| Abstract | Within the South African feedlot industry, there are currently several different roughage sources available for use in feedlot finishing diets. To evaluate the influence of dietary energy and fibre source on rumen function in feedlot animals, four roughage sources (wheat straw, Eragrostis curvula hay, cottonseed hulls and maize silage) were used in combination with hominy chop or dry rolled maize in two experiments. Four Beefmaster steers (270kg �15kg) fitted with ruminal cannulae were used in two separate experiments in a 4 x 4 Latin square design. Experiment 1 was conducted to evaluate each roughage source in combination with hominy chop namely: wheat straw, hominy chop (WSHC); Eragrostis hay, hominy chop (EHHC); cottonseed hulls, hominy chop (CHHC); and maize silage, hominy chop (MSHC). Experiment 2 was conducted to evaluate each roughage source in combination with dry rolled maize (DRM) namely: wheat straw, dry rolled maize (WSDRM); Eragrostis curvula hay, dry rolled maize (EHDRM); cottonseed hulls, dry rolled maize (CHDRM); and maize silage, dry rolled maize (MSDRM). Diets were designed to contain equal amounts of energy, starch, crude protein, neutral detergent fibre (NDF) and 7.5% roughage source in both experiments. All diets were evaluated for particle size distribution through the Penn State Forage Particle Separator (PSPS) and ruminal fermentation parameters (volatile fatty acid composition, VFA; rumen ammonia nitrogen, NH3-N; lactate and ruminal pH) were compared for each experiment. Results from experiment 1 showed that animals fed the MSHC had the lowest (P3-N concentrations did not differ but lactate concentrations were higher for EHDRM when compared to the MSDRM and WSDRM diets (P>0.05). Ruminal pH observations showed steers consuming the MSDRM diet to have the lowest mean ruminal pH of 5.53 which differed (P
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Please cite as follows:
Vermaak, HJ 2011, Effect of dietary energy and fibre source on rumen function in feedlot
steers, MSc(Agric) dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-11182011-115955
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