Wet Maize Research Articles

Assessment of the Traditional Processing Methods in the Reduction of Aflatoxin Levels in Maize and Maize Products in Kenya

Aflatoxins are fungal secondary toxic metabolites produced predominantly by certain strains of the Aspergillus molds. The objective of this study was to investigate the effectiveness of Kenyan traditional processing methods in reduction of aflatoxin in maize. The traditional methods used included; alkaline cooking using Magadi soda and maize cob ash, decortication by pounding wet maize with mortar and pestle, dehulling in mechanical mill and exposure to solar radiation. Standardization of alkali cooking was done before actual treatment of the contaminated samples. Naturally contaminated samples of maize were sampled and used in the experiment. Aflatoxin analysis before and after each of the treatments was done using ELISA method and total aflatoxins expressed in parts per billion (ppb) (dry weight basis). The results were subjected to statistical analysis at 5% significance levels (p≤0.05). The reduction of aflatoxin was found to be highest when maize was boiled in maize cob ash solution which resulted in loss of aflatoxin from 83.1±0.3 ppb to 7.0±3.9 ppb. Dry decortication reduced aflatoxin from 51.3±15.3 to 9.6±0.8 ppb, boiling in Magadi soda led to a drop from 59.5±3.818 ppb to 13.4±0.424 ppb, solar irradiation caused a drop from 60.8±1.8 ppb to 13.7±0.1 ppb and pounding in Magadi soda resulted in least loss of aflatoxin from 81.5±0.3 to 72.7±0.2ppb. Aflatoxin loss in all the treatments was significant except for dry decortication. Only dry decortication and boiling in maize cob ash solution brought down the aflatoxin levels to below the maximum allowable limit as set by the Kenya Bureau of Standards (10ppb)

Hermetic Bags: A Short-Term Solution to Preserve High-Moisture Maize during Grain Drying.

Maintaining maize quality while drying during a rainy season is a major challenge for smallholder farmers in developing countries. We conducted a study to evaluate the impact of temporarily storing wet maize of 18, 21, and 24% moisture content (m.c.) in hermetic Purdue Improved Crop Storage (PICS) and polypropylene (PP) woven (control) bags for 21 days. Oxygen and carbon dioxide concentrations were monitored, and m.c., germination, and visual mold were assessed. In PICS bags, oxygen dropped below 1% within 7, 11.5, and 21 days for maize at 24, 21, and 18% m.c., respectively. After 21 days, the m.c. of maize stored in PICS bags remained constant, but decreased in PP bags. Germination of maize in PICS bags decreased by 0.5, 6.2, and 95.5 percentage points for 18, 21, and 24% m.c., respectively. In PP bags, germination decreased by 17.5, 15.2, and 39.5 percentage points for the respective moisture levels. After 21 days of storage, visible mold was present on maize stored in PP bags at both 21 and 24% m.c. No mold was observed on maize stored in PICS bags, but a fermentation smell was released from maize at 21 and 24% m.c. The results indicate that maize can be effectively stored in PICS bags at 21% m.c. or below for 21 days with minimal germination loss or mold growth. These findings highlight the potential of using hermetic bags for short-term grain quality preservation just before and during drying. This new utility adds to the current use of hermetic bags for protection against pests during long-term storage. Hermetic bags' dual functionality could significantly improve postharvest management on smallholder farms, thereby enhancing food and nutritional security and safety. Field testing is required in order to integrate this approach under smallholder farmers' conditions (e.g., temperature, m.c., drying practices, etc.).

Short-Term Hermetic Storage of Wet Maize and Its Effect on Quality.

Maize is a major crop grown in many regions of the world for human consumption, starch production, and animal feed. After harvest, maize is dried to avoid spoilage caused by fungal growth. However, in the humid tropics, drying maize harvested during the rainy season poses challenges. In such instances, temporary storing maize under hermetic conditions may preserve grain quality while waiting for conditions suitable for drying. Wet maize at the moisture contents (m.c.) of 18, 21, and 24% was stored for up to 21 days in both hermetic and non-hermetic jars. The stored maize was assessed, every 7 days, for germination and related parameters, presence of visible mold, and pH. After 21 days of storage at 18, 21, and 24% m.c., maize germination decreased by 28.5, 25.2, and 95.5 percentage points, respectively, in hermetic jars; and by 28.5, 25.2, and 94.5 percentage points in non-hermetic jars (control). There was visible mold on maize stored in non-hermetic jars after 21 days regardless of m.c. Maize at 21 and 24% m.c. stored in hermetic conditions underwent lactic acid fermentation that reduced the pH. The findings suggest that maize at 18 and 21% m.c. can be stored for 14 and 7 days, respectively, under hermetic conditions without significant loss of quality. Further research is needed to thoroughly assess the application of these findings for temporarily storing and subsequently drying maize on farms and along the grain value chain.

