Author
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VAREL V H - 5438-01-07 |
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KREIKEMEIER K K - 5438-01-07 |
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Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/3/1994 Publication Date: N/A Citation: N/A Interpretive Summary: Cattle are able to digest poor quality forages (low protein, mature) to a lesser extent than high quality forages. Thus, any improvements in digestibility of low quality forages should improve animal production efficiency. Studies with Amaferm, a fungal extract from Aspergillus oryzae, have shown that by an unknown mechanism, it will increase the bacterial populations in the rumen of cattle and improve the digestibility of poor quality forages. Our studies indicated that Amaferm increased bacterial populations and increased the rate of fiber digestion of poor quality bromegrass hay. However, even with these positive effects we did not see an increase in efficiency of animal production. The amount of fiber degraded ruminally was not increased, feed intake was not increased, and we did not improve microbial protein flow to the lower digestive tract. Amaferm had no effect on alfalfa hay which was of higher quality than the brome. More studies are needed to determine whether or not feeding higher concentrations of Amaferm than 3 g per cow daily, fed in this study, will improve feed intake and growth efficiency. Technical Abstract: Daily additions of 3 g Amaferm to alfalfa and bromegrass diets were evaluated for effects on ruminal and postruminal fiber and organic matter degradation, fermentation profile and bacterial nitrogen flow. Eight beef cows were fitted with ruminal and duodenal cannulae. Two experiments were conducted. Eight cows were fed bromegrass hay, 4 received Amaferm and 4 served as controls; later, eight cows received alfalfa hay with 4 receiving Amaferm and 4 serving as controls. Each experiment consisted of 28 d; 1 to 14 d for adaptation, 15 to 21 d for feed intake and 22 to 28 d for ruminal and duodenal sampling. Dacron bags containing NDF substrate from alfalfa or bromegrass were used to determine ruminal fiber degradation at 3,6,9,12,24,48, and 72 h. These data indicated that Amaferm increased degradation of the NDF, and hemicellulose when bromegrass was fed, but not when alfalfa was fed. There were no Amaferm effects on ruminal VFA, pH, ammonia or feed intake with cows fed either forage. Results from duodenal digesta and fecal sample analyses indicated that there were no effects of Amaferm on site or extent of organic matter or fiber digestion, or nitrogen flow in cows fed either brome or alfalfa. Amaferm increased the number of ruminal anaerobic bacteria in cows fed bromegrass but not in those fed alfalfa. Amaferm did not affect the total number of cellulolytic bacteria in cows fed either diet; however, with cows receiving bromegrass, Amaferm increased the proportion of Ruminococcus albus isolates from 21.7 to 33.3% of the total cellulolytics. Results indicate that Amaferm increased ruminal degradation of brome hay but these effects did not impact fiber utilization nor did it effect microbial protein synthesis. |
