Feeding value of wheat-based thin stillage: In vitro protein degradabilityand effects on ruminal fermentation

Two experiments were conducted to evaluate the nutritive value of wheat-bas ed thin stillage as a fluid source for ruminants. In vitro CP degradability of thin stillage was estimated relative to canola meal and heated canola m eal in a completely randomized design. Four ruminally cannulated steers wer e used in a double cross-over design to determine the effects of consuming thin stillstge or water as drinking sources on ruminal fermentation traits. The in vitro CP degradability of thin stillage (55.4%) was lower (P < .05) than that of canola meal (59.4%) and higher than that of heated canola mea l (31.6%). Ruminal pH for steers consuming thin stillage was higher (P < .0 5) at 1000 and 1100 and lower (P < .05) at 1900 and 2000 than that for stee rs consuming water. Total VFA followed a pattern that was the reverse of th at reported for pH. Ruminal NH3 N levels were higher (P < .05) for steers f ed thin stillage than for water-fed steers through most of the collection p eriod. Ruminal fluid and particulate matter passage rates were not affected by treatment and averaged .165 and .06 /h, respectively. The amount of thi n stillage and water that did not equilibrate with the ruminal fluid and, t hus, was considered to bypass the rumen was estimated to be 51.9 and 59.2% of total fluid consumed, respectively. Feeding wheat-based thin stillage ha d no adverse effects on ruminal metabolism.