Resumo

ROA, María Ligia  e  GALEANO, J. R. Nutritional quality and digestibility in situ of silages from four woody forages. Pastos y Forrajes [online]. 2015, vol.38, n.4, pp. 431-440. ISSN 2078-8452.

The effect of the conservation time on the nutritional quality and the in situ digestibility of silages from four woody forage plants: Cratylia argentea (T1), Hibiscus rosa-sinensis (T2), Trichanthera gigantea (T3) and Tithonia diversifolia (T4), was evaluated. The plants were pruned after six months of establishment and three months after regrowth, and the leaves and small young branches were used to elaborate 64 silos of 10 kg each, in plastic bags. Each conservation time (0, 30, 60 and 90 days) had four repetitions. To calculate the digestibility of dry matter (DM), total nitrogen (TN), neutral detergent fiber (NDF) and the parameters of effective digestibility (ED), four rumen-fistulated cattle were used, distributed in a 4 x 4 Latin square. The silages showed nice aspect and color, with pH between 4,2 and 4,6 and ammoniacal nitrogen lower than 1 %. The TN percentage was higher for T1 (2,52) and T2 (2,43), and this nutrient was reduced until 90 days. The ED of the DM, TN and NDF was higher (p < 0,05) in T2, with a trend to decrease with the conservation time (90 days). This same performance was shown by fractions A, B and c. The highest lignin content appeared in T3 (5,45 %) and T4 (5,60 %), indicator that affected negatively the rumen kinetics. The decrease of the nutritional quality and digestibility due to the conservation time was lower for T2 and T3. It is concluded that the organoleptic properties of the silages were optimum, the ammoniacal nitrogen did not exceed 1 % and the lactic acid varied between 1,0 and 3,6 %; while time affected to a lower extent the nutritional composition of the silage of H. rosa-sinensis, with regards to the other forage plants. It is recommended to ensile for the dry season and use the silages before 60 days of conservation

Palavras-chave : Cratylia argentea; Hibiscus rosa-sinensis; Tithonia diversifolia; Trichanthera gigantea; nutritional value.

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