weight was higher (p < 0,0001) in the fertilized control than in all treatments (12 036,1 kg/ha). The EcoMic® (9 612,5 kg/ha), EcoMic®+INICA-8 (8 475,0 kg/ha) and EcoMic® (cutting)+INICA-8 (15 days) treatments were superior to the absolute control (6 822,2 kg/ha), as well as to the other inoculated treatments. The EcoMic®+INICA-8 treatment showed statistical superiority in stem length (189,7 cm), raceme dry weight (0,071 g) and flowering (0,4462 %). EcoMic® (cutting)+INICA-8 (15 days) was higher in inflorescence length (16,39 cm) and in length of the flowering section of the stem (56,08 cm), although the fertilized control did not differ from these treatments. Conclusions: The single application of INICA-8 had no higher effect on any of the studied variables. However, EcoMic®, at the time of cutting, alone or combined with Azospirillum, was determinant in most of the variables. These results prove the importance of the application of EcoMic® in this crop under drought stress conditions, as well as the synergy among the microorganisms that were inoculated, when combined with each other due to a higher effect on the plant. [ABSTRACT FROM AUTHOR]

The study investigated the nutritive composition as well as acceptability of ensiled roughages comprising Andropogon gayanus (AG), maize husk (MH), maize stover (MS) and their mixtures in equal proportion with Tephrosia bracteolata (TB) by West African Dwarf (WAD) sheep. Seven treatment diets were formulated comprising AG: 100% Andropogon gayanus, MH: 100% maize husk, MS: 100% maize stover, TB: 100% Tephrosia bracteolata, AG + TB: 50% Andropogon gayanus + 50% Tephrosia bracteolata, MS + TB: 50% maize husk + 50% Tephrosia bracteolata, MS + TB: 50% maize stover + 50% Tephrosia bracteolata. The experiment was completely randomized in design. Significant variations were observed in the chemical composition of the plant materials before and after ensiling. It was revealed that Tephrosia bracteolata, prior to ensiling, had the highest crude protein (CP) content, lowest crude fibre (CF), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL). Similar trend was observed in the chemical composition of Tephrosia bracteolata after ensiling. Inclusion of Tephrosia bracteolata in the roughages improved their nutritional quality. All the silage treatments presented good physical characteristics. The acceptability of the silage by 12 WAD sheep ranked thus: TB > MS + TB > AG + TB > AG > MS > MH + TB > MH. Silage digestibility was highest (66.60%) in TB, closely followed by MH + TB (62.67%) and least in MS. It was concluded that WAD sheep production could be enhanced by feeding ensiled maize plant residues alone or in combination with Tephrosia bracteolata during the lean season. [ABSTRACT FROM AUTHOR]

The objective of this research was to determine the pasture structure, nutritional value, animal behaviour, intake, and performance of Santa Inês sheep grazing pastures with various mixtures of grass (Andropogon gayanus) and forage legume (Stylosanthes sp. and Calopogonium mucunoides). A randomized block design was adopted with the treatments arranged in a 3 x 2 factorial scheme, with the factors consisting of cropping systems and grazing cycles. Grass in the mixed species pastures had a greater leaf/stem ratio than in the monoculture. Total forage mass was greater in the mixed pastures, which had the highest concentrations of crude protein and total digestible nutrients, the lowest fibre concentration, and the highest in vitro dry matter digestibility. Legumes were grazed with the highest frequency, and biting rate was highest in Andropogon gayanus with Stylosanthes sp. The highest intake (kg/day) was found in the mixed swards and the highest animal weight gain (143 g/day) in the mixed pastures. The pastures of Andropogon gayanus mixed with Stylosanthes sp. and C. mucunoides showed improved forage nutritive value and intake compared with the grass monoculture. [ABSTRACT FROM AUTHOR]

Foliar epidermal studies were carried out on accessions of Andropogon gayanus-Andropogon tectorum complex collected in Southwestern Nigeria with a view to providing additional characters of the two species of Andropogon to enhance the understanding of the taxonomic relationship between the two species. The epidermal preparation of the adaxial and abaxial surfaces of the leaf blade was made from the median part of well-matured leaf samples by the scrapping method. The analysis of both qualitative and quantitative characters revealed that study revealed that the costal zones of both adaxial and abaxial surfaces of all accessions studied showed similar features with little or no variation in their expression; epidermal cells are mostly rectangular with wavy walls, and the stomata encountered are paracytic. There was a unique occurrence of cluster of cells at the base of the macro hairs present in A. gayanus which is a diagnostic feature for its accessions collected. Kiwani, an unidentified polyploid accession, has the highest number of bands, the stomata are bigger, which is consistent with gigas effect occasioned by its polyploidy status. Glandular trichomes were present in both diploid and tetraploid of A. tectorum, a diagnostic feature for the species.

