Adauton Vilela de Rezende

Produção e qualidade da forragem de capim-marandu fertiirrigada com dejetos líquidos de suínos

Esta pesquisa foi realizada com o objetivo de avaliar os efeitos da fertilizacao com dejetos liquidos de suinos (DLS) nas caracteristicas agronomicas e bromatologicas da forragem de capim-marandu. Foram avaliados a produtividade de MS, o perfilhamento, o percentual de MS, PB, FDN e FDA e a digestibilidade in vitro da MS (DIVMS). Adotou-se o delineamento em blocos casualizados, com nove tratamentos (adubacoes) e quatro repeticoes. Os tratamentos sao descritos a seguir: T1 - uso de calcario; T2 - adubacao com 100, 40 e 60 kg/ha de N P K; T3 - 180 m3 de DLS/ha 1x/ano; T4 - 180 m3 de DLS/ha 2x/ano); T5 - 180 m3 de DLS/ha 3x/ano; T6 - 180 m3 de DLS/ha 4x/ano; T7 - 180 m3 de DLS/ha 5x/ano; T8 - 180 m3 de DLS/ha 1x/ano (in natura); T9 (testemunha) - fermentacao do DLS utilizado nos tratamentos 1, 2, 8 e 9 por, no minimo, 45 dias. As medias foram comparadas pelo teste Scott-Knott. Na calagem, utilizou-se alcario dolomitico na proporcao de 3 t/ha e, na adubacao quimica, 100, 40 e 60 kg/ha de N, P2O5 e K2O nas formas de sulfato de amonia supersimples e cloreto de potassio. Os cortes foram realizados a cada 45 dias. O numero de perfilhos/m2, a produtividade de MS e a qualidade da forrageira foram maiores com a utilizacao de DLS em dose unica nos primeiros cortes. As forrageiras dos tratamentos 3, 4, 8 e 9 apresentaram maiores teores de PB nos primeiros cortes, com medias de 9,6 a 13,7%. Os maiores teores de FDN foram obtidos no segundo corte (medias de 61,4 a 68,6%) e os menores de FDA foram encontrados com DLS 2x/ano e 5x/ano no primeiro corte (medias de 21,2 a 23,4%). Os tratamentos 3, 4 e 8 proporcionaram os maiores coeficientes de DIVMS no primeiro corte, com medias de 69,0 a 71,8%.

Valor nutritivo de silagens de milho colhido em diversos estádios de maturação

This work evaluated the bromatologic characteristics of corn silages, ensiled at different maturity stages. It was used a split plot in time in a randomized block design, with four replicates. Cultivars evaluated were Geneze 2004, Agroceres 1051, Pioneer 30S40 and Pioneer 30F90 ensiled in the following maturity stages: 0% milk line kernels (SLL), reduction of milk line in 1/3 of the kernel (1/3 LL), 1/2 of the kernel (1/2 LL), 2/3 of the kernel (2/3 LL), and formed black layer (CN). The percentage of DM of the silages ranged from 26.5% to 45.0%. The highest losses of effluents occurred in the silages from the cultivars AG1051 and P30S40, at the SLL stage, with no losses from the 1/2 LL stage. As the maturity stage advanced, increased values of pH occurred. Maturity stages influenced the percentage of CP of the silages which ranged from 10.7% to 8.1%. The greatest values of NDF (neutral detergent fiber) and ADF (acid detergent fiber) were found at the 2/3 LL and CN stages. The percentage of lignin was influenced by the cultivars, with the greatest values observed in the silages from the cultivar P30S40. The IVDDM (in vitro dry matter digestibility) was influenced by cultivar and maturity stage, varying from 51.1% to 69.8%, with the cultivar P30F90 presenting the greatest IVDDM. The 1/2 LL stage showed better IVDDM, reducing its value after this stage. The cultivars GNZ 2004, AG1051 and P30F90 are more indicated for ensiling and the best maturity stage for ensiling these two cultivars was when grains presented reduction of the milk line in half of the kernel (1/2 LL).

