Suchergebnisse

This study evaluated the nutritional value of sugarcane varieties in relation to nitrogen fertilization. The varieties studied were RB 863129, RB 867515, and RB 92579, and nitrogen fertilizer was applied at doses of 0, 60, 80, 120, and 140 kg N ha-1. The experiment was divided into two stages: i) Year I - plant cane, when the yield and nutritional quality of the three sugarcane varieties were evaluated; ii) Years II and III, when and the effect of nitrogen fertilization on the nutritional quality of the first and second ratoon crops of the same varieties was evaluated. In plant cane the yield (t ha-1) and DM (dry matter) and CP (crude protein) contents were higher for the RB 863129 variety. There was no difference between the varieties regarding their NDF (neutral detergent fiber) and ADF (acid detergent fiber) contents and IVDMD (in vitro dry matter digestibility). In the first and second ratoon crops, there was a difference between the varieties and fertilizer doses for the evaluated parameters, with the exception of the DM content and IVDMD, which were influenced by the varieties, doses of N, and cutting years. The RB 92579 variety showed the best yield of the two ratoon crops (131 t ha-1 of stems) and the best nutritional parameters (26% ADF, 41% NDF, 2.4% CP, and 69.4% IVDMD). The sugarcane yield and its nutritional quality can be influenced by the cutting year and nitrogen fertilization management system and by the variety type.

This study aimed to evaluate how different irrigation water depths influence the agronomical features of elephant grass (Pennisetum purpureum Schum) cv. Roxo. Grass was cultivated in a pasture belonging to the Bovine Sector of the National Agrotechnical School of Caceres – MT. The experiment was a block design with five treatments and four repetitions. Treatments consisted of five water depths: 0 = 0% of available water (AW), 1 = 21% of AW, 2 = 34% of AW, 3 = 74% of AW, and 5 = 100% of AW. Evaluated features were production (dry matter ha-1), plant height, leaf/steam ratio, and stem diameter. Dry matter production of cuts from May and July increased linearly with increasing water depth (P < 0.05). Plant height increased linearly as water depth increased in the cuts of May and September, while the height of July cuts was 71.76 cm under an irrigation depth of 390.77 mm. In May, July, and September cuts, leaf percentage decreased linearly as water depth increased (P < 0.05). An increase of 1 mm in water depth reduced leaf percentage by 0.0936% (May), 0.0295% (July), and 0.0122% (September). Our results indicate that to improve dry matter production, May, July, and September cuts should be irrigated with water depths of 56.03 mm, 601.78 mm, and 577.65 mm, respectively.

This study aimed to evaluate the interception of light (%IL), leaf area index (LAI), and the chemical and productive characteristics of elephant grass (Pennisetum purpureum Schum) under different defoliation frequencies (30, 45, 60, 75, and 90 days after cutting). The experimental design was completely randomized with five replications and five treatments (cutting frequencies). The chemical composition was analyzed in a factorial arrangement 2 ×5 (two fractions: leaf and stem, and five defoliation frequencies). The pattern of variation in IL and LAI in function of the frequency of cutting was ascending order. The maximum values of %IL and LAI occurred at 75 and 90 days after cutting with 98.46%; 98.72% (%IL) and 7.08; 8.10 (LAI), respectively. There was no effect of cutting frequency on the total yield of forage, leaf production, generation of stem and dead material, tillers alive, dead tillers and height. Only the leaf/stem ratio was not influenced (P > 0.05) among the factors studied. The frequency of cutting influenced (P < 0.05) the chemical composition, where decreased cutting frequency significantly increased the levels of dry matter, neutral detergent fiber, acid detergent fiber, cellulose, and ash in two fractions evaluated (leaf and stem); the crude protein content showed a decline from the moment the frequency of cutting was increased. The LAI, and productive and chemical characteristics of elephant grass were influenced by increased frequency of cutting. Limiting the cutting of the grass to 60 days implies an optimal point of production and quality.

This study aimed to evaluate the agronomic characteristics and nutritional value of Massai grass (Megathyrsus maximus 'Massai') pastures fertilized with different nitrogen levels and subjected to deferred grazing. A completely randomized experimental design (CRD) was adopted, with including five nitrogen levels (zero, 100, 200, 300, and 400 kg ha?1), and five replications (plots). The degradability trial used a CRD including a 6 × 5 factorial arrangement, consisting of six rumen-incubation times (6, 24, 48, 60, 84, and 96 h) and five levels of nitrogen in different plots. One fistulated sheep, with a live weight of 60 kg, was used in the experiment. Total herbage biomass, dead herbage biomass, and height showed a quadratic response to nitrogen fertilization levels of 100 to 200 kg ha-1 resulted in greater tillering. Protein and dry matter content increased linearly with nitrogen fertilization level, leading to increase in fibrous components. The increase in NDF and ADF contents might be a consequence of the reduction in NCE, and the high flowering rate of the grass, owing likely to the reduction in metabolism of the grass in an attempt to extend its lifetime. Nitrogen levels of 300 kg ha?1 or higher affected the productive characteristics positively, whereas the chemical characteristics were negatively affected.

