Effect of period of regrowth on chemical composition and ruminal degradability from forage Dichanthium aristatum (Angleton)

In the present work, the chemical composition of the grass Dichanthium aristatum (Angleton) to different period of regrowth (21, 28, 35, 42 and 49 days) and its degradation "In situ" to different times from incubation (0.12, 24.36, 48 and 72 hours) was evaluated. The results of the chemical analysis highly denoted significant differences in the percentage of crude protein to the 21 days with a reduction as it increased the of period of regrowth; the greater reached value was of 13, 6%. The levels of dry matter, lignin, organic matter, FDN, FDA and ash did not register significant differences. The dates of ruminal degradation were submitted to the variance analysis through the General Model Lineal (GML) process of SAS® 8.1 and the comparison of medias were done by means of Tukey probe. Significant differences in the MS, FDA and FDN parameters, between ages of regrowth from 21 and 28 days with respect to the others were observed; while degradation of PB was different significantly in the age of regrowth of 21 days with respect to the anothers. These dates suggest that as the plant aged became less degradable.According to the obtained results, based on the chemical analysis and the ruminal degradation it is deduced that to 21 days of its regrowth, the pasture owns a higher nutritious value considering that its quality is based on the protein content and fiber assimilation. En el presente trabajo se evaluó la composición química del pasto Dichanthium aristatum (Angleton), a diferentes edades de corte (21, 28, 35, 42 y 49 días) y su degradabilidad "In situ" a diferentes tiempos de incubación (0,12, 24,36, 48 y 72 horas). Los resultados del análisis químico denotaron diferencias altamente significativas en el contenido de proteína bruta (PB), a los 21 días con un descenso a medida que aumentó la edad de corte; el mayor valor alcanzado fue de 13, 6. Los niveles de materia seca, lignina, materia orgánica, Fibra Neutro Detergente (FDN), Fibra Ácido Detergente (FDA), y ceniza no registraron diferencias significativas. Los datos de degradabilidad ruminal se sometieron a un análisis de varianza a través del procedimiento de modelos lineales generales, GML de SAS® 8.1 y la comparación de medias se hizo a través de la prueba de Tukey; observándose que existe diferencias significativas entre las edades de corte de 21 y 28 días con respecto a las demás, en los parámetros de MS, FDA y FDN; mientras que la degradabilidad de PB, fue significativamente diferente en la edad de