A total of six barley by-products (three brewers' grains (BG1 and BG3) and three
barley rootlets (BR1, BR2, and BR3) used in this study. The samples were obtained
commercially and dried at 508C till constant weight.
A subsample from BG1 was selected to study the effect of drying temperature on
rumen degradability and intestinal digestibility. Samples were either untreated (freezedried;
UBG) or heat treated at different temperatures. Samples were introduced into an
air-forced oven, the temperature was registered at 10 min intervals and the average value
was calculated. Mean temperature and times of drying for each treatment were as follows:
508C for 11 h (50BG), 1008C for 4 h and 35 min (100BG), 1358C for 2 h and 8 min
(135BG), and 1758C for 1 h and 55 min (175BG). At the end of the heat treatment, dry
matter (DM) content of the samples was always higher than 96%. It must be pointed out
that BG1 corresponds with 50BG for all the experimental results. The chemical
composition of the experimental feeds is given in Table 1.
2.2. Animals