Carlos Henrique Oliveira Macedo

Agronomic evaluation of 32 sorghum cultivars in the Brazilian semi-arid region

The objective of this study was to evaluate agronomic characteristics of 32 sorghum cultivars (Sorghum bicolor(L). Moench) in the Brazilian semi-arid region. The experimental design was set up in randomized blocks with three replications. Treatments were the 32 sorghum cultivars. The evaluated variables were: plant height, stem diameter, tiller density, number of green leaves per tiller, average leaf length, dry matter content, fresh matter production and dry matter production (DMP) in kg/ha, and the percentage of the components panicle, leaf blade and stem. To avoid associative effects due to the presence of positive correlation with DMP, the variables plant height, number of plants per hectare and fresh matter production were excluded for being part of the discriminatory variables of the cluster. Based on the cluster analysis and subjective cutting in 20% dissimilarity, five groups were hierarchically set up. It was not possible to find groups with higher values of panicle and DMP simultaneously; however, group number 5 met significant values for both variables, with mean values of 15,037.63 kg/ha of DMP and 11.36% of panicle, besides 13.65% of leaf. Groups 3, 4 and 5 show high potential for dry matter production, especially group 5. The presence of evident variation among cultivars allows for a selection of more productive and, thus, more suitable cultivars for silage production in semi-arid regions.

Perfil fermentativo e composição bromatológica de silagens de sorgo em função da adubação nitrogenada

Two experiments were conducted to evaluate the fermentation characteristics and chemical composition of sorghum silage. In the first experiment the fermentative profile of sorghum silages in response to nitrogen fertilization was evaluated using a completely randomized design, in split-plot scheme with five doses of nitrogen (in the plot) and six opening times (in the subplot). The nitrogen levels were 0; 50; 100; 150 and 200kg/ha and the opening times were: 1; 3; 7; 14; 28and 49 days after ensiling. In the second experiment the variations in the chemical composition of sorghum silages was evaluated. The experimental design was randomized blocks with five repetitions, and the treatments consisted on the same levels of fertilization of first experiment. Dry matter increased linearly with the nitrogen and the fermentation period. The pH increased linearly as a function of nitrogen and showed a quadratic response as a function of fermentation period. The N- NH3 values showed a quadratic response both to nitrogen as for the opening day. Organic matter increased linearly and mineral matter decreased. Lignin responded linearly to increasing nitrogen fertilization. The hemicellulose decreased linearly. The dry matter, pH and ammonia values show efficacy in the silage fermentation process independent of nitrogen level used. The use of fertilizer is an interesting practice, which increases plant productivity without changing the chemical composition of the silage. Nevertheless, for the most economic treatment, is indicated the use of 150kg of nitrogen per hectare.

Lactic Acid Bacteria in Tropical Grass Silages

The basic principle silage is to store the surplus forage keeping its stability and nutritional value until it is required to feed the animals. This process takes place in anaerobic conditions, where the lactic acid produced by the LAB inhibits the proliferation of spoilage microorganisms, which are less tolerant to acidic conditions. Thus, as the pH values decline, the silage losses decline as well due to the greater conversion of plant soluble carbohydrates (the main substrate for LAB) in lactic acid, with 96.9% rate of energy recovery (Mc Donald et al., 1991). The major soluble carbohydrates present in forage crops are fructose, glucose, sucrose and frutosanas, according to Woolford, (1984), sucrose and frutosanas are rapidly hydrolyzed in their monomers at forage harvest.

Microbial and fermentation profiles, losses and chemical composition of silages of buffel grass harvested at different cutting heights

The present study evaluated the microbial population, fermentation profile, losses and dry matter recovery, and chemical composition of silages of buffel grass at different cutting heights. To evaluate the microbial fermentation dynamics, the treatments resulted from a 4 × 5 factorial combination consisting of 4 cutting heights and 5 fermentation periods, in a completely randomized design with three replications. The fermentation was evaluated at the end of 1, 3, 7, 15 and 30 days. The other characteristics of silages with 30 days were evaluated following a completely randomized design with four treatments, consisting of 4 cutting heights (30, 40, 50 and 60 cm), and five replications. Fermentation period and cutting height effects and interaction between both factors were observed on the populations of lactic acid bacteria (LAB), enterobacteria and molds and yeasts. The peak of development of LAB populations was observed on the seventh day of fermentation for the heights of 40 and 50 cm, with 8.25 and 8.30 log cfu/g, respectively. The pH values of silages ranged with different cutting heights, in which at the height of 50 cm the decrease was most pronounced. However, the pH values were similar between the cutting heights at the end of 30 days of fermentation. Quadratic relationship was observed between lactic acid concentrations and cutting heights. The crude protein content behaved linearly, initially showing 128.5 g/kg DM at 30 cm, decreasing as the cutting heights increased. The neutral detergent fiber and ether extract contents increased linearly with the cutting heights. Based on microbial populations, fermentation, losses and chemical composition, it is recommended to harvest buffel grass for silage from 50 cm on.

