effects of the source of non-fiber carbohydrates on in vitro first order ruminal disappearance kinetics of dry matter and ndf of various feeds

an in vitro experiment was conducted to study the effect of non-fiber carbohydrates (nfc) on ruminaldisappearance kinetics of dry matter (dm) and neutral detergent fiber (ndf) of alfalfa hay, wheat bran andunmolassed sugar beet pulp. non-supplemented or nfc supplemented samples [70 mg/g dm of each feedsample as sucrose (su) or starch (st) or su + st as 1:1] were incubated in bottles containing 40% rumenfluid medium for 4, 8, 16, 24, 48, and 96 h at 39°c. after each incubation time, unfiltered content wasanalysed for dm and ndf. filtered fluid was analysed for ammonia-n concentration. kinetic disappearancerate was determined using a first order non-linear model. the source of nfc used in the medium containingalfalfa hay caused a significant decrease in dm disappearance (p