Solubility and swelling of soils from native starch

SummaryThe cleaning of food processing plants is essential for ensuring compliance with quality and hygiene standards. Properties of food‐borne soils such as solubility and swelling are relevant and provide information concerning their cleanability. In the context of cleaning processes in food industry, the aim of this study was to determine the impact that different cleaning fluids exhibit on the solubility and swelling behaviour of soils consisting of amylose‐ rich native maize, wheat, rice or potato starch or amylopectin rich native waxy maize starch. For this purpose, a process for the preparation of starch pastepowder, mimicking starch soils, was developed. After swelling in water or 20 g kg−1 NaOH at 25 or 55 °C, the solubility and the water binding capacity (WBC) of the starch powders were determined. The solubility of amylose rich starch paste powders was significantly higher in NaOH, whereas amylopectin rich waxy maize starch paste powder dissolved significantly better in water. The use of NaOH resulted in a significant decrease of the WBC of most starches. While a higher solubility and WBC was found for wet maize starch soils (starch paste) than for dried maize starch soils (starch paste powder), solubility and swelling of waxy maize starch soils were not affected by the residual moisture.

A Preliminary Study of Chemically Preserved and High-Moisture Whole Maize (Zea mays L.) Usage in Pekin Duck Nutrition: Effect on Growth Performance and Selected Internal Organ Traits.

Simple SummaryHarvested maize grains characterized by high moisture require the use of additional preservation processes to secure against the microbiota. The most commonly used practice is heat-drying, which is energy- and cost-consuming, as well as environmentally unfriendly. Thus, there is a need to omit these harmful techniques and evaluate the usage of wet maize in animal nutrition. The present study aimed to investigate the effect of the chemically preserved, high-moisture whole maize grain addition in Pekin duck nutrition on their growth performance and selected internal organ and gastrointestinal tract measurements and digesta pH values. The results of the experiment clearly showed that there is a possibility to partially replace commonly used heat-dry maize with the preserved whole-grain form without an adverse effect on the birds’ performances and selected organ morphometrical parameters. However, due to surprising changes in the pH values in the gizzard and caeca, further investigations, including microbiota analyses, are recommended.This study aimed to investigate the effect of chemically preserved, high-moisture whole maize grain addition in Pekin duck diets on their growth performance and selected internal organ and gastrointestinal tract measurements and digesta pH values. A total of 300 29-d-old male Pekin ducks were randomly distributed into three dietary treatments using five replicate pens per group and 20 birds per pen. The following treatment groups were applied: CON—basal diet, 5HM—5% of high-moisture, chemically preserved whole maize (HM) inclusion, and 10HM—10% of HM addition. The experiment lasted 21 d. The implementation of 5HM or 10HM did not affect (p > 0.05) the growth performance parameters, selected internal organ weights, and the gastrointestinal tract segment weights and lengths. However, significant changes in terms of the gizzard (p = 0.005), ileum (p = 0.030), and caecal (p < 0.001) digesta pH were observed, especially in the case of the 10HM group, which exhibited the greatest increase in pH in the gizzard and caecal digesta and decrease in the ileal digesta pH. The implementation of whole wet maize may be used in waterfowl diets from 29 d of age. Additionally, chemical preservation can efficiently reduce the cost of maize preparation in duck nutrition.

Experimental investigation of suitable thin layer drying curve to solar maize dryer assisted for biomass back-up heater