The objective of this study was to evaluate the production and chemical composition of three forage species at different regrowth intervals. A 3 x 4 randomized-block factorial design with three forage species (Andropogon, Buffel, and Massai) and four regrowth intervals (21, 35, 49, and 63 days) was used. There was no interaction (p > 0.05) between forage species and regrowth interval on any of the chemical components evaluated. The crude protein content decreased but the contents of neutral detergent fiber, acid detergent fiber and hemicellulose increased with increasing regrowth interval (p > 0.05). Only the contents of crude protein and ether extract were similar (p > 0.05) among grasses. A significant interaction was observed (p < 0.05) between forage species and regrowth interval on forage mass. Andropogon grass had the highest forage mass at 63 days (3,270.1 kg ha-1 DM cut-1) and the highest productivity regardless of the regrowth interval (19.1 t ha-1 DM year-1). Therefore, Andropogon grass was the most productive forage among the tested species. Pastures should be managed with shorter growth intervals due to the highest crude protein level and the lowest contents of neutral detergent fiber and acid detergent fiber.

Foliar epidermal studies were carried out on accessions of Andropogon gayanus-Andropogon tectorum complex collected in Southwestern Nigeria with a view to providing additional characters of the two species of Andropogon to enhance the understanding of the taxonomic relationship between the two species. The epidermal preparation of the adaxial and abaxial surfaces of the leaf blade was made from the median part of well-matured leaf samples by the scrapping method. The analysis of both qualitative and quantitative characters revealed that study revealed that the costal zones of both adaxial and abaxial surfaces of all accessions studied showed similar features with little or no variation in their expression; epidermal cells are mostly rectangular with wavy walls, and the stomata encountered are paracytic. There was a unique occurrence of cluster of cells at the base of the macro hairs present in A. gayanus which is a diagnostic feature for its accessions collected. Kiwani, an unidentified polyploid accession, has the highest number of bands, the stomata are bigger, which is consistent with gigas effect occasioned by its polyploidy status. Glandular trichomes were present in both diploid and tetraploid of A. tectorum, a diagnostic feature for the species. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the characteristics of the pasture and the behavior of grazing goats under continuous stocking in a silvopastoral system (SPS) of Andropogon grass (Andropogon gayanus Kunth cv. Planaltina) in comparison to its monoculture (MC). The treatments consisted of two cropping systems: monoculture of Andropogon grass and silvopastoral system—SPS of native trees mixed with Andropogon grass, evaluated in five grazing periods using goats (February, March, April, May and June). Pasture height, leaf/stem ratio and the dry mass of forage, leaf, stem and dead material were evaluated. The grazing behavior of the goats was also assessed. Significant effect of interaction was observed (p < 0.05) on pasture height and on the dead material dry mass yield of the pasture among cropping systems and grazing periods. There was a significant effect of the different systems (p < 0.05) on the yield of forage dry matter, leaf dry matter and leaf/stem ratio. The SPS presented superior grazing time (p = 0.01), with an average of 389.0 min. Regarding rumination and moving times, there was no difference between cropping systems and grazing periods (p > 0.05). The Andropogon grass has the potential to be used in SPS with grazing goats under continuous stocking, positively affecting the pasture and animal behavior. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the morphogenetic and structural characteristics of tropical grasses managed under different regrowth periods. The experiment was conducted at the Federal Institute of Science and Technology Education of Rio Grande do Norte, located in the municipality of Apodi-RN, Brazil. The study design was in randomized blocks and the treatments were allocated in a 3x4 factorial arrangement, with three cultivars (Andropogon, Buffel and Massai) in four regrowth periods (21, 35, 49 and 63 days). The interaction between cultivar and age was significant for all studied variables, with the exception of leaf blade width and accumulation rate. The highest leaf appearance rates were observed in Buffel grass, regardless of the regrowth age. This characteristic was not influenced by age only in Andropogon grass. Higher stem elongation rates were observed in Buffel grass, while the lowest were observed in Massai grass until 35 days of regrowth, attributed to the presence of inflorescences. Canopy heights in Massai and Andropogon grass were greater than Buffel grass until 35 days of regrowth, Andropogon grass had higher height from 35 days of regrowth than the others. Andropogon grass showed higher rates of accumulation than Massai grass only at 21 days of regrowth, and no effects of regrowth age were observed for this variable. Buffel grass should be defoliated at 21 days, while Andropogon and Massai grass can be managed without losses between 21 and 63 days of regrowth.

