Gradients in fracture force and grazing resistance across canopy layers in seven tropical grass species

Jacobs, A. A. A., Scheper, J. A., Benvenutti, M. A., Gordon, I. J., Poppi, D. P. and Elgersma, A. (2013) Gradients in fracture force and grazing resistance across canopy layers in seven tropical grass species. Grass and Forage Science, 68 2: 278-287. doi:10.1111/j.1365-2494.2012.00900.x

Author Jacobs, A. A. A.
Scheper, J. A.
Benvenutti, M. A.
Gordon, I. J.
Poppi, D. P.
Elgersma, A.
Title Gradients in fracture force and grazing resistance across canopy layers in seven tropical grass species
Journal name Grass and Forage Science   Check publisher's open access policy
ISSN 0142-5242
Publication date 2013-06
Year available 2013
Sub-type Article (original research)
DOI 10.1111/j.1365-2494.2012.00900.x
Open Access Status
Volume 68
Issue 2
Start page 278
End page 287
Total pages 10
Place of publication West Sussex, United Kingdom
Publisher Wiley-Blackwell
Collection year 2014
Language eng
Formatted abstract
In reproductive swards, stems can act as a barrier that affects the grazing behaviour of ruminant livestock. The barrier effect of stems is closely associated with both the force required to fracture the stems and the density of these stems (in combination, these make up grazing resistance), and these factors need to be considered when making predictions about the forage intake of ruminants grazing reproductive pastures. Differences in grazing resistance between sward canopy layers of different grass species are thought to affect bite dimensions, but data are scarce. In this study, we assessed the grazing resistance for three canopy layers of seven tropical grass species. Species differed significantly in grazing resistance for every canopy layer, with a general ranking order for grazing resistance, in ascending order: Cenchrus ciliaris (‘American' buffel), Digitaria milanjiana (‘Jarra’ finger grass), Setaria surgens (annual pigeon grass), Setaria sphacelata (‘Narok’ setaria), Dichanthium sericeum (Queensland bluegrass), Chloris gayana (‘Callide’ Rhodes grass). In the top canopy layer, grazing resistance did not appear to create a barrier for any of the species, but in the bottom canopy layer, it did for all species. Species also differed in the relative contribution of fracture force and density to grazing resistance. The results highlight the importance of managing the grazing systems to minimize the barrier effect of the stems, which can be done by controlling the phenological stage of the pasture and the grass species and animal size used in the system.
Keyword Bite dimensions
Biting force
Leaf measurements
Tiller density
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Veterinary Science Publications
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Citation counts: TR Web of Science Citation Count  Cited 1 times in Thomson Reuters Web of Science Article | Citations
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