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Tropical Grasslands - Forrajes Tropicales
Journal Prestige (SJR): 0.188

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This is an Open Access Journal

Open Access journal
ISSN (Print) 2346-3775
Published by CIAT

[1 journal]

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Tropicales
- Authors: Bruce G. Cook
  Abstract: Preamble of the Volume 10, Issue 1
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)vii-x
  Issue No: Vol. 10, No. 1 (2022)
Obituary James L Brewbaker
- Authors: Max Shelton
  Abstract: Professor James (Jim) Brewbaker, a great friend to many, and a great supporter of the Leucaena community, died peacefully on March 15, 2021.Obituary from Max Shelton, Assoc. Prof. in Pasture Science from the University of Queensland.
  PubDate: 2022-01-31
  Issue No: Vol. 10, No. 1 (2022)
A maceration treatment of leucaena foliage improves its nutritional value
by reducing mimosine concentration
- Authors: Michael D.H. Honda, Adel Youkhana, Travis Idol, Dulal Borthakur
  Pages: 1 - 14
  Abstract: Giant leucaena produces high dry matter yields but the foliage contains mimosine, a non-protein amino acid that is toxic to animals, especially non-ruminants. Reducing mimosine concentration in foliage following harvesting may allow for greater use of Giant leucaena and mitigate the negative aspects of higher mimosine concentration in some varieties. We evaluated two methods for post-harvest treatment of foliage of a highly productive interspecific hybrid variety ‘KX2’ for reducing mimosine concentration: (i) maceration treatment; and (ii) extraction with 0.1 N HCl. Mimosine as a percentage of leaf dry matter ranged from less than 1% DM to around 3% DM. Although both methods reduced mimosine concentration, extraction by 0.1 N HCl also reduced gross energy, protein and carbohydrate concentrations of leucaena foliage. The maceration treatment, on the other hand, caused little reduction in crude protein and crude fat concentrations but markedly increased the carbohydrate concentration. ADF and NDF concentrations were also reduced as a result of maceration treatment. The estimated gross energy concentration in macerated foliage was not significantly lower than in unprocessed foliage. A suitable mechanical method for post-harvest maceration of leucaena foliage, e.g. a wood-chipping machine, could be used to reduce mimosine concentration in the foliage, making it safer for feeding to livestock and enhancing the feed value, especially for non-ruminants. These methods should be tested by conducting feeding studies to determine the possible benefits in animal performance from feeding macerated foliage.
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)1-14
  Issue No: Vol. 10, No. 1 (2022)
Tropical Grasslands-Forrajes Tropicales Vol.10 No.1
- Authors: TGFT Journal
  Pages: 1 - 77
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)1-77
  Issue No: Vol. 10, No. 1 (2022)
Genetic parameters of growth and biomass in Leucaena leucocephala
for wood energy
- Authors: Rina Laksmi Hendrati, Nur Hidayati, Eko Bhakti Hardiyanto, Mudji Susanto, Liliana Baskorowati, Mashudi Mashudi, Sugeng Pudjiono
  Pages: 15 - 21
  Abstract: Leucaena leucocephala is a potential species for wood-energy production in Indonesia. A study of genetic improvement was initiated with a progeny test of 80 lines from 10 seed sources. Plant height and stem diameter were measured at 6 and 18 months, growth index (GI) calculated at 18 months and wood biomass production measured at 30 months. Differences between seed sources for height and diameter were observed at 6 months but not at 18 months. Significant differences between lines within seed source were observed for height and diameter at 6 months and these differences remained at 18 months. Differences between lines for GI and biomass were significant at 18 and 30 months respectively. At 18 months, line mean heritability for height, diameter and GI were estimated to be moderate, namely 0.62, 0.61 and 0.62 respectively. At 30 months line mean heritability for biomass was moderately low (0.39). Genetic correlations between height and diameter were moderately high at 6 months (0.74) and increased at 18 months (0.82), while correlation between diameters at 6 and 18 months was high (0.93). The expected genetic gain from selecting the 25 and 10 best lines with a high line value for GI was 33.7% and 48.8% respectively, with lines from the Indonesian local seed sources found to be the best performers. Three lines from the newly introduced Tarramba cultivar also had good performance. These results are discussed in relation to the future improvement program of this species for wood energy production.
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)15-21
  Issue No: Vol. 10, No. 1 (2022)
Agronomic characterization of Taiwan grass [Cenchrus purpureus (Schumach.)