A major challenge in sorghum intercropping systems is maintaining their yields compared to the yields of the solo crops, especially in arid and semi-arid regions. This study aimed to test the hypothesis that intercropping systems using sorghum (Sorghum bicolor (L.) Moench.) and Brachiaria sp. are viable means to increase sorghum production and soil carbon in the conservation systems. Field trials were conducted in the semi-arid region of Minas Gerais, Brazil, during two crop cycles of sorghum associated with different grasses (Andropogon gayanus—AG; Cenchrus ciliaris cv. Aridus—CCA; Cenchrus ciliaris cv. 131—CC; Brachiaria decumbents—BD; Brachiaria brizantha—BB; Brachiaria ruziziensis—BR; Panicum maximum—PM), using row spacings of 0.4 and 0.8 m. Panicles of sorghum (yield) and grass dry matter were collected to determine yields. Results showed that the addition of grasses in systems decreased the grain yield in all systems, except in the systems using sorghum with CCA in 0.4 m, AG in 0.8 m, or BR in 0.8 m. In the 0.4 m row spacing, the sorghum associations with CC, BB, or PM are greater alternatives to increase soil carbon. However, when the row spacing was increased, the sole sorghum was the best alternative to increase the carbon. In machine learning, sorghum systems with CCA and AG are better alternatives to increase the yields, while sorghum with CC, PM, BR, and BB increases the grass dry matter in soil.

Os gastos envolvidos no controle do carrapato dos bovinos, no Brasil, giram em torno de US$ 1 bilhão por ano. Uma estratégia de controle de baixo custo é a utilização de forrageiras com propriedades antibióticas e antixenóticas, que integrada a outras medidas pode potencializar o controle. Espécies como Melinis minutiflora, Andropogon gayanus e Stylosanthes spp. têm mostrado eficiência no controle deste parasita. O texto discute algumas propriedades e a aplicabilidade destas espécies.

The objective of this study was to evaluate the production and chemical composition of three forage species at different regrowth intervals. A 3 x 4 randomized-block factorial design with three forage species (Andropogon, Buffel, and Massai) and four regrowth intervals (21, 35, 49, and 63 days) was used. There was no interaction (p > 0.05) between forage species and regrowth interval on any of the chemical components evaluated. The crude protein content decreased but the contents of neutral detergent fiber, acid detergent fiber and hemicellulose increased with increasing regrowth interval (p > 0.05). Only the contents of crude protein and ether extract were similar (p > 0.05) among grasses. A significant interaction was observed (p < 0.05) between forage species and regrowth interval on forage mass. Andropogon grass had the highest forage mass at 63 days (3,270.1 kg ha-1 DM cut-1) and the highest productivity regardless of the regrowth interval (19.1 t ha-1 DM year-1). Therefore, Andropogon grass was the most productive forage among the tested species. Pastures should be managed with shorter growth intervals due to the highest crude protein level and the lowest contents of neutral detergent fiber and acid detergent fiber. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental 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.)

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Avaliou-se a composição química e a cinética de fermentação ruminal de quatro espécies forrageiras submetidas ou não à irrigação. As espécies avaliadas foram Urochloa brizantha cv. MG5 (MG-5), Andropogon gayanus (Andropogon), Urochloa humidicola (Humidicola) e Digitaria umfolozi (Digitaria umfolozi). O experimento foi conduzido na fazenda experimental Campus Rural, São Cristóvão, SE. Observou-se diferença significativa (P

Copyright of Revista Brasileira de Saúde e Produção Animal (RBSPA) is the property of Revista Brasileira de Saude e Producao Animal (RBSPA) 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.)

Grasses are amongst the most abundant and environmentally damaging invasive weeds worldwide. Biological control is frequently employed as a sustainable and cost-effective management strategy for many weeds. However, grasses have not been actively pursued as targets for classical weed biological control due to a perceived lack of sufficiently specialised and damaging natural enemies to use as biological control agents. There are also concerns that the risk posed to economically important crop/pasture species and closely-related native species is too great to consider implementing biological control for invasive grasses. In this paper, we review the literature and demonstrate that grasses can possess suitably host-specific and damaging natural enemies to warrant consideration as potential biological control agents. The risk of grass biological control is no greater than for other weedy taxa if practitioners follow appropriately rigorous risk assessments protocols. [ABSTRACT FROM AUTHOR]