A solar dryer assisted by biomass back-up heater was designed and manufactured from locally available materials to dry maize, and the drying model is selected, which better fits the dryer test results. This study tried to address the problem associated with the fact that solar dryers are efficiently operational only when there is sufficient solar energy. The dyer comprises a solar air heater, drying chamber, biomass back-up heater, and airflow systems. The solar heater has a length and width of 2 m × 1 m respectively and is enclosed with a transparent glass that allows the solar energy into the collector. The measurement taken to evaluate this dryer's performance is temperature, moisture content, solar irradiation, and airspeed. The average temperature difference between the ambient and the collector outlet was recorded as 9.6 °C, and 12.8 °C in the solar and biomass assisted dryer. The daily average solar insolation for the test periods of October and December at the site was 673 W/m2. When the system is loaded with 50 kg of wet maize grain at an initial moisture content of 21.3% and dried to 14.4% moisture content in 45 h drying time in the solar dryer, 4.03 kg of moisture is removed. A 50 kg of wet maize grain at an initial moisture content of 22.9% and dried to 14.2% moisture content in 27 h in solar dryer assisted by biomass back-up heater, 5.06 kg of moisture is removed. Solar dryer collector efficiency was estimated as 64.2% with an average drying rate of 0.0746 kg/hr. The solar dryer system efficiency was 20.8%, and solar assisted dryer efficiency was 4.3%.

The effectiveness of the use of probiotics for wet maize grain preserving

The process of processing and storage of high moisture grain is one of the important problems of forage production, especially in the Carpathian region due to its excessive moisture, therefore, due to the intensification of the livestock industry, the conservation of feed is becoming increasingly important. The purpose of the research was to determine the effect of different doses of bacterial preparation KT-L 18/1 (produced by Chernihiv ISMAV NAAS) on the preservation of nutrients and microbiological parameters of maize grain of high humidity in dynamics. The investigation of influence different doses of bacterial preparation KT-L 18/1 on the nutrients and microbiological parameters protection in maize grain with high humidity were realized in the laboratory of animal feed and feed technology (containers with maize grain, treated with different doses of microbial preparation KT-L 18/1, were laid, their chemical composition and microbiological parameters were determined). The control was grain without drying and with the addition of a chemical preservative CAS. During storage of treated maize grain were determined their chemical composition, content of main fermentation acids, and microbiological parameters. It was found that dry matter reduce, an integral feed nutrition indicator, in maize grain samples, treated with KT-L-18/1 and chemical preservative were 1.0 and 1.1% respectively. The lowest number of harmful micromycetes was noted by using the KT-L-18/1 at dose 8 ml/kg. It was found that using of chemical preservative CAS suppresses all investigated microorganisms, including lactic acid bacteria. Probiotic preparation KT-L-18/1 at dose 8 ml/kg wet maize grain provides to nutrients preservation same level like chemical preservative through active development of lactic acid microorganisms. It is advisable for final conclusions to carry out the testing of this preparation during the harvesting of wet ivy corn grain under production conditions and in experiments on animals.

Sustaining crop productivity while reducing environmental nitrogen losses in the subtropical wheat-maize cropping systems: A comprehensive case study of nitrogen cycling and balance

Balancing the nitrogen (N) budgets of agricultural systems is essential for sustaining yields at lower environmental costs. However, it is still rare to find reports on the total N budgets of agricultural systems including all N fluxes in the literature. Here, we conducted a comprehensive study on the effects of different N fertilizers (control, synthetic fertilizer, 60% synthetic fertilizer N plus 40% pig manure N, pig manure N applied at the same rate of 280kgNha−1 yr−1) on N pools, cycling processes, fluxes and total N balances in a subtropical wheat-maize rotation system in China by monitoring in situ N fluxes combined with field 15N-tracer and 15N isotope-dilution techniques. The warm and wet maize season was associated with significantly larger N losses via gaseous and hydrological pathways than the cooler and drier wheat season. Nitrate leaching and NH3 volatilization were the main N loss pathways, accounting for 78% and 93% of the annual hydrological and gaseous N losses, respectively. The field 15N tracing experiment showed that the wheat system had a high N retention capacity (∼50% of 15N application), although the N residence time was short. In the subsequent maize season, 90% of the residual 15N-labeled fertilizer in the soil that had been applied to the wheat system was utilized by plants or lost to the environment. The combined application of synthetic and organic fertilizers (pig manure) or application of pig manure resulted in significantly higher soil N retention and lower NO3− leaching, while yields remained unaffected. However, the application of manure resulted in larger NH3 volatilization losses compared with the application of synthetic fertilizer alone. Thus, our study suggests that a combination of synthetic and organic N fertilizers is suitable for sustaining agricultural productivity while reducing environmental N losses by fostering interactions between the soil C and N cycles.

Effects of moisture content or particle size on the in situ degradability of maize silage and alfalfa haylage in lactating dairy cows.

