*Dairy Cattle Nutrition Div., National Dairy Research Institute, Karnal, l32 001
Department of Animal Sciences, University of Nebraska, Lincoln. USA
Online published on 29 December, 2011.
Geometric mean diameter of wheat straw particles following its chopping to pass through the screen size of 0.95 cm was 650 micrones. Modulus of fniformity and modulus of fineness of such straw was 3:5:2 and 5.34, respectively. Chopped straw was fractionated into large (>1.18mm), medium (>0.425mm and < 1.18mm) and fine (>0.17mm and <0.425mm)’particles and their fibre (NDF) digestion kinectics was determined using in situ technique. Lag time for NDF digestion of chopped particles was longer (11.71h) than fine particles (4.36h). Rate of fibre digestion decreased with the reduction of particle size. Rate and potential extent of fibre digestion were lowest for fine particles, however, particle size did not influence the later parameter significantly. Apparent extent of NDF digestion (%) was highest for chopped straw and decreased (P<0.05) on reducing into fine particle. It can be inferred that processing of wheat straw into fine particles does not favour the utilization of its fibre content.