Cow–calf operations constitute the main land-use system in the 18 million ha of well drained tropical savannas of Colombia located in the Orinoco basin. There, numerous sex and age animal categories are present, ranging from suckling calves to old cull cows and steers, which in variable proportions are stocked at one animal unit (AU)/5–10 ha, depending on the ranch and distance from markets. In parallel, early-on farm observations showed that when sown pastures are introduced, graziers recur to opportunistic partial fattening of cull animals for a rapid economic return. The paper reports animal weight gains of cull cows, old steers, and young heifers and yearlings over seven consecutive years grazing on a low fertiliser-input well managed Andropogon gayanus -based pasture and four contemporary years on Brachiaria humidicola. The first 2 years involved three stocking rates (SR; 1.38, 1.85 and 2.32 animal units/ha), whereas a single SR of 1.33 animal units/ha was used for the remainder. A large database that included chemical, and in vitro and in vivo digestibility, values for all forages involved, was used as an input to a mathematical model to estimate methane (CH4) emissions. Estimations were compared with weight-based predictions derived from chamber measurements recorded recently in tropical Australia. Faecal mineral concentration varied little (not significantly) among SR and animal categories. Weight gains of old steers were 4–24% larger than those of cull cows, which, in turn, were larger than those of young steers and heifers (P < 0.01). Excepting one year, the performance of cull cows and old steers did not differ between pastures, confirming earlier on-ranch observations of reasonable weight gains of adult cattle on both pastures. The predicted carcass composition of cull cows and old steers did not differ between pastures either. Over the length of the experiment, cull cows emitted significantly less CH4 than did old steers (129 vs 141 g/day) on A. gayanus , while emissions on B. humidicola amounted to 128 and 137 g/day respectively. Despite between-year differences in animal performance, they are indicative of well managed pasture sustainability. They also show some of the trade-offs involved in the use of contrasting animal categories and pastures in terms of weight performance and predicted carcass composition and CH4 production. The authors expect that the present results will contribute to a rational, science-based discussion of the role of beef systems vis-à-vis environment in a region with limited production alternatives. In a tropical savanna environment, beef systems produce a variety of animal types differing in feed efficiency and meat yield, but the environmental impact of the systems is still limited. Growth on pastures in decreasing order were steers, cull cows, yearlings and heifers. Compared to steers, daily methane emissions were lower in cows, but their emissions per kg of edible protein were slightly higher. Trade-offs between growth, carcass characteristics, and methane emissions faced by the beef industry are illustrated but need further study. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of application of calcium and magnesium silicate on the productivity, chemical composition and in situ ruminal degradation of bluestem grass (Andropogon gayanus Kunth, cv. Baeti; Embrapa 23) during the rainy and dry seasons. The design consisted of completely randomized blocks in a 6x2 factorial scheme (six silicate doses and two cutting seasons), arranged in plots subdivided over time. The plots were the calcium and magnesium silicate doses (0, 200, 400, 600, 800 and 1,000 kg/ha) and the subplots were the two cutting seasons (rainy and dry period), with five repetitions (blocks). The calcium and magnesium silicate doses exerted no significant effect on green or dry matter production, chemical forage composition or degradability parameters. On the other hand, there was an effect of cutting period on forage production and chemical composition. The highest production of green and dry matter was observed during the rainy period, while acid detergent fiber content was higher during the dry season. The treatments did not exert any significant effect on the parameters of degradability that would alter the nutritive value of bluestem grass.

Fire disturbance in tropical savannas is integral to maintaining habitat heterogeneity and biodiversity, but its impact on avian species is highly variable. Savannas in northern Australia have recently been invaded by gamba grass (Andropogon gayanus), a perennial tussock grass that fuels late season fires at eight times the intensity of native vegetation. As gamba grass rapidly outcompetes native species and promotes more frequent and intense fires, it greatly decreases landscape heterogeneity and alters the effect of fire in tropical savannas. To investigate how a small passerine, the red‐backed fairywren (Malurus melanocephalus), responds to fire disturbance and gamba grass cover, we studied their fine‐scale habitat use throughout the dry season before and after a high intensity fire. We used two spatially distinct approaches, radio‐telemetry and a transect‐based population census, to quantify fairywren habitat use at the group and population level, respectively. Radio‐telemetry and transect surveys revealed no direct mortality associated with the severe bushfire during the middle of the study season, suggesting fairywrens are resilient in the short‐term to fire disturbance. Our results indicate that fairywrens are largely flexible in their habitat use – instead of relocating after fire, they re‐centre their home range around the most photosynthetically productive habitats, dominated by saplings. While we found substantial variation in habitat use among social groups, red‐backed fairywren groups generally avoided dense habitat areas dominated by mature gamba grass. We conclude that red‐backed fairywrens are resilient to fire and flexible in their habitat use in the short‐term; however, in the long‐term, gamba grass may pose a threat to population viability. The importance of flexible behavioural strategies in tropical passerines will increase as fire regimes are exacerbated by invasive species and climate change. [ABSTRACT FROM AUTHOR]

