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ABSTRACT

Chlorella sorokiniana CS-01, UTEX 1230 and UTEX 2714 were maintained in 10% anaerobic digester effluent (ADE) from cattle manure digestion and compared with algal cultivation in Bold's Basal Medium (BBM). Biomass of CS-01 and UTEX 1230 in ADE produced similar or greater than 280mg/L after 21days in BBM, however, UTEX 2714 growth in ADE was suppressed by more than 50% demonstrating a significant species bias to synthetic compared to organic waste-based media. The highest accumulation of protein and starch was exhibited in UTEX 1230 in ADE yielding 34% and 23% ash free dry weight (AFDW), respectively, though fatty acid methyl ester total lipid measured less than 12% AFDW. Results suggest that biomass from UTEX 1230 in ADE may serve as a candidate alga and growth system combination sustainable for animal feed production considering high yields of protein, starch and low lipid accumulation.

Long-term responses of pasture plant species to management strategies that vary amount and form of N inputs form a knowledge gap. Our objective was to determine how supplementation of grazing beef cattle (Bos taurus) with corn (Zea mays L.) dried distillers grains plus solubles (DDGS) in unfertilized pasture (SUPP) aff ects annual herbage accumulation and presence of plant species and functional groups relative to unsupplemented beef cattle on unfertilized (CONT) and N-fertilized (FERT) smooth bromegrass (Bromus inermis Leyss.) pasture. We addressed this objective in the sixth (2010) and seventh (2011) years of a long-term experiment in eastern Nebraska, where N input from DDGS supplementation and urea fertilizer averaged 0, 43, and 90 kg ha -1 yr -1 within CONT, SUPP, and FERT, respectively. For these years, annual herbage accumulation averaged 6.87, 6.80, and 10.58 Mg ha -1 (LSD = 1.49) and 66.5, 66.2, and 76.0% of herbage accumulated by 25 June (LSD = 5.3) in CONT, SUPP, and FERT, respectively. Smooth bromegrass occurred in 99.8% of 0.1-m 2 pasture quadrats regardless of treatment. Cessation of N fertilizer input, however, increased presence of annual foxtail (Setaria spp.), annual graminoids, and annuals among quadrats in CONT relative to FERT. Supplementation of DDGS, while shown in previous studies to improve weight gains and N use efficiency in cattle, supplied enough N through excretion to provide an intermediate level of resistance to annual weeds. Nitrogen excreted from cattle supplemented with DDGS, however, did not aff ect herbage accumulation in subsequent years.

Cattle weights can be highly variable and are influenced by many factors, including time of weighing, ambient temperature, feed intake, and cattle handling. A protocol of limit feeding has been in use since the 1980s that was designed to reduce variation in gut fill due to differences in intakes. Cattle are penned and fed a 50% hay, 50% wet corn gluten feed or grain diet (DM basis) at an estimated 2% of BW for at least 5 d, after which weights are taken on 2 consecutive d and averaged for a limit-fed BW (LFW). For this analysis, full-fed weights (FFW) also were taken before the limit-feeding period while cattle had ad libitum intakes. Data from 18 experiments were used to analyze differences within 2-d LFW and between LFW and FFW. For 10 of the 18 experiments, FFW also were measured on 2 consecutive d. Cattle included in this summary were grazing cornstalks, smooth bromegrass pasture, Bermuda grass pasture, fescue pasture, native range, or in a dry lot on a 70% forage diet. The largest differences between FFW and LFW for individual cattle were -39 to +44 kg over all 18 experiments. Differences between 2 consecutive d of LFW were -23 to +24 kg for all 18 experiments. Differences between 2 d of FFW were -14 to +34 kg in the 10 experiments measuring FFW on 2 consecutive d. There was not a clear relationship between FFW and LFW; each weighing scenario had unique environmental conditions that led to different relationships. Differences in both beginning and ending BW were compounded when calculating ADG. Average daily gain was calculated for 15 of the experiments on the basis of either LFW or FFW. Differences between LFW and FFW ADG were -0.29 to +0.31 kg/d. The maximum ADG based on FFW was 1.62 kg/d. This large ADG, on a forage based diet, was likely due to changes in gut fill rather than tissue gain. These data suggest that handling cattle in a similar manner when weighing is more important than limiting intakes to decrease variance between weights. However, limiting intake before collection of beginning and ending BW better estimates empty body weight of cattle, allowing for a more accurate determination of actual body tissue weight gain. Measuring weights accurately becomes especially crucial when evaluating multiple components within a system (e.g., cornstalks to pasture to feedlot). Feeding a standard diet between these components of the system minimizes differences in gut fill due to treatment and allows for a more accurate determination of each component's contribution to the total system.

Increased corn prices over the past decade have altered land use away from traditional forage in favor of corn. Accordingly, beef and dairy producers have had to adopt nontraditional forage resources into their production systems, many of which have become available as a result of increased corn production. Corn residues have become more available due to increases in corn hectares and yield. The individual plant components (i.e., husk, leaf, and stem) vary in fiber digestibility (NDF digestibility estimates = 40.5, 31.4, and 0.6% ± 0.8 for husk, leaf, and stalk, respectively). Stocking cattle to consume 3.6 kg forage/25.5 kg of grain allows cattle to graze selectively; selection of husks and leaves improves cattle performance. Byproducts of the wet and dry milling industries can be supplemented to calves grazing corn residues to provide protein and energy. Optimal gains were observed when these byproducts were supplemented at approximately 2.5 kg/d to 250-kg growing calves. Gestating beef cows do not require supplemental inputs when grazing corn residue, if stocked appropriately. Alkaline treatment of crop residues improves their feeding value. Concentrations of up to 20% harvested corn residue treated with calcium oxide can be included in finishing diets with an average of 1.3% reduction in G:F when diets contain 40% wet or modified distillers grains. Conversely, when untreated corn residues are included in similar finishing diets, G:F is reduced by 13.4%. Calcium oxide-treated residues included in beef growing diets increases DMI and ADG without significant improvements in G:F. Calcium oxide treatment of corn residues has been evaluated in dairy diets by replacing corn or corn silage with variable results. Efficient use of nontraditional fiber sources, such as corn milling byproducts and corn residue, are critical to the future viability of ruminant animal production.

Terry, "Effect of distillers grains moisture and inclusion level in livestock diets on greenhouse gas emissions in the corn-ethanollivestock life cycle" (2011