Morrone] and evaluation of its potential to produce bioethanol in the warm
sub-humid climate of Mexico
- Authors: Joel Ventura Ríos, José Amador Honorato Salazar, Flora Apolinar Hidalgo, Iliana Barrera Martinez, Jorge Aburto Anell, Humberto Vaquera Huerta
  Pages: 22 - 31
  Abstract: The objective of this study was to evaluate the biomass production, chemical composition, proximate analysis, calorific value and theoretical yield of bioethanol of Taiwan grass under 6 cutting frequencies. The highest production of biomass (33 t DM/ha), cellulose content (41.3%), calorific value (17.5 MJ/kg DM) and potential bioethanol yield (7,936 L/ha) were recorded at a cutting frequency of 180 days. The highest moisture content of the dehydrated samples and ash and crude protein concentrations were observed at a harvest frequency of 30 days with 9.2, 12.1 and 10.5%, respectively. The highest concentrations of extractives were obtained at harvest frequencies of 60 and 120 days (13.9 and 13.7%, respectively), while lignin concentrations were greatest at harvest frequencies of 150 and 180 days (21.1 and 20.9%, respectively). The highest concentration of fixed carbon was observed at a harvest frequency of 90 days (18.5%), while the lowest concentration of volatile matter occurred at a harvest frequency of 30 days. The data indicate that Taiwan grass has significant potential for use to produce bioethanol but assessment of the carbon footprint, life cycle analysis, energy yield (energy produced:energy consumed) of the entire production process is needed to ensure there are positive effects on climate change and greenhouse gas emissions before this process is adopted.
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)22-31
  Issue No: Vol. 10, No. 1 (2022)
Canopy responses of signal grass cv. Basilisk pastures subjected to three
fertilization regimes at two stubble heights
- Authors: Bruna Scalia De Araújo Passos, Valdo Rodrigues Herling, Manoel Eduardo Rozalino Santos, Lucas Da Rocha Carvalho, Lilian Elgalise Techio Pereira
  Pages: 32 - 43
  Abstract: The impacts of fertilization regimes and stubble heights in signal grass cv. Basilisk pastures were evaluated during late
  spring and summer in Brazil. Liming and N, P and K fertilization were applied to generate gradients in soil fertility to
  maintain soil base saturations around 35%, 50% and 65%, increase soil P concentration and the proportion of K in soil
  cation exchange capacity, combined with two stubble heights of 10 and 15 cm. Herbage accumulation was not affected
  by fertilization regimes and stubble height reaching 10 t/ha of dry matter during the growing season. Cutting at 10
  cm maximizes the leaf mass and leaf area index and decreases dead material mass without the need of high soil base
  saturation and NPK fertilization rates to sustain plant growth. However, this stubble height required longer regrowth
  periods to attain 95% of light interception (LI95%). A stubble height of 15 cm is preferred when short regrowth periods are required. The canopy height at the point of LI95% does not change with fertilization regimes, but the LI95% is reached at different canopy heights in late spring and summer in signal grass pastures. The adoption of a moderate fertilization regime is recommended as a strategy to obtain an equitable forage distribution between late spring and summer.
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)32-43
  Issue No: Vol. 10, No. 1 (2022)
Effects of different supplements on performance of steers grazing Mombaça
guineagrass (Megathyrsus maximus) during the dry period
- Authors: Camile Sanches Silva, Valéria Pacheco Batista Euclides, Denise Baptaglin Montagner, Itânia Maria Medeiros de Araújo, Gelson dos Santos Difante, Marco Antonio Previdelli Orrico Júnior
  Pages: 44 - 51
  Abstract: To mitigate the low animal performance on Mombaça guineagrass pasture during the dry period, feeding 2 types of
  supplement to 2 genetic groups was evaluated. The experimental design was a randomized block design following a 2 ×
  2 factorial arrangement with 4 replications. The treatments consisted of feeding 2 levels of supplement (0.25 and 1.0% of body weight; BW), named low-cost supplement (LCS; US$ 11.75/steer) and high-cost supplement (HCS; US$ 62.80/steer), respectively, for 130 days (July–October; dry season) to 2 genetic groups: Caracu and F1 Senepol × Caracu. The steers were supplemented daily and weighed every 28 days. Pastures were evaluated monthly to estimate the herbage accumulation rate, herbage mass (HM), leaf, stem and dead material percentages and nutritive value. HM, morphological components and nutritive value were independent of supplement type fed (P>0.05). There were decreases in HM (3,720 to 3,205 kg DM/ha), daily herbage allowance (14.0 to 9.4 kg DM/100 kg BW) and leaf percentage (33.4 to 21.2%) and increase in dead material percentage (53.3 to 67.7%) throughout the experimental period. In vitro organic matter digestibility (59.9%), crude protein concentration (10.0%), neutral detergent fiber (72.1%) and acid detergent lignin (2.9%) remained constant from July to September but increased markedly in October. Steers supplemented with HCS performed better (P<0.05) than those which received LCS (1.005 vs. 0.565 kg liveweight gain/head/day, respectively). Regardless of supplement type, F1 Senepol × Caracu steers had greater average daily gains than pure Caracu steers (0.88 vs. 0.71 kg/hd/d, respectively). Feeding HCS to steers in the dry season would produce better performance than LCS and could reduce time to reach slaughter weight but weight changes during the subsequent wet season should be monitored to assess the extent of any compensatory gain by the low-cost group during this period to reduce the weight advantage of the high-cost group.
