title: Differences in the nutrient concentrations, in vitro methanogenic potential and other fermentative traits of tropical grasses and legumes for beef production systems in northern Australia.
abstract: BACKGROUND
  In northern Australia, beef cattle grazed extensively on tropical rangelands are responsible for 5% of the nation's total greenhouse gas emissions. Methane (CH4) is a potent greenhouse gas and in grazing ruminants might be mitigated by selecting forages that, when consumed, produce less CH4when fermented by rumen microbes. This study examined variability in the in vitro fermentation patterns, including CH4production of selected tropical grasses and legumes, to identify candidates for CH4mitigation in grazing livestock in northern Australia.
  
  
  RESULTS
  Nutritive values and fermentation parameters varied between plant species and across seasons. Grasses with a relatively low methanogenic potential were Urochloa mosambicensis (wet summer), Bothriochloa decipiens (autumn), Sorghum plumosum (winter) and Andropogon gayanus (spring), while the legumes were Calliandra calothyrsus (wet summer and autumn), Stylosanthes scabra (winter) and Desmanthus leptophyllus (spring). There was some correlation between CH4production and overall fermentation (volatile fatty acid concentrations) in grasses (R2= 0.67), but not in legumes (R2= 0.01) and there were multiple plants that had lower CH4not associated with reduction in microbial activity.
  
  
  CONCLUSIONS
  Differences in nutrient concentrations of tropical grasses and legumes may provide opportunities for productive grazing on these pastures, while offering some CH4mitigation options in the context of northern Australian extensive beef farming systems. © 2017 Society of Chemical Industry.
authors.affiliation: School of Agriculture and Environment, The University of Western Australia, Crawley, WA, Australia.
authors.forename: Zoey
authors.initials: Z
authors.lastname: Durmic
authors.affiliation: CSIRO Agriculture, James Cook University, Townsville, QLD, Australia.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Ramírez-Restrepo
authors.affiliation: School of Veterinary and Biomedical Sciences, James Cook University, Townsville, QLD, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Gardiner
authors.affiliation: CSIRO Agriculture, James Cook University, Townsville, QLD, Australia.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: O'Neill
authors.affiliation: School of Agriculture and Environment, The University of Western Australia, Crawley, WA, Australia.
authors.forename: Eman
authors.initials: E
authors.lastname: Hussein
authors.affiliation: School of Agriculture and Environment, The University of Western Australia, Crawley, WA, Australia.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Vercoe
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001315:Australia; D002417:Cattle / Q000378:metabolism*; D007887:Fabaceae / Q000737:chemistry / Q000378:metabolism*; D008697:Methane / Q000032:analysis / Q000378:metabolism; D009753:Nutritive Value; D006109:Poaceae / Q000737:chemistry / Q000378:metabolism*; D000069466:Red Meat / Q000032:analysis; D012417:Rumen / Q000378:metabolism
chemical_list: D008697:Methane
keywords: Australian plants; CH4; beef; forage; grazing; rumen fermentation