In vitro batch cultures were used to screen four fibrolytic enzyme mixtures at two dosages added to a 60 : 40 silage : concentrate diet containing the C4 tropical grass Andropogon gayanus grass ensiled at two maturities – vegetative stage (VS) and flowering stage (FS). Based on these studies, one enzyme mixture was selected to treat the same diets and evaluate its impact on fermentation using an artificial rumen (Rusitec). In vitro batch cultures were conducted as a completely randomized design with two runs, four replicates per run and 12 treatments in a factorial arrangement (four enzyme mixtures×three doses). Enzyme additives (E1, E2, E3 and E4) were commercial products and contained a range of endoglucanase, exoglucanase and xylanase activities. Enzymes were added to the complete diet 2 h before incubation at 0, 2 and 4 μl/g of dry matter (DM). Gas production (GP) was measured after 3, 6, 12, 24 and 48 h of incubation. Disappearance of DM (DMD), NDF (NDFD) and ADF (ADFD) were determined after 24 and 48 h. For all four enzyme mixtures, a dosage effect (P0.05) DM, N, NDF or ADF disappearance after 48 h of incubation nor daily ammonia-N, volatile fatty acids or CH4 production. However, enzyme application increased (P

The biosorption of strontium(II) from aqueous solutions using dead bacteria biomass was investigated in this study. Phylogenetic analysis based on 16S rDNA sequence demonstrates that the isolated strain belonged to Bacillus cereus. The bacteria exhibited the highest strontium sorption capacity at an initial pH of 5.0, contact time of 50 min, biomass dosage of 3.0 g L−1 and agitation speed of 120 rpm. The adsorption profile was better matched by Langmuir than Freundlich model. The maximum biosorption capacity obtained by Langmuir model was 58.79 mg g−1. Adsorption kinetics indicate that the pseudo-second order model was appropriate to describe the biosorption process. Fourier transform infrared (FT-IR) spectroscopy analysis indicates that the main functional groups responsible for biosorption of strontium(II) were hydroxyl, carboxyl and amino. The isolated bacteria B. cereus can be a great potential biosorbent to remove strontium ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

Globally, invasive grasses are a major threat to protected areas (PAs) due to their ability to alter community structure and function, reduce biodiversity, and alter fire regimes. However, there is often a mismatch between the threat posed by invasive grasses and the management response. We document a case study of the spread and management of the ecosystem-transforming invasive grass, Andropogon gayanus Kunth. (gamba grass), in Litchfield National Park; an iconic PA in northern Australia that contains significant natural, cultural and social values. We undertook helicopter-based surveys of A. gayanus across 143,931 ha of Litchfield National Park in 2014 and 2021–2022. We used these data to parametrise a spatially-explicit spread model, interfaced with a management simulation model to predict 10-year patterns of spread, and associated management costs, under three scenarios. Our survey showed that between 2014 and 2021–22 A. gayanus spread by 9463 ha, and 47%. The gross A. gayanus infestation covered 29,713 ha of the total survey area, making it the largest national park infestation in Australia. A. gayanus had not been locally eradicated within the Park's small existing 'gamba grass eradication zone', and instead increased by 206 ha over the 7-year timeframe. Our modelled scenarios predict that without active management A. gayanus will continue spreading, covering 42,388 ha of Litchfield within a decade. Alternative scenarios predict that: (i) eradicating A. gayanus in the small existing eradication zone would likely protect 18% of visitor sites, and cost ∼AU$825,000 over 5 years – more than double the original predicted cost in 2014; or (ii) eradicating A. gayanus in a much larger eradication zone would likely protect 86% of visitor sites and several species of conservation significance, and cost ∼AU$6.6 million over 5 years. Totally eradicating A. gayanus from the Park is no longer viable due to substantial spread since 2014. Our study demonstrates the value of systematic landscape-scale surveys and costed management scenarios to enable assessment and prioritisation of weed management. It also demonstrates the increased environmental and financial costs of delaying invasive grass management, and the serious threat A. gayanus poses to PAs across northern Australia. • Invasive grasses are a growing challenge for protected areas managers worldwide. • Landscape-scale survey is essential to understand invasive grass distribution/spread. • Our survey showed Andropogon gayanus increased by 9463 ha in 7 years, to cover an area of 29,713 ha. • Delaying management action has doubled cost of achieving weed management goals. • Park managers should use systematic surveys and costed scenarios to prioritise weed management. [ABSTRACT FROM AUTHOR]

