INFLUENCE OF FEEDING ASPERGILLUS-ORYZAE FERMENTATION EXTRACT (AMAFERM) ON IN-SITU FIBER DEGRADATION, RUMINAL FERMENTATION, AND MICROBIAL PROTEIN-SYNTHESIS IN NONLACTATING COWS FED ALFALFA OR BROMEGRASS HAY

Daily additions of 3 g of Amaferm to alfalfa (13% CP) and bromegrass ( 6% CP) diets were evaluated for effects on ruminal and postruminal fib er and organic matter digestion, fermentation profile, and duodenal ba cterial nitrogen flow. Eight beef cows were fitted with ruminal and du odenal cannulas. Two experiments were conducted. Eight cows were fed b romegrass hay, four received Amaferm and four served as controls; late r, seven cows received alfalfa hay with three receiving Amaferm and fo ur serving as controls. Each experiment lasted 28 d: d 1 to 14 for ada ptation, d 15 to 21 for measurement of feed intake, and d 22 to 28 for ruminal and duodenal sampling. Dacron bags containing NDF substrate f rom alfalfa or bromegrass were used to determine ruminal fiber degrada tion at 3, 6, 9, 12, 24, 48, and 72 h. There were no Amaferm effects ( P > .15) on rate or extent of fiber degradation in situ when bromegras s or alfalfa was fed. There were no Amaferm effects (P > .10) on conce ntrations or molar proportions of ruminal VFA, pH, or NH3 or on feed i ntake in either experiment. There were no effects (P > .10) of Amaferm on site or extent of organic matter or fiber digestion, or duodenal n itrogen flow in cows fed either bromegrass or alfalfa. Amaferm increas ed (P < .10) the number of ruminal anaerobic bacteria in cows fed brom egrass but not in those fed alfalfa. Amaferm did not affect (P > .10) the total number of cellulolytic bacteria in cows fed either diet; how ever, for cows that received bromegrass, Amaferm increased (P < .02) t he proportion of Ruminococcus albus isolates from 21.7 to 33.3% of the total cellulolytics. Results indicate that Amaferm increased the numb er of total ruminal anaerobes when brome hay was fed; however, no affe ct on microbial protein synthesis or rate and extent of fiber degradat ion occurred.