| Autor: |
Ferreira G; School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA., Galyon H; School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA., Silva-Reis AI; School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA.; Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes 3400, Argentina., Pereyra AA; School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA.; Facultad de Agronomía y Veterinaria, Universidad Nacional de Río Cuarto, Córdoba 5804, Argentina., Richardson ES; School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA., Teets CL; School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA., Blevins P; Virginia Cooperative Extension, Abingdon, VA 24210, USA., Cockrum RR; School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USA., Aguerre MJ; Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634, USA. |
| Abstrakt: |
The objective of this study was to compare the nutritional composition and the neutral detergent fiber (NDF) degradation kinetics of brown midrib (BMR) and non-BMR genotypes within and across warm-season annual grasses. Four commercial varieties (two non-BMR and two BMR) of corn, sorghum, and pearl millet were planted in plots. Forage samples were incubated in the rumen of three rumen-cannulated cows for 0, 3, 6, 12, 24, 48, 96, and 240 h. On an NDF basis, all forage types showed lower acid detergent lignin (ADL) concentrations for BMR genotypes, but the magnitude of the difference differed among forage types. The concentration of undegraded NDF (uNDF; NDF basis) differed among forage types and between genotypes. Corn had the least, pearl millet had the intermediate, and sorghum had the greatest concentration of uNDF. Non-BMR genotypes had greater concentrations of uNDF than BMR genotypes. No interaction existed between forage type and genotype for the concentration of uNDF. In conclusion, although BMR forages may show lower ADL concentrations in the cell wall and greater NDF degradability than non-BMR forages of the same forage type, BMR forages do not always have the least ADL concentration or the greatest NDF degradability when comparing different forage types. |