A study using four Holstein cows with ruminal cannulas was conducted to evaluate the degradability of different moisture content or particle size of maize silage and alfalfa haylage. The maize silage (MS; 20-mm length) and alfalfa haylage (AH; 40-mm length) samples were wet (wet maize silage, MSW; wet alfalfa haylage, AHW), dried (dried maize silage, MSD; dried alfalfa haylage, AHD), or ground to pass through a 2.5-mm screen (dried ground maize silage, MSG; dried ground alfalfa haylage, AHG). Samples were incubated in the rumen for 2, 6, 12, 24, 36, 48, and 72 h. Cows were fed ad libitum and allowed free access to water. High moisture content treatment of MSW expressed a lower rinsing NDF and ADF degradability at 2 h (P < 0.05) compared with dried samples (MSD and MSG). Different moisture content and particle size had a significant impact (P < 0.05) on the NDF degradability at 72 h, ADF degradability at 36, 48, and 72 h, and ruminally degradable ADF. All of the highest values were observed in small particle size and low moisture content AHG treatment. Based on this study, sample processing, such as drying and grinding, should be considered when evaluating nutritive values of forages.

Effects of maize conservation techniques on the apparent total tract nutrient and mineral digestibility and microbial metabolites in the faeces of growing pigs

A digestibility trial was conducted to investigate the effects of different maize conservation techniques on the nutrient digestibility of a commercial maize–soybean meal diet fed to growing pigs. The influence on the content of biogenic amines, volatile fatty acids (VFAs) and ammonia in the faeces was also determined. Maize was either dried (dried maize), ensiled after milling (maize silage) or tight-closed-stored (TCS-maize) as a whole grain. Nine growing pigs (35.1±0.8kg) were used in a 3×3 Latin square experiment. They were fed diets based on the different maize conserves, barley and soybean meal to ensure the same content of N, energy and digestible phosphorus (P) in the diet. The apparent total tract digestibility (ATTD) of the DM, ash and starch was improved (P<0.05), and the ATTD of the ether extract tended to be improved (P<0.10) when the maize was fermented. Moreover, based on the results related to the ATTD of P in the different maize conserves of a previous study, less P was added to diets that were based on fermented maize. Nevertheless, the P excretion was reduced without compromising P utilisation. The metabolic products of the gut microorganisms, biogenic amines and most VFAs in the faeces were reduced when the animals were fed fermented maize (P<0.05). The observed effects were more pronounced in the maize silage treatment. In conclusion, the current data suggest that the air-proofed storage of wet maize can be a strategy to improve the feeding value of maize-based diets fed to pigs.

Processing maize flour and corn meal food products

Corn is the cereal with the highest production worldwide and is used for human consumption, livestock feed, and fuel. Various food technologies are currently used for processing industrially produced maize flours and corn meals in different parts of the world to obtain precooked refined maize flour, dehydrated nixtamalized flour, fermented maize flours, and other maize products. These products have different intrinsic vitamin and mineral contents, and their processing follows different pathways from raw grain to the consumer final product, which entail changes in nutrient composition. Dry maize mechanical processing creates whole or fractionated products, separated by anatomical features such as bran, germ, and endosperm. Wet maize processing separates by chemical compound classification such as starch and protein. Various industrial processes, including whole grain, dry milling fractionation, and nixtamalization, are described. Vitamin and mineral losses during processing are identified and the nutritional impacts outlined. Also discussed are the vitamin and mineral contents of corn.

Design parameters for a small-scale batch in-bin maize dryer

Early season maize is harvested with high moisture content that makes it impossible to store. The sale of early season maize in green form is uneconomical to the farmer. Experience had shown that farmers could hardly make the cost of production from their sales. Also, grain losses are high when maize is harvested green. To minimize grain losses and thereby increase value and the profit margin of the farmer, a grain dryer is necessary for wet grains. Therefore, this paper presents the design and development of a batch in-bin maize grain dryer. Some properties of maize such as moisture content and bulk density were determined to get information required for design of the dryer. The dimension of drying chamber, amount of moisture to be removed in a batch, quantity of air required to effect drying, volume of air required to effect drying, blower capacity, quantity of heat required to effect drying and actual heat used to effect drying were all designed for. A maize dryer was developed with a batch size of100 kg of threshed wet maize. The dryer can be used in laboratory for experimental purpose as well as on the farm for commercial purposes. The dryer can be used to measure drying rates of maize at different initial moisture contents, drying air temperatures, drying air velocities and grain beds. The effects of different drying temperature, air velocity, loading and agitating speed on the quality of dried maize can be investigated with the dryer.

