Suchergebnisse

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.

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.