It was evaluated the effects of different irrigation and nitrogen (N) doses on morphogenesis and structural Andropogon grass (Andropogon gayanus cv. Planaltina). The study was conducted in period from August to December, 2007 in experimental area of EMBRAPA Meio-Norte, located in city of Parnaíba, Piauí, Brazil. The treatments consisted of two irrigation levels (equivalent to replacement of 50% and 80% of the Class A pan evaporation - ECA) and four doses of nitrogen (equivalent to 200, 400, 600 and 800 kg N/ha/year) in a randomized block design in factorial 2 x 4 with three replications. The nitrogen in the form of urea was applied according to the amounts specified in the treatments (16.7, 33.3, 50.0 and 66.7 kg N/cut). The reduction in water depth provided decreases in leaf elongation rate, leaf appearance, final leaf length and number of life leaves, while the rate of senescence increases. Fertilization increased the leaf elongation rate and leaf appearance. However, tended to reduce the number of life of leaves and expand the level senescence. Avaliou-se os efeitos de diferentes lâminas de irrigação e doses de nitrogênio (N) sobre as características morfogênicas e estruturais do capim-andropogon (Andropogon gayanus cv. Planaltina). O estudo foi conduzido no período de agosto a dezembro de 2007, na área experimental da EMBRAPA Meio-Norte, em Parnaíba, Piauí. Os tratamentos consistiram em duas lâminas de irrigação (equivalentes à reposição de 50% e 80% da Evaporação do Tanque Classe A - ECA) e quatro doses de nitrogênio (equivalente a 200, 400, 600 e 800 kg de N/ha/ano), em delineamento em blocos casualizados, e esquema fatorial 2 x 4, com três repetições. A adubação nitrogenada, sob forma de uréia, foi aplicada de acordo com as quantidades estabelecidas nos tratamentos (16,7; 33,3; 50,0 e 66,7 kg de N/corte). A redução da lâmina de irrigação proporcionou decréscimos nas taxas de alongamento da folha, aparecimento de folha, comprimento final da folha e número de folhas vivas, enquanto a taxa de senescência aumentou. A adubação incrementou as taxas de alongamento da folha, aparecimento de folha e comprimento final da folha. No entanto, tendeu a reduzir o número de folhas vivas e a ampliar a taxa de senescência.

The knowledge of interaction between infective larvae setting and the type of grass is important to epidemiological studies and the control of gastrointestinal nematodes in sheep. The objective of this work was to evaluate the effects of three species of forage grasses on pasture characteristics and the vertical distribution of infective larvae (L3) of gastrointestinal nematodes of woolless sheep on the grasses during the rainy season. Sixty non-periparturients ewes were used, naturally infected, equally distributed on 2 ha paddocks sowed with Tanzania, star, and gamba grasses, managed under continuous grazing system, from October 2003 to March 2004, at Santa Bárbara farm, Barreiras–Bahia-Brazil. Data of three samples between December 2003 and March 2004 were analyzed by SAS, using split-plot design, with 10 replications. Infective larvae of Haemonchus spp. and Trichostrongylus spp. were observed on forage in all stratus of vertical layer of the grasses without a defined pattern. Pastures with different characteristics under continuous grazing system had good conditions for developing infective larvae of sheep.

