title: Effects of particle size of processed barley grain, enzyme addition and microwave treatment onin vitrodisappearance and gas production for feedlot cattle.
abstract: OBJECTIVE
  The effects of particle size of processed barley grain, enzyme addition and microwave treatment onin vitrodry matter (DM) disappearance (DMD), gas production and fermentation pH were investigated for feedlot cattle.
  
  
  METHODS
  Rumen fluid from four fistulated feedlot cattle fed a diet of 860 dry-rolled barley grain, 90 maize silage and 50 supplement g/kg DM was used as inoculum in 3 batch culturein vitrostudies. In Experiment 1, dry-rolled barley and barley ground through a 1-, 2-, or 4-mm screen were used to obtain four substrates differing in particle size. In Experiment 2, cellulase enzyme (ENZ) fromAcremonium cellulolyticusY-94 was added to dry-rolled and ground barley (2-mm) at 0, 0.1, 0.5, 1, and 2 mg/g, while Experiment 3 examined the interactions between microwaving (0, 30, and 60 s microwaving) and ENZ addition (0, 1, and 2 mg/g) using dry-rolled barley and 2-mm ground barley.
  
  
  RESULTS
  In Experiment 1, decreasing particle size increased DMD and gas production, and decreased fermentation pH (p<0.01). The DMD (g/kg DM) of the dry-rolled barley after 24 h incubation was considerably lower (p<0.05) than that of the ground barley (119.1 dry-rolled barley versus 284.8 for 4-mm, 341.7 for 2-mm; and 358.6 for 1-mm). In Experiment 2, addition of ENZ to dry-rolled barley increased DMD (p<0.01) and tended to increase (p = 0.09) gas production and decreased (p<0.01) fermentation pH, but these variables were not affected by ENZ addition to ground barley. In Experiment 3, there were no interactions between microwaving and ENZ addition after microwaving for any of the variables. Microwaving had minimal effects (except decreased fermentation pH), but consistent with Experiment 2, ENZ addition increased (p<0.01) DMD and gas production, and decreased (p<0.05) fermentation pH of dry-rolled barley, but not ground barley.
  
  
  CONCLUSIONS
  We conclude that cellulase enzymes can be used to increase the rumen disappearance of barley grain when it is coarsely processed as in the case of dry-rolled barley. However, microwaving of barley grain offered no further improvements in ruminal fermentation of barley grain.
authors: Shimizuko shiryo Co., Ltd., Ishinomaki, Miyagi, 981-3109, Japan.
authors: Shin-Ichi
authors: SI
authors: Tagawa
authors: Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
authors: Lucia
authors: L
authors: Holtshausen
authors: Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
authors: Tim A
authors: TA
authors: McAllister
authors: Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
authors: Wen Zhu
authors: WZ
authors: Yang
authors: Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
authors: Karen Ann
authors: KA
authors: Beauchemin
keywords: Barley Grain; Enzyme; Gas Production; In vitro Dry Matter Disappearance; Particle Size; Rumen Fluid