High-energy forage feeding diets and body condition on the finishing of cull dairy cows

Combinations of two high-energy forage finishing diets and two initial body condition scores (BCSs) in a 2 × 2 factorial experimental design were evaluated on cull Holstein–Friesian (HF) cows to improve animal performance and carcass characteristics, aimed at achieving proper fatness and conformation scores (a minimum of ‘4’ and ‘O’, respectively) required for the marketing of high-value loin steaks. The two finishing diets were (i) conventional maize silage complemented with concentrate diet and (ii) wet maize ear silage (pastone) complemented with dry-herbage diet. The two initial body condition levels were (i) low BCS < 5 (LBCS) and (ii) high BCS > 5 (HBCS). The HBCS animals had the greatest potential to respond to the finishing diets. They needed a smaller total feed intake (TFI) and a shorter finishing period (FP) to meet the marketing requirements. The average feed budgets necessary to finish cull dairy cows and to achieve the minimum scores ‘4’ and ‘O’ of carcass classification were 2.31 and 3.61 t of dry matter (DM)/cow for HBCS and LBCS animals, respectively, while the FP lasted an average of 143 and 224 days for HBCS and LBCS animals, respectively. With regard to the two feeding diets, we found no differences for TFI, carcass characteristics and loin muscle features, such as weight, diameter and intramuscular fat.

Improved Nitrogen Management for an Intensive Winter Wheat/Summer Maize Double‐cropping System

Improving N and straw management to achieve high crop yields, minimize nitrate leaching, and balance soil fertility presents challenges in winter wheat (Triticum aestivum L.)/summer maize (Zea mays L.) double cropping systems on the North China Plain. A long‐term field experiment was designed to study crop performance, nitrate leaching, and N balance under three N management approaches (conventional farming practice, improved Nmin, and N balance methods) with two straw management options (straw removal and return), and two types of organic amendment (cattle [Bos taurus] manure and municipal waste compost). Grain and straw yields and C/N ratios were determined in each crop, together with N uptake and residual NO3–N in the top 2 m of the soil profile. Over six successive crops of the study (October 2006–September 2009) 32 to 93% of applied N was saved without reducing either wheat or maize yields and less NO3–N accumulated in the top 1 m of the soil (the root zone) or leached 1 to 2 m down the soil profile when the two new N management approaches were used in comparison with conventional N management. Straw return did not affect crop yield or NO3–N accumulation but the N rate with straw return in the improved Nmin method increased due to N immobilization induced by the straw. Moreover, in the hot and wet maize seasons, chemical fertilizer N rate in the N balance method can further decrease by reducing the target residual NO3–N in the 0 to 1 m root zone and by increasing the percentage availability of total N in organic amendments in future studies.

Investigation of the maize ear threshing process

Wet maize ears of the ‘Benicia’ variety with a moisture content of 32.5% and medium dry maize ears of ‘Attribut’ variety with a moisture content of 18.5% were fed in parallel and perpendicular to the drum shaft of a conventional threshing drum. Maize ears fed in parallel with the drum shaft in the concave clearance moved twice as fast (4–5 m s −1 ), received twice as few (5–7) rasp bar impacts, and 10–20% of the threshed grain passed through the concave when compared to threshing with the maize ears fed perpendicular to the drum shaft. Threshing losses of wet ‘Benicia’ maize ears did not exceed the permissible range of 0.5% when drum rasp bars moved at the speed of 16 m s −1 and the concave clearance was in the front 21 mm and at the end 6 mm (21–6 mm). When medium dry ‘Attribut’ maize ears were threshed, the concave clearance was in the front 27 mm and at the end 15 mm. When maize ears were fed perpendicular to the drum shaft, the clearance could be increased by 2 mm as the maize ears moved through the concave at an approximately 1.8 m s −1 slower speed, and received 8 additional rasp bar impacts. During the threshing of wet ‘Benicia’ maize ears the threshing damage was 30% greater as compared with the threshing damage of medium dry maize ears of ‘Attribut’ variety. Wet maize should be immediately crushed and preserved as silage.

