Changes in forage quality, ingestive mastication, and digesta kinetics resulting from switchgrass maturity

• Published in: Journal of animal science Vol. 75; no. 5; p. 1368
• Main Authors: Burns, J.C. (USDA, ARS, Raleigh, NC.), Pond, K.R, Fisher, D.S, Luginbuhl, J.M
• Format: Journal Article
• Language: English
• Published: United States 01.05.1997
• Subjects: Animal Feed - standards; Animals; Biomarkers; BOEUF; BOVIN DE BOUCHERIE; BUEY; Cattle - physiology; CELLULOSE; Cellulose - metabolism; CELULOSA; Chromium - analysis; CONTENIDO DE MATERIA SECA; Dietary Fiber - metabolism; Dietary Fiber - standards; DIGESTA; DIGESTIBILIDAD; DIGESTIBILITE; DIGESTION; Digestion - physiology; Digestive System Physiological Phenomena; EXPERIMENTACION IN VITRO; EXPERIMENTATION IN VITRO; FECES; Fermentation; FIBRA DE LA DIETA; FIBRE ALIMENTAIRE; FOIN; GANADO DE CARNE; GROSSEUR DES PARTICULES; HECES; HEMICELLULOSE; HEMICELULOSA; HENO; INGESTION DE PIENSOS; MADUREZ; Male; MASTICACION; MASTICATION; Mastication - physiology; MATEMATICAS; MATHEMATIQUE; MATURITE; Nutritive Value; PANICUM; Particle Size; Poaceae - metabolism; Polysaccharides - metabolism; PRISE ALIMENTAIRE (ANIMAUX); PROTEINA BRUTA; PROTEINE BRUTE; TAMANO DE LA PARTICULA; TECHNIQUE DE PREVISION; TECNICAS DE PREDICCION; TENEUR EN MATIERE SECHE; Time Factors; VALEUR NUTRITIVE; VALOR NUTRITIVO; Ytterbium - analysis
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/1997.7551368x

Five maturities of switchgrass hay harvested at 14-d intervals (vegetative through 20% heading) were fed to Hereford steers (297 kg) in a 5 X 5 Latin square. Relationships with switchgrass maturity were negative and quadratic (P 0.05) for DMI and cubic (P 0.05) for digestible DMI. Declines in apparent digestibilities of DM, ADF, and cellulose were cubic (P 0.05), whereas these were quadratic (P 0.05) for NDF, hemicellulose, and CP. Whole masticates from the least, mid, and most mature hays showed linear (P 0.05) declines in DM concentration and IVDMD with increasing maturity, whereas NDF concentrations increased linearly (P 0.05). Mean retention time of gastrointestinal DM increased linearly (P 0.01) from 64 to 94 h from the least to the most mature hay, and the associated rate of passage declined linearly (P 0.01) from 3.3 to 2.1%/h. Sieving of masticate DM showed a reduced proportion of large particles (greater than or equal to 2.8 mm) and an increased proportion of small parties (less than or equal to 0.5 mm) with advancing forage maturity. More than 94% of the sieved fecal DM passed a 1.0-mm sieve, but particle sizes showed the same relationship with forage maturity as noted for masticate DM. This occurred despite the comminution from the rumination and digestive processes