Chemical and microbiological characteristics of sugar cane silages treated with microbial inoculants.

The aim of this research was to evaluate the effect of microbial additives containing heterofermentative or homofermentative bacteria on the chemical and microbiological characteristics of sugar cane (Saccharum spp) silages. Sugar cane was inoculated with Lactobacillus plantarum, L. paracasei, L. brevis or L. buchneri previously isolated from sugar cane silages or commercial inoculants containing L. buchneri or L. plantarum. Silages were produced in laboratory silos (10 × 60 cm PVC tubes) and evaluated 90 days after ensiling. A randomized complete design was used with eight treatments (seven inoculants and control - without inoculant) and three replications. The inoculation with bacteria affected lactic acid bacteria, yeast populations, volatile fatty acids and ethanol contents in the silages. Inoculation with different strains of the same species of bacteria result in silages with different chemical and microbiological characteristics. Two of the L. buchneri strains show the best results in relation to silage quality.

Chemical and fermentative changes during the storage period of the sugar cane silage with or without ground dried ear corn.

The chemical and fermentative changes of the sugar cane ensiled without or with (control) ground dried ear corn (GDEC) were evaluated during 100 days of storage period. The pH values, buffer capacity (BC), dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HM) ammonia nitrogen in relation to the total nitrogen (N-NH3/TN) were evaluated. The experiment was conducted in a complete randomized design as a factorial (2 × 21) scheme with three replications. The factor A was composed of sugar cane silage with or without GDEC, and the factor B was the 21 storage periods. The data were submitted to the regression analyses. The pH values decreased in the first five days of storage, from 5.2 to 3.5 and from 5.2 to 3.6, respectively on the silage without and with GDEC. Silages with GDEC showed higher pH values when compared to the control, on average of 0.09 units. The inclusion of GDEC resulted in higher N-NH3/TN values in all storage periods. In the control silage, the reduction on the DM content was 14.1 units and 8.8 units for those with GDEC. The inclusion of GDEC resulted in the reduction of 17.0 units in the NDF, probably due to the low fiber content of the additive. Sugar cane silage presents chemical changes up to 100 days of storage, and should not remain stored for long periods.The chemical and fermentative changes of the sugar cane ensiled without or with (control) ground dried ear corn (GDEC) were evaluated during 100 days of storage period. The pH values, buffer capacity (BC), dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HM) ammonia nitrogen in relation to the total nitrogen (N-NH3/TN) were evaluated. The experiment was conducted in a complete randomized design as a factorial (2 × 21) scheme with three replications. The factor A was composed of sugar cane silage with or without GDEC, and the factor B was the 21 storage periods. The data were submitted to the regression analyses. The pH values decreased in the first five days of storage, from 5.2 to 3.5 and from 5.2 to 3.6, respectively on the silage without and with GDEC. Silages with GDEC showed higher pH values when compared to the control, on average of 0.09 units. The inclusion of GDEC resulted in higher N-NH3/TN values in all storage periods. In the control silage, the reduction on the DM content was 14.1 units and 8.8 units for those with GDEC. The inclusion of GDEC resulted in the reduction of 17.0 units in the NDF, probably due to the low fiber content of the additive. Sugar cane silage presents chemical changes up to 100 days of storage, and should not remain stored for long periods.

Efeito da altura de corte das plantas na produtividade de matéria seca e em características bromatológicas da forragem de milho