This work was performed aiming to evaluate the morphogenetic and structural characteristics of Andropogon gayanus cv. Planaltina species submitted to three cutting heights (20, 27 and 34 cm). The three cutting heights were allocated in experimental units (12 m²) in a complete randomized block design with three replications. The cuts were done when the light interception by the sward reached 95%. At this moment, the sward height revealed itself constant with values close to 50 cm. The lowest cutting height (20 cm) influenced negatively the final leaf blade length, the number of live leaves, the leaf lifespan, the stem elongation rate and the tiller population density, and it influenced positively the phyllochron and the leaf senescence rate. Probably, cuts at 20 cm height caused a high decapitation and death of the tillers. The worst growth conditions in addition to the blossom of this specie occurred during fall resulted in higher stem elongation rates and number of live leaves, and lower phyllochron, final leaf blade length, and leaf lifespan. The sward height can be used as a practical and efficient criterion in the management of andropogon grass. Under intermittent management conditions, the regrowth of andropogon grass must be interrupted when the sward reaches 50 cm height, and the defoliation must be interrupted when the stubble height is close to 27 cm.Este trabalho foi realizado com o objetivo de avaliar as características morfogênicas e estruturais da espécie Andropogon gayanus cv. Planaltina, submetida a três alturas de corte (20, 27 e 34 cm). As três alturas de corte foram alocadas às unidades experimentais (12 m²) em delineamento de blocos completos casualizados com três repetições. Os cortes foram realizados quando a interceptação luminosa pelo dossel atingiu 95%. A altura do dossel nesse momento mostrou-se constante, com valores próximos a 50 cm. A menor altura de corte (20 cm) influenciou negativamente o comprimento final da lâmina foliar, o número de folhas vivas, a duração de vida da folha, a taxa de alongamento de colmo e a densidade populacional de perfilhos, e positivamente o filocrono e a taxa de senescência de folhas. Provavelmente, cortes a 20 cm de altura causaram elevada decapitação e morte de perfilhos. As piores condições de crescimento junto do florescimento ocorrido durante o outono resultaram em maiores taxas de alongamento de colmos e número de folhas vivas e em menor filocrono, comprimento final da lâmina foliar e duração de vida da folha. A altura do dossel pode ser utilizada como critério prático e eficiente de manejo do capim-andropógon. Em condições de manejo intermitente, a rebrotação deve ser interrompida quando o dossel atingir 50 cm de altura, e a desfolhação, quando a altura de resíduo ficar próxima de 27 cm.

Zeolites are hydrated crystalline aluminosilicate minerals of natural occurrence, structured in rigid third dimension net that can be used as slow release plant-nutrient source. The main objective of this study was to evaluate the effects of plant growth substrate under zeolite application, enriched with N, P and K, on dry matter yield and on nutrient contents in consecutive crops of lettuce, tomato, rice, and andropogon grass. The experiment was carried out in a greenhouse, with 3 kg pots with an inert substrate, evaluated in a randomized block design with three replications. Treatments consisted of four types of enrichment of concentrated natural zeolite: concentrated zeolite (Z) only, zeolite + KNO3 (ZNK), zeolite + K2HPO4 (ZPK) and zeolite + H3PO4 + apatite (ZP), and a control grown in substrate fertilized with a zeolite-free nutrient solution. Four levels of enriched zeolite were tested: 20, 40, 80, and 160 g/pot. Four successive crops were grown on the same substrate in each pot: lettuce, tomato, rice, and andropogon grass. Results indicated that N, P and K enriched zeolite was an adequate slow-release nutrient source for plants. The total dry matter production of above-ground biomass of four successive crops followed a descending order: ZP > ZPK > ZNK > Z.Zeólitas são minerais aluminossilicatos cristalinos hidratados de ocorrência natural, estruturados em redes cristalinas tridimensionais rígidas que podem ser usados como fonte de liberação lenta de nutrientes para as plantas. O objetivo deste trabalho foi avaliar o efeito da adição de zeólita enriquecida com N, P e K ao substrato de cultivo sobre a produção de matéria seca e o acúmulo de nutrientes pelas culturas sucessivas de alface, de tomate, de arroz e de capim-andropogon. O experimento foi conduzido em vasos em casa de vegetação, em vasos contendo 3 kg de substrato inerte. O delineamento experimental foi o de blocos ao acaso, com três repetições. A zeólita natural estilbita foi concentrada e enriquecida com nutrientes N, P e K obtendo-se os seguintes tratamentos: zeólita concentrada (Z), zeólita + KNO3 (ZNK), zeólita + K2HPO4 (ZPK) e zeólita + H3PO4 + apatita (ZP), além de um tratamento testemunha sem adição de zeólita, mas com solução nutritiva. Utilizaram-se quatro doses de zeólita enriquecida: 20, 40, 80 e 160 g/vaso. Foram realizados quatro cultivos sucessivos no mesmo substrato de cada vaso: alface, tomate, arroz e capim-andropogon. Os resultados indicaram que a zeólita enriquecida com N, P e K funcionou como fonte de nutrientes de liberação lenta. A produção de matéria seca total da parte aérea dos quatro cultivos sucessivos seguiu a seguinte ordem decrescente: ZP > ZPK > ZNK > Z.

