Trocas gasosas e desidratação em diferentes intensidades de condicionamento no capim Tifton 85: valor nutricional durante o armazenamento do feno

Abstract

The present study aimed to evaluate the intensity of conditioning of plants Tifton 85 with use of Mower Conditioner with free swinging flail fingers and storage times on the curve of dehydration, occurring fungus, nutritional value and in vitro digestibility of dry matter of hay Tifton 85. During the dehydration of the plants was also evaluated gas exchange. The dehydration curve was determined in the whole plant in ten times to the baling. The zero time corresponded to the plant before the cut, held 11h00 hour and other collects were made 8h00, 10h00, 14h00 and 16h00 hours. The experimental design was randomized blocks with two intensity of conditioning (high and low) and tem times of sampling, with five replicates. For the determination of gas exchange during the dehydration Tifton85 Evaluations were performed on mature leaves, situated in the upper middle third of each branch before the cutting and were performed each hour, for 4 hours. We used a portable meter infrared gas analyzer IRGA (6400 at). The variables analyzed were (A) photosynthesis, (gs) stomata conductance, (C) internal CO2 concentration, (E) sweating, (EUA) efficiency of water use, (EUAi) intrinsic efficiency to the water use. Subsequently the determination of fungi present in green plants and hay, where the grass samples were collected at the time of cutting , baling in, 30, 60 and 90 days of storage was made. It was observed that the dehydration of Tifton 85 was held in 49 hours, who is considered an ideal time for drying hay and differences between intensities of conditioning about on dry matter were taken during dehydration, but equaled the end of process. Gas exchanges were more intense before the cut, and, after cutting were decreasing to cease within 4 hours. The dry matter (DM) is smaller on the time when cutting when compared to other storage times. The crude protein did not differ between the intensity of conditioning or storage times staying on average 121.65 g kg-1. The lowest values of acid detergent insoluble protein (PIDA) were obtained with low intensity of conditioning after 30 days of storage, 64.8 g kg -1 DM. The contente of neutral detergent fiber (NDF), didn´t result no difference both to the time before the cut as to intensity of conditioning of Tifton 85. The in vitro digestibility of dry matter (DM) of Tifton 85 did not differ on the times of storage evaluated or difference on the intensities of conditioning. In samples collected during the storage period up to 90 days after dehydration was not detected the presence of fungi, with less than 30 colony forming units (CFU) per plate count. The use of mowers Conditioners in diferente intensities of injury does not accelerate the time of dehydration plants Tifton 85. Proper drying and storage under favorable conditions do not favor the growth of fungi in Tifton 85