Journal of Animal Science, Vol 69, Issue 3 1188-1198, Copyright © 1991 by American Society of Animal Science

JOURNAL ARTICLE

Effects of grass species on grazing steers: I. Diet composition and ingestive mastication

D. S. Fisher, J. C. Burns, K. R. Pond, R. D. Mochrie and D. H. Timothy
Dept. of Crop Sci., North Carolina State University, Raleigh 27695-7620.

In traditional grazing trials, per animal and per hectare productivity are determined, but pasture and animal measurements are generally inadequate to address reasons for different treatment responses. This 2-yr study examined the diet and diet characteristics of steers grazing tall fescue (Festuca arundinacea Schreb.), switchgrass (Panicum virgatum L.), flaccidgrass (Pennisetum flaccidum Griseb.), and bermudagrass (Cynodon dactylon [L.] Pers.) pastures. A randomized complete block design was used with two agronomic replicates. In vitro DM disappearance (IVDMD) of masticates from tall fescue (TF), switchgrass (SG), and flaccidgrass (FG) generally were similar; all exceeded 70% (70.3 to 79.9%), except for bermudagrass (BG), which was lowest (63.5 to 65.0%). Sieving the masticate DM showed BG to contain the highest proportion (20 to 29%) of particles passing a .5-mm sieve and the lowest proportion (6 to 8%) of particles retained on a 2.8-mm sieve. This resulted in BG having the smallest mean (1.29 mm) and median (1.08 mm) particle sizes in yr 1 and a mean (1.10 mm) and median (.91 mm) particle size smaller than SG in yr 2. Except for BG, the IVDMD of the masticate DM was lowest for small particles. Canopies showed BG and SG to have the highest proportion of stem (47 and 52%, respectively); the BG canopy was composed of fractions that were consistently lowest in IVDMD. In general, BG offered the grazing animal a canopy inferior in IVDMD concentration and had canopy characteristics that limited the animals' selection of a diet with quality as high as that of TF, SG, or FG.

This article has been cited by other articles:

				J. C. Burns and D. S. Fisher 'Coastal' and 'Tifton 44' Bermudagrass Availability on Animal and Pasture Productivity Agron. J., August 11, 2008; 100(5): 1280 - 1288. [Abstract] [Full Text] [PDF]

				M. J. Hersom Opportunities to enhance performance and efficiency through nutrient synchrony in forage-fed ruminants J Anim Sci, April 1, 2008; 86(14_suppl): E306 - E317. [Abstract] [Full Text] [PDF]

				G. B. Huntington, J. C. Burns, and S. L. Archibeque Urea metabolism in beef steers grazing Bermudagrass, Caucasian bluestem, or gamagrass pastures varying in plant morphology, protein content, and protein composition J Anim Sci, August 1, 2007; 85(8): 1997 - 2004. [Abstract] [Full Text] [PDF]

				J. C. Burns and D. S. Fisher Dry Matter Intake and Digestibility of 'Coastal', 'Tifton 44', and 'Tifton 85' Bermudagrass Hays Grown in the U.S. Upper South Crop Sci., March 1, 2007; 47(2): 795 - 808. [Abstract] [Full Text] [PDF]

				J. C. Burns Grazing Research in the Humid East: A Historical Perspective Crop Sci., December 2, 2005; 46(1): 118 - 130. [Abstract] [Full Text] [PDF]

				Y. C. Newman, L. E. Sollenberger, and C. G. Chambliss Canopy Characteristics of Continuously Stocked Limpograss Swards Grazed to Different Heights Agron. J., September 1, 2003; 95(5): 1246 - 1252. [Abstract] [Full Text] [PDF]

				J. C. Burns and L. E. Sollenberger Grazing Behavior of Ruminants and Daily Performance from Warm-Season Grasses Crop Sci., May 1, 2002; 42(3): 873 - 881. [Abstract] [Full Text] [PDF]