The aim of the present study was to evaluate the performance, animal behavior, and contamination and spread of nematode larvae of sheep supplemented with increasing levels of protein (15, 25, and 35%) on Xaraés grass (Brachiaria brizantha 'Xaraés') pastures. Fifteen Santa Inês crossbred sheep, with an average age of approximately five months and average initial weight of 14.63 kg, were used in the experiment. The feeding behavior (grazing and idle times) of animals was found to be influenced by the supplementation provided. The highest level of supplementation provided to the animals reduced their grazing time. The different levels of supplementation influenced the average daily gain and total final body weight gain of the sheep in Xaraés grass pastures. A significant difference was observed in the presence of parasitic larvae in the Xaraés grass pastures depending on different protein levels throughout the regrowth period. The number of larvae in feces was influenced by the protein content of the supplement, and varied throughout the pasture rest period. Animals showed a decrease in the number of larvae as their dietary crude protein (CP) content was increased. Supplementation with high protein, together with the action of vermifuge, increased the performance of sheep and reduced their parasite load and grazing time in Xaraés grass pastures.

The objective of this study was to evaluate the effect of cutting age on the production, chemical composition, degradation kinetics and anatomy of Leucena (Leucaena leucocephala). The experimental design was a completely randomized design with a factorial arrangement 2x4 (two types of tissues and four cutting ages) for the production data of dry matter and 3x4 (three degrees of degrees of digestion of tissues and four cutting ages). Observed effect (P < 0.05) for the total production of DM of Leucena in function of different ages. The tissue types grain and non-grain showed maximum production at 70 days of age, with production of 2333,00 and 716.60 kg DM ha-1, respectively. The parameters of degradation of DM evaluated decreased significantly with the increase in the maturity of the plant, in the same way the chemical composition presented behavior inherent to the advance of age. The effective degradability DM also decreased with the increase in the rate of passage (2, 5, and 8% h-1). The highest rate of degradation (c) was obtained for 30 days. With the advance in plant maturity increases the proportion of vascular tissue lignificad influencing parameters of ruminal degradation of Leucena. The ages assessed influenced the chemical composition of the Leucena (P < 0.05), where the levels of dry matter, crude protein, acid detergent fiber and lignin and ash showed increasing linear behavior. The cutting age of 70 days offers an optimal point regarding the proportion of anatomical tissues correlated with the degradation and chemical composition of the Leucena.

he aim of this study was to evaluate fermentation and chemical characteristics and the in situ degradability of sorghum silages enriched with dried Leucaena. The experiment was conducted as completely randomized design with four treatments (0 - control silage, silage without leucaena; 10.0, 20.0, or 30.0% inclusion of Leucaena) and five replicates, totaling 20 experimental units. The inclusion levels of leucaena influenced (P 0.05), with all silages having values above 90%. Gas loss decreased (P < 0.05) as the level of leucine increased in sorghum silage. A linear increase was observed for dry matter (P ? 0.0001) and crude protein (P = 0.0008) contents in response to Leucaena inclusion. There was a linear (P < 0.05) linear effect on neutral detergent fiber, hemicellulose and acid detergent fiber. As leucaena inclusion levels increased, for each 1% inclusion a reduction of 0.179 was observed; 0.059 and 0.119% for the values of neutral detergent fiber, hemicellulose and acid detergent fiber respectively. The inclusion of leucaena influenced (P < 0.05) the increase of silage lignin levels, probably due to the higher lignin content of the legume. The soluble fraction (a) of the silages increased along with the Leucaena inclusion levels, with highest values observed at the inclusion of 20 and 30% of the legume, respectively. Potential degradation (A) increased linearly with the levels of Leucaena added to the silage; the highest value for this variable was observed at 30% inclusion. Effective degradability (ED) increased up to the inclusion level of 20% (46.77%). Degradation rate (c) decreased markedly with the use of 30% Leucaena. The use of the forage part of Leucaena dried for three hours leads to reduced gas production, increased dry matter and crude protein contents, and decreased fiber contents. The degradability of dry matter increases up to the inclusion level of 20%.