Case–Control Study of an Acute Aflatoxicosis Outbreak, Kenya, 2004

Objectives: During January–June 2004, an aflatoxicosis outbreak in eastern Kenya resulted in 317 cases and 125 deaths. We conducted a case–control study to identify risk factors for contamination of implicated maize and, for the first time, quantitated biomarkers associated with acute aflatoxicosis.Design: We administered questionnaires regarding maize storage and consumption and obtained maize and blood samples from participants.Participants: We recruited 40 case-patients with aflatoxicosis and 80 randomly selected controls to participate in this study.Evaluations/Measurements: We analyzed maize for total aflatoxins and serum for aflatoxin B1–lysine albumin adducts and hepatitis B surface antigen. We used regression and survival analyses to explore the relationship between aflatoxins, maize consumption, hepatitis B surface antigen, and case status.Results: Homegrown (not commercial) maize kernels from case households had higher concentrations of aflatoxins than did kernels from control households [geometric mean (GM) = 354.53 ppb vs. 44.14 ppb; p = 0.04]. Serum adduct concentrations were associated with time from jaundice to death [adjusted hazard ratio = 1.3; 95% confidence interval (CI), 1.04–1.6]. Case patients had positive hepatitis B titers [odds ratio (OR) = 9.8; 95% CI, 1.5–63.1] more often than controls. Case patients stored wet maize (OR = 3.5; 95% CI, 1.2–10.3) inside their homes (OR = 12.0; 95% CI, 1.5–95.7) rather than in granaries more often than did controls.Conclusion: Aflatoxin concentrations in maize, serum aflatoxin B1–lysine adduct concentrations, and positive hepatitis B surface antigen titers were all associated with case status.Relevance: The novel methods and risk factors described may help health officials prevent future outbreaks of aflatoxicosis.

Effect of phosphine (ph3) in controlling aflatoxin production in stored groundnut (Arachis hypogea) and wet maize (Zeamais)

The potentials of phosphine in controlling aflatoxin production by Aspergillus flavus on groundnut and wet maize stored in seaied containers under ambient conditions in the laboratory were studied. Groundnut and wet maize inoculated with spore suspensions of A. flavus and exposed to phosphine in sealed containers for toxin production had a very low mold counts and an aflatoxin B1 of less than 5 mg/kg during 6 months storage. The grains remained fresh without loss in quality at the end of storage. Similarly treated groundnut and wet maize stored in air in sealed containers had a very high mold count and aflatoxin B1 contents within 10 and 2 days, respectively. The results of the study will be useful in post-harvest handling of damp grains in the humid zone where the harvesting period of maize coincides with the wet season.

各種包材によるタイメイズのAspergillus flavusおよびアフラトキシン汚染防止

Each 10kg of high moisture maize kernels (moisture content (mc) 29.1%) inoculated with Aspergillus flavus was packed in various kinds of package. Every bag was sealed with string so as to make the air space to be as little as possible. In traditional jute bag and fabricated polypropylene (PP) bag, A. flavus infection occurred completely within 4 to 6 days. Thick polyethylene (PE) bag (125μm thick) and high density PE bag (40μm thick) perfectly in hibited the growth of A, fiavus for over 20 days and no aflatoxin was detected. Wet maize kernels with various maturity levels and mc (97 to 125 days after planting and mc 21.3% to 33.4%) were also prevented from A. flavus infection completely in the thick PE bag.

Systems of utilizing maize stover for feeding growing cattle

Systems analysis techniques were used to compare two selected maize stover systems with a conventional maize silage system for growing beef cattle. All systems were based on a 200 ha integrated farm currently utilizing 160 ha for a cash crop grain maize enterprise and 40 ha of maize silage for a cattle growing operation. The conventional maize silage system fed 423 cattle for an average gain of 160 kg liveweight per animal. Alternative systems fed an equal number of cattle and produced an equal gain per animal. One alternative (ammoniated system) involved harvesting wet maize stover with a forage harvester immediately after grain maize harvest and subsequent treatment with ammonia (4% dry matter basis) at storage. A second alternative (separated system) was designed to harvest and store mature whole-plant maize silage (50–55% H 2O) followed by separation into grain and stover fractions at feeding time. Cost per steer for the growing period was calculated using a cost simulation model for each system. The separated system had a lower mean cost per steer, while the ammoniated system had a slightly higher cost per steer than the conventional maize silage system, Can. $189, Can. $197 and Can. $195, respectively. Break-even shelled maize prices, representing the shelled maize price at which each alternative system had an equivalent cost per steer to the conventional system, were calculated. Break-even shelled maize prices were Can. $122 and Can. $140 t −1 for the separated stover and ammoniated stover systems, respectively. The estimated reduction in cost per steer would appear to make the separated stover system feasible even at moderate shelled maize prices.