Este trabalho foi conduzido com o objetivo de avaliar a producao de materia seca e a composicao bromatologica da forragem de cultivares de milho submetidos a duas alturas de corte das plantas (altura 1 - 0,1 m e altura 2 - 0,8 m) em tres anos de cultivo no municipio de Lavras, MG. Os experimentos foram instalados em area experimental do Departamento de Agricultura da Universidade Federal de Lavras (UFLA) nas safras agricolas 1998/1999, 1999/2000 e 2000/2001, empregando-se cinco cultivares de milho no primeiro ano e seis nos anos seguintes. Os experimentos foram conduzidos sob o delineamento de blocos casualizados em esquema fatorial 5 x 2 e 6 x 2, sendo cinco ou seis cultivares de milho e duas alturas de corte, com tres repeticoes. Avaliaram-se as caracteristicas produtividade de materia seca (MS) e teores de proteina bruta (PB), fibra em detergente neutro (FDN) e fibra em detergente acido (FDA) na MS. Detectou-se efeito significativo das alturas de corte em todas as caracteristicas estudadas. Os teores de PB aumentaram e os de FDN e FDA diminuiram com a elevacao da altura de corte das plantas. Comparando-se as duas alturas de corte, verificou-se que houve uma reducao de 3,3 t.ha-1 na produtividade de MS, um aumento de 0,6% no teor de PB, uma reducao de 4,4% no teor de FDN e uma reducao de 3,9% no teor de FDA com a elevacao da altura de corte de 0,1 para 0,8 m. Os resultados obtidos permitiram concluir que a elevacao da altura de corte, embora tenha contribuido para a diminuicao da producao de MS, proporcionou uma melhoria na qualidade da forragem em decorrencia da parte mais fibrosa e menos digestivel da planta de milho nao ter sido colhida.

Perdas fermentativas e estabilidade aeróbia de silagens de milho inoculadas com bactérias ácido-láticas em diferentes estádios de maturidade

The aim of this work was to evaluate the inoculation of lactic acid bacterial in corn silages produced in different development stages on the fermentative losses and aerobic stability. The experimental design was completely randomized in factorial scheme 3x5 evaluating two commercial inoculants (Silobac® and Maize All®) and a control treatment (silage untreated) in five maturity stages with four replicates. The application of Silobac® and Maize All® decreased the dry matter losses during the fermentative process in 1.78 and 1.75 percentage points when compared to control silage (7.95%). The silages produced with 2/3 of milk line and black layer presented lower dry matter losses due mainly to the lower effluent production. The higher aerobic stability was observed in a silage produced with corn plants in the black layer stage and inoculated with Maize All®, where there was lower aerobic stability than other silages inoculated with the same product due to increase of moisture of the silages. The inoculants used in this work are efficient in decrease the dry matter losses during the fermentative process, however, there is higher concentration of nutrients in this silages resulting in lower stability after the opening of the silos. Silages produced with higher dry matter content present higher dry matter losses, as well as more stability during the aerobic exposure.

Silagens de milho inoculadas microbiologicamente em diferentes estádios de maturidade: perdas fermentativas, composição bromatológica e digestibilidade in vitro

The aim of this study was to evaluate the fermentative losses, chemical composition and in vitro organic matter digestibility of corn silages produced in different maturity stages microbiologically inoculated. Two commercial inoculants were applied in the silages produced in stages SLL, 1/3 LL, 1/2 LL, 2/3 LL and CN, remaining an uninoculated treatment (control silage), illustrating a factorial scheme 3 x 5. The lactic acid bacteria (LAB) inoculation resulted in lower fermentative losses (P=0.0348), whereas silages produced with dried plants present lower DM losses (P<0.01). Because of inoculant application, there was higher concentrations of CP in the silages produced in stages SLL, 2/3 LL and CN (P=0.0033) and concentration lower of NDF (P=0.0140) in CN stage because of the Maize All® inoculant. This inoculant provided increase in the IVOMD coefficients when the plants were harvested with 2/3 LL and CN (P= 0.0006). Fermentative losses decreased because of the use of microbial inoculants, and this fact it is also observed in silages produced with dried plants. Application of lactic acid bacteria (Maize All® inoculant) in corn silages produced with plants harvested in more advanced stages of maturity improve the chemical composition and in vitro digestibility.