O presente trabalho foi realizado nas dependências do Departamento de Zootecnia da Escola de Veterinária da Universidade Federal de Goiás, no município de Goiânia, no período de janeiro a abril de 1986. O objetivo foi determinar a composição química dos fenos do capim andropogon (Andropogon gayanus var. bisquamulatus cv. Planaltina) em diferentes idades de corte (40, 54, 68 e 82 dias) após a uniformização. Para estudar a composição química, adotou-se um delineamento em blocos casualizados, com 5 repetições. Determinou-se os teores médios de proteína bruta, de fibra bruta, de matéria mineral, de cálcio e de fósforo. As informações obtidas, neste trabalho, permitiram concluir que apenas a idade de 82 dias, de rebrota, não permitiu a produção de feno com boa composição química. PALAVRAS-CHAVE: Andropogon gayanus; idade de corte; feno; composição química. The present work was done in the annexes of Zootechny Department Veterinary School of the Federal University of Goiás, in Goiânia, from January to April, 1986. The objective was to determine the chemical composition of andropogon grass (Andropogon gayanus var. bisquamulatus cv. Planaltina) at different cutting ages (40, 54, 68 and 82 days) after uniformization, aiming hay. A randomized block design was adapted with 5 replications to study the chemical composition of the hay. Average contests of crude protein, crude fiber, matter mineral, calcium and phosphorus were determined. The information obtained in this work permitted to conclude that only at age of 82 days of regrow it doesn’t permit a haymaking production with chemical composition hay. KEY-WORDS: Cutting age; Andropogon gayanus; chemical composition hay.

Given the environmental damages caused by invasive species, it is critical to allocate limited management budgets carefully. To address this need, there are a variety of approaches for analysing invasive species risk and designing management strategies; these range from pre-border risk assessment through to local-scale prioritisation of management actions. Risk assessment can be broadly characterised into three components: risk analysis, risk characterisation and risk management. For each component we give a brief review of current approaches and then present innovative tools being developed and applied in northernAustralia.We use gamba grass (Andropogon gayanus Kunth.) as a case study to contrast the benefits of the different approaches presented.With our case study, we demonstrate the practical application of novel risk management tools, with results from these tools that are being used locally to prioritise management actions. Lastly, we note that for even greater benefit to be achieved, the new spatial prioritisation approaches presented must be accompanied by further development of data and methods to accommodate planning for multiple weed species and incorporation of further human dimensions (e.g. social and cultural values). [ABSTRACT FROM AUTHOR]

Este trabalho teve como objetivo avaliar a técnica de incorporação de 32P pelos eritrócitos de ovinos jovens, mantidos em pastejo de Andropogon gayanus, como método de diagnóstico da deficiência de fósforo. Vinte ovinos, com peso vivo inicial de 13,88±2,51 kg, foram divididos em dois tratamentos de dez animais cada; num dos tratamentos, os animais foram suplementados com 3 g de P por animal por dia e, no outro, os animais não receberam suplementação de P. Foram realizadas cinco pesagens dos animais, coletas de sangue e fezes nos 8º, 29º, 43º, 57º e 71º dias do experimento, para avaliar a incorporação de 32P pelos eritrócitos, determinar as concentrações de Ca, glicose e P no soro e a porcentagem de P nas fezes. Foi encontrada diferença significativa na concentração de Ca no 57º dia. Na concentração de glicose, porcentagem de P nas fezes e peso vivo não foram observadas diferenças significativas entre os tratamentos. A partir da segunda coleta, a concentração de P no soro foi mais elevada e a incorporação de 32P foi menor no grupo de animais suplementados com P. A incorporação de 32P pelos eritrócitos é uma técnica adicional para avaliar o status de P e identificar sua deficiência subclínica em ovinos jovens.This work had the objective of evaluating the method of 32P uptake by the erythrocytes of young sheep, supplemented with phosphorus and kept at pasture of Andropogon gayanus, as a tool for phosphorus deficiency diagnosis. Twenty lambs, initially weighing 13.88±2.51 kg, were divided in two treatments of ten animals each. In one of them, animals were supplemented with 3 g of phosphorus per animal per day and, in the other, animals did not receive supplementation of phosphorus. Weighing, and blood and faeces collection were carried out in the 8th, 29th, 43rd, 57th e 71st days of the experiment, to evaluate the incorporation of 32P by the erythrocytes, to determine calcium, glucose and phosphorus concentrations in the serum and percentage of P in the faeces. Significant difference for the concentration of Ca was found in the 57th day. For the glucose concentration, the percentage of phosphorus in faeces, and the weight, significant differences between the treatments were not observed. From the 29th to the 71st day, the concentration of phosphorus in the serum was higher, and the incorporation of 32P was lower in the group of animals supplemented with phosphorus. The analysis of 32P incorporation by the erythrocytes is an additional tool to evaluate the status of P, with identification of the subclinic deficiency in lambs.