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)44-51
  Issue No: Vol. 10, No. 1 (2022)
Evaluation of land use change on an andosol through physicochemical and
biological indicators
- Authors: Maria-Cristina Ordoñez, Leopoldo Galicia, Juan Fernando Casanova Olaya
  Pages: 52 - 62
  Abstract: The conversion of forests to agricultural land can dramatically alter soil properties, but soil resistance, which is the
  ability of soil properties or processes to remain unchanged in the face of a specific disturbance or stress, remains
  unclear. We evaluated the impact of land use change and agricultural management on changes on an andosol in the
  Cauca department, Colombia, through the analysis of physicochemical variables and biological indicators (dimensionless
  resistance index, where +1 is the highest resistance and -1 is the lowest resistance) that allowed the assessment of soil
  resistance. The land uses analyzed included (1st) forest, which was approximately 100 years of age, plus areas of the same forest (70% of the area), which had been replaced by (2nd) natural pastures and (3rd) forage crops in the year 1985, i.e. 30 years before the observations. All physicochemical variables except soil clay content were significantly affected by the change from forest to natural pasture. Similarly, the change from forest to forage cropping affected all physicochemical variables as well as resulting in a decrease in soil microbial biomass but an increase in microbial activity. We found that the metabolic quotient (-0.32) had the lowest resistance, followed by the microbial coefficient (0.19), microbial biomass (0.32) and microbial activity (0.39), suggesting that soil stress caused by disturbance has a marked impact on the number and activity of the soil microflora. By contrast the change from forest to natural pastures was not associated with any effect on microbial biomass and its activity, suggesting that the continuous input of organic matter to the soil through the supply of organic residues from diversified root systems and nutrients from livestock urine and manure favored the preservation and resistance of microbial processes in the soil. These findings suggest that deforestation to establish natural pasture has less impact on soil stability and health than cultivating the soil following clearing.
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)52-62
  Issue No: Vol. 10, No. 1 (2022)
Phenotypic and genetic variability induced in Lehmann’s love grass
(Eragrostis lehmanniana) through gamma irradiation
- Authors: Alan Álvarez-Holguín, Carlos R. Morales-Nieto, Carlos H. Avendaño-Arrazate, Raúl Corrales-Lerma, Federico Villarreal-Guerrero
  Pages: 63 - 68
  Abstract: This study assessed the morphological and nutritional diversity induced through gamma irradiation in Lehmann’s
  love grass. Seed were irradiated at doses of 0, 100, 200, 300, 450, 600, 900, and 1400 Gy. Ten agronomic traits related
  with forage quality were evaluated and used to select the mutants, which were confirmed by cluster analysis and
  multivariate analysis of variance and then characterized by nutritional and molecular characterization. Mutants with
  16–20% less (p<0.05) lignin and 36–68% more protein content than the control genotype were found. Genetic distances of 0.38 and 0.49 also revealed differences (p<0.05) between the mutants and control genotype. The phenotypic and genetic variability, induced through gamma irradiation, resulted in the identification of two first generation mutants with outstanding agronomic traits and nutritional quality.
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)63-68
  Issue No: Vol. 10, No. 1 (2022)
Nutritive value of forages and diets in some small-scale dairy farms in
Kiambu County, Kenya in the short rains season
- Authors: Gianni Matteo Crovetto, Francesco Magnoli, Maria Chiaravalli, Timoty Njeru, Jhon Waweru Gitau, Stefania Colombini
  Pages: 69 - 77
  Abstract: Sixteen selected small-scale dairy farms were investigated in Kiambu County (Kenya) during the short rains season
  to develop a snapshot of the types of rations fed, milk yields obtained and sources of fodder. On average farmers had
  1 ha of land and 2.2 lactating cows yielding 8.93 kg milk/cow/d with feed intake of 10.5 kg DM/d. Only 35% of feed
  consumed was produced on farm. Boma Rhodes grass hay and green Napier grass were the main forage components
  (37.9 and 28.3% of total DM). Protein forages used were the herbaceous legumes lucerne and desmodium (19.9 and
  15.9% CP, respectively) and leguminous shrubs (Leucaena, Calliandra and Sesbania with 21.1% CP and 43.4%
  aNDFom, on average). Grasses had higher aNDFom digestibility (47.1%) than legumes (39.7%). Napier grass, Boma
  Rhodes grass, lucerne and desmodium had fiber digestibility of 51.9, 48.6, 46.8 and 32.6%, respectively. The energy
  and protein balances (actual vs. requirements) of the cows were on average -19.3 and -16.4%, respectively, indicating
  that cows utilized body tissues to produce the levels of milk obtained. Mutiple correspondence analysis showed that a
  milk yield higher than 9.1 kg/d was associated with a level of Boma Rhodes grass <5 kg DM/d, concentration of nonfibrous carbohydrates in the diet >22.0% (DM basis), concentrate level >2.63 kg/cow/d and CP% in the ration >9.1%. To improve milk yields during this season farmers should harvest grass forage at a younger age, include leguminous forage in the diets and increase the level of concentrates fed. These strategies should be demonstrated on farms to show possible benefits.
  PubDate: 2022-01-31
  DOI: 10.17138/tgft(10)69-77
  Issue No: Vol. 10, No. 1 (2022)