Abstract

OBISPO, Néstor E et al. Effect of shaded on the production and quality of guinea grass (Panicum maximun) in a silvopastoril system. Zootecnia Trop. [online]. 2008, vol.26, n.3, pp.285-288. ISSN 0798-7269.

In a cattle farm in the Yaracuy state, Venezuela, a research was carried out to evaluate the effect of shade density on biomass yield and on the quality of the guinea grass (Panicum maximun). With the aid of satellite images and the analysis of cartographic charts, in four grassland areas, it was determined the canopy surface of the trees and their respective densities of shade. In these densities of shade (High, >30%; medium, between 20-30%; low <10% and without shade), considered as treatment, 15 points of sampling were set to harvest the contained Guinean grass in a 0.25 m² square frame, to determine the amount biomass kg/ha, the crude protein (PC), detergent fibers, neutral (NDF) and acid (ADF), contents, and the in vitro digestibility. The greater yields (P<0.05) were observed for the low (14,045.9) and without shade (14,318.8) densities, with intermediate values in the medium shaded area (10,065.3), and the lowest for the high shaded (8,859.6). The PC contents were similar in all the densities, with an average value of 13.2 ± 0.36%, with a numerical tendency to be higher with the increases in the shaded. NDF content diminished (P<0.05) with the increases in the density of shaded, with values of 71.7, 69.9, 73.2 and 76.3%, for the high, medium, low and without shade treatments, respectively. ADF contents were uniform in the shaded areas with an average value of 33.7%, but smaller for the forages in quite sunny area (42.6%). The digestibility of the forage was higher (P<0.05) for the forages in the high and medium shaded areas with values of 62.6 and 65.9, respectively, and lower in the low and without shade areas (59.4 and 59.4, respectively).

Keywords : forage quality; shade; digestibility; yield; Panicum maximum.

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