Avaliação qualitativa e anatômica de gramíneas forrageiras sob pastejo no agreste pernambucano.

Abstract

Reviews of nutritional value and proportion and arrangement of tissues is important in understanding the potential of forage plants. The study was conducted at the Experimental Station Caruaru belonging to the Agronomic Institute of Pernambuco - IPA. The objective was to evaluate the chemical composition and anatomical characteristics of exotic grasses under grazing of cattle in Agreste of Pernambuco. The experimental design was a randomized complete block design with four replications. The plots consisted of beds of 25m ² (5m x 5m) and 9m ² (3m x 3m) of floor area. The experimental treatments consisted of three species of exotic grasses (grass-bufel - Cenchrus ciliares Linnaeus; Lemongrass pangolão - Digitaria pentzii Stent. Genotype and Panicum maximum Jacq. Spontaneous region), evaluated under grazing from May to September 2011, totaling five grazing cycles. The cycles were performed every 35 days, with one day of rest from grazing and 34. We used rotational grazing with cattle and animals in pastejadores Mob grazing, aiming to average height of post-grazing residual of 20 cm. The samples were collected by means of simulated grazing, pregrazing and post-grazing. The variables were analyzed for chemical composition of dry matter, crude protein, acid detergent fiber, neutral detergent fiber corrected for ash and nitrogen, lignin and digestibility. To anatomy and areas were measured phloem, xylem, vascular sheath, abaxial and adaxial epidermis, sclerenchyma, mesophyll, vascular bundle total and counted the numbers of vascular bundles. Data were statistically analyzed using the Proc Mixed of SAS (Statistical Analysis System) and means were compared by LSMEANS 5% probability, but for some variables the chemical was used Proc ANOVA, SAS (1999). Data obtained from the analysis of tissue proportion were processed using the Proc ANOVA and means were compared by Tukey test at 5% probability. Observed for evaluations of simulated grazing, significant difference (P<0.05) for the variables DM, NDF, ON. The Panicum showed a higher proportion of tissue virtually indigestible.