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

Journal of Animal Science
J C BurnsJ M Luginbuhl

Abstract

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 < .05) for DMI and cubic (P < .05) for digestible DMI. Declines in apparent digestibilities of DM, ADF, and cellulose were cubic (P < .05), whereas these were quadratic (P < .05) for NDF, hemicellulose, and CP. Whole masticates from the least, mid, and most mature hays showed linear (P < .05) declines in DM concentration and IVDMD with increasing maturity, whereas NDF concentrations increased linearly (P < .05). Mean retention time of gastrointestinal DM increased linearly (P < .01) from 64 to 94 h from the least to the most mature hay, and the associated rate of passage declined linearly (P < .01) from 3.3 to 2.1%/h. Sieving of masticate DM showed a reduced proportion of large particles (> or = 2.8 mm) and an increased proportion of small particles (< or = .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 ruminati...Continue Reading

Citations

Dec 8, 2004·Journal of Animal Science·J C BurnsD S Fisher
Jan 19, 1999·Journal of Dairy Science·J L FirkinsN R St-Pierre
Jun 25, 2009·Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology·Angela SchwarmMarcus Clauss
May 18, 2004·Journal of Animal Science·D R StevensJ H Eisemann
Jul 24, 2007·Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology·Marcus ClaussJürgen Hummel

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