Silages of pearl millet submitted to nitrogen fertilization

This study aimed to evaluate the fermentation characteristics, losses and the chemical composition of two pearl millet genotypes silages submitted to nitrogen fertilization. The experimental design was a completely randomized blocks in a split plot scheme 2x5 (two nitrogen genotypes doses x five doses of nitrogen), with four replicates. Nitrogen doses were 0, 20, 40, 60, 80kg ha-1 and the pearl millet genotypes were the variety ADR300 and the hybrid ADR7010. The hybrid ADR 7010 showed average lactic acid content higher than the variety ADR 300, at all doses of N, recording values ranging from 4.09 to 10.46dag kg-1. There was an interaction between nitrogren doses and genotypes for the neutral detergent fiber, which ranged from 51.81 to 63.63dag kg-1 of dry matter. Dry matter recovery decreased linearly with increasing nitrogen doses only for hybrid ADR7010, the same did not happen for the ADR300. The nitrogen fertilization does not favor the fermentation characteristics and increases DM losses of the hybrid ADR7010.

Cinética de fermentação ruminal in vitro de silagens de híbridos de sorgo

The aim of this research was to evaluate the silage of 23 sorghum hybrids using the in vitro semi-automatic gas production technique. A completely randomized design with 23 treatments was used, with three replications, and treatments were the sorghum-hybrids silages. Hybrids were grown at the experimental station of the Instituto Nacional do Semiarido (INSA), in Campina Grande - PB. The gas production was estimated using the bicompartimental logistic model, adjusted to the curves of cumulative gas production. A significant effect (P<0.05) was observed for final gas of fibrous carbohydrates (VfCF), which results ranged from 105.99 to 144.53mL/g of DM. Degradation rate of fibrous carbohydrates (KdCF) values ranged (P<0.05) for the hybrid 866041, which showed the highest result 0.015h-1. Final total volume (VFT) was affected by hybrid (P<0.05), in which hybrids 870085, Volumax and XBS60329 had the highest (P<0.05) values compared to other hybrids. By multivariate analysis were formed six distinct groups. Group 2, consisting of hybrids 22 (Volumax) and 23 (XBS60329) showed the highest average values for gas volumes, both for fibrous carbohydrates and for the non-fibrous. Group 4, comprising the hybrid 1 (866005), had the lowest gas volume produced means and a highest lag time (3.15 hours). All hybrids studied have potential to silage, according to the ruminal fermentation kinetics.

Avaliação de genótipos de milheto para silagem no semiárido

The objective of this research was to evaluate the forage yield, agronomic characteristics and morphometric plants and losses, fermentation and chemical composition of silages of pearl millet genotypes. To evaluate the agronomic and morphometric characteristics of genotypes it was used the randomized blocks experimental design with five replicates. In the phase of silos evaluation the design has become completely randomized design with four replications. Cultivars tested were Sauna B, CMS 01, ADR 500, BRS 1501 and CMS 03. There was no difference for PFF, DMP and DM. The pearl millet genotypes had a average PMV of 9073 kg/ha in the first cycle and 10.054kg/ha in the regrowth. As to the leaf and stem production there was not difference in both cuts. The concentration of AL ranged from 1.98 to 5.17% for genotypes B and CMS SAUNA 01, respectively. For the crude protein there was a significant effect among genotypes studied, with values ranging from 11.56 to 7.90%. The genotypes studied were equivalent in both the evaluation of the plants and the evaluation of silage, which can be used as an alternative fodder in semiarid regions.

Divergence of the fermentative and bromatological characteristics of 25 sorghum hybrid silages

The objective of this study was to evaluate the divergence of bromatological and fermentative characteristics of silages of 25 sorghum (Sorghum bicolor L. Moench) hybrids. The experimental design was completely randomized with 25 treatments and four replications. The mean values of pH differed with variation from 3.45 to 3.87 for hybrids 866005 and 870051, respectively, and the mean pH value was 3.66. The average percentage of lactic acid ranged from 2.90 to 7.43 dag/kg of dry matter (DM) in hybrids 870035 and 866005, respectively, with an average of 4.65 dag/kg DM. Through cluster analysis by the Tocher method and average Euclidean distance based on the fermentative characteristics, five groups were formed: one with 18 hybrids, another with four and three groups with one hybrid in each. In group three, there were the hybrids that showed the highest values of lactic acid. Hybrids 870025, 870035, 870081, 870095, 866034, and 870031 showed higher DM content and the hybrid BRS 610 had the lowest average compared with the others. Hybrids 1F305, BRS 610, Volumax, and XBS60329 had the lowest levels of non-fiber carbohydrates and higher neutral detergent fiber corrected for ash and protein. Despite the fermentative and bromatological divergences between hybrids, they are not a limiting factor to silage production.