Abstract

GRANADOS-NINO, Jorge A. et al. Effect of the cutting height of sorghum at harvest on forage yield and nutritional value of silage. Rev. mex. de cienc. pecuarias [online]. 2021, vol.12, n.3, pp.958-968.  Epub Mar 14, 2022. ISSN 2448-6698.  https://doi.org/10.22319/rmcp.v12i3.5724.

The objective was to identify an optimal cutting height at harvest of sorghum forage (Sorghum bicolor L.) to improve the nutritional quality of silage, without reducing the dry matter (DM) yield of the forage. The effect of cutting height at 10, 20, 30, 40, 50 and 60 cm on DM yield and nutritional value of silage was evaluated. The forage was harvested when the grain reached a milky-dough state. The plants were crushed to a particle size of 2 cm and the forage was compacted to 261 kg of MS/m3 in mini silos. The DM yield reduced from harvesting at 40 cm above the ground. The neutral detergent fiber (NDF) and lignin of silage were superior when harvested at 10 cm, but lignin reduced by 1.4 % when the cut was greater than 20 cm. The NDF digestibility and total digestible nutrient (TDN) concentration increased when harvested at 40 cm. The highest content of non-fibrous carbohydrates (NFC) was obtained when harvested at 40 and 50 cm. The net lactation energy (NLE) of silage increased from harvesting at 20 cm. The optimal pH of silage was obtained when harvested at 30 cm. In conclusion, harvesting the sorghum fodder between 20 and 40 cm allows obtaining a silage with lower lignin content and, therefore, greater digestibility and energy concentration without negatively affecting the DM yield of the forage.

Keywords : Sorghum bicolor (L.); Dry matter yield; Silage; Cutting height; Nutritional value.

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