Nitrogênio e as características anatômicas, bromatológicas e agronômicas de cultivares de Brachiaria brizantha

With the objective of determining some anatomical and physicochemical characteristics of two cultivars of Brachiaria brizantha cvs. Marandu and MG-5 Vitoria, harvested at 45 and 65 days after planting under growing doses of ,nitrogen (N), an assay was conducted in pots in greenhouse of the Science Department in the Federal University of Lavras - UFLA, Lavras, MG. An experimental randomized block design with the treatments arranged in a factorial scheme 2x2x5 was used, with, two genotypes, two cutting ages and five doses of N (0, 100, 200, 300 and 400 mg/dm3) with four replicates totalizing to 20 treatments and 80 experimental units (pots). The variables studied were: tiller density, polar and equatorial diameters of stomata on the adaxial and abaxial leaf surfaces, CP, NDF and ADF contents and IVDMD coefficients. The results allow to verify that increased doses of N influences positively DM yield at the two cutting ages. The cutting age influences the number o tillers, the density and polar and equatorial diameters of stomata and the cultivar Vitoria presents more plastic in the stomata characteristics compared to the cultivar Marandu. Higher doses of N cause increase in the contents of CP and IVDMD. Lower inter-curtting intervals promoted the lowest contents of NDF and ADF.

Influence of stage of maturity on bromatological quality of corn forage

The objective of this study was to evaluate the effects of stalk/leaf ratio and the stage of maturity on the digestibility of the corn plant. Hybrids AG1051, AG4051, AG5011, DOW2B710, DOW2C577, DOW2A525, NB7315 and P30F90 were used, harvested at the one-half milk line (½ ML), three-quarters milk line (¾ ML) and black layer (BL) stages. A randomized block design was used in an 8 (hybrids) × 3 (stages of maturity) factorial design, with three replications. The means generated were used for grouping into high and low stalk/leaf ratio and a new analysis of variance was generated in a 2 × 3 (two groups and three stages of maturity) factorial design. The whole plant and its stalk, leaf, husk, cob and grain components were incubated in situ in the rumen of three cows for determination of degradability of dry matter and degradable neutral detergent fiber. Stalk/leaf ratio did not influence neutral detergent fiber content or the degradability of dry matter and neutral detergent fiber of any of the components, except for the cob, in which the high ratio group had greater degradable neutral detergent fiber contents. There was a reduction in the degradability of all the parts, except for the stalk and cob, and an increase in the neutral detergent fiber contents of the vegetative parts, except for the stalk. Unlike the vegetative components, the neutral detergent fiber contents of the whole plant decreased throughout the stages evaluated. For degradable neutral detergent fiber, there was a reduction in the whole plant and in its components. The advance of maturity reduces the quality of the vegetative components; however, this loss in the entire plant is moderated by grain filling. Forage quality depends more on the quality of the components than on their proportions in the dry matter.

Replacement of aruana grass by gliricidia (Gliricidia sepium) on silage quality

Our objective was to investigate the effect of the replacement of aruana grass by gliricidia on the fermentative losses, chemical composition, and aerobic stability of silages. For ensiling, whole-crop aruana grass (75 d of growth) was chopped (275 g kg-1 dry matter - DM) and ensiled alone or associated with gliricidia (270 g kg-1 DM; 150 d of growth). For gliricidia, we used only the leaves and stalks to ensile. The evaluated treatments were different ratios of aruana grass to gliricidia (100:0, 75:25, 50:50, 25:75, and 0:100), with four replicates (mini-silos). The silage composed only of gliricidia exhibited a lower pH than the other silages. Dry matter recovery was not affected by the treatments, although effluent losses were affected. The replacement of aruana grass by gliricidia 50% at ensiling resulted in a higher lactic acid bacteria count. The aruana grass silages displayed lower protein contents and a higher neutral detergent fiber content than the gliricidia silages after 40 d of fermentation. Consequently, the silage consisting of 100% gliricidia showed higher in vitro DM digestibility, presenting an increase of 8.13% after 40 d of fermentation compared with 100% of aruana grass silage. After silo opening, the gliricidia silage was very stable (>72 h). The low quality of aruana grass silage is improved by replacing this grass with significant amounts of gliricidia (approximately 75%).