Stored Corn Research Articles

Effect of storage on the essential oil composition of Piper nigrum L. fruits of different ripening states.

The qualitative and quantitative composition of the essential oil from black, green, and white pepper was determined by using a simultaneous distillation and extraction micromethod for oil isolation and gas chromatography (GC)/flame ionization detection (FID) and GC/mass spectrometry (MS) analysis techniques. The most abundant compounds in pepper oils were (E)-beta-caryophyllene (1.4-70.4%), limonene (2.9-38.4%), beta-pinene (0.7-25.6%), Delta-3-carene (1.7-19.0%), sabinene (0-12.2%), alpha-pinene (0.3-10.4%), eugenol (0.1-41.0%), terpinen-4-ol (0-13.2%), hedycaryol (0-9.1%), beta-eudesmol (0-9.7%), and caryophyllene oxide (0.1-7.2%). Green pepper corn obtained by a sublimation drying method gave more oil (12.1 mg/g) and a much higher content of monoterpenes (84.2%) in the oil than air-dried green pepper corn (0.8 mg/g and 26.8%, respectively). The oil from ground black pepper contained more monoterpenes and less sesquiterprnes and oxygenated terpenoids as compared to green and white pepper oils. After 1 year of storage of pepper samples in a glass vessel at room temperature, the amount of the oils isolated decreased, the content of terpenes decreased, and the amount of oxygenated terpenoids increased. Differently from other pepper samples, 1 year storage of green pepper corn raised the oil amount more than twice of both drying methods.

N‐Fatty Acylation of Hydrolyzed Fumonisin B1, But Not of Intact Fumonisin B1, Strongly Enhances In Vitro Mammalian Toxicity

Fumonisin B1 (FB1) is the most abundant of a series of sphingosine‐analog mycotoxins produced by Fusarium verticillioides, the major fungal contaminant of stored corn (maize) world‐wide. Fumonisins were originally isolated as environmental tumor promoters, and they remain a concern because they are frequent contaminants of corn‐derived food products intended for direct human consumption. FB1 inhibits ceramide synthase, which may account for its acute toxic effects, but understanding of its tumor promotion mechanism has been limited by the general lack of understanding in the field. There is no evidence for functional metabolism of fumonisins in mammals, but abiogenic conversions during food processing are a concern because some known conversion products retain biological activity, including hydrolyzed FB1 (HFB1). HFB1, formed by alkaline removal of FB1 side chains, is a frequent contaminant of lime‐treated corn products such as tortillas and tortilla chips. Humpf et al. (J. Biol. Chem., 273, 19060, 1998) ...

Responses of Corcyra cephalonica (Stainton) to pirimiphos-methyl, spinosad, and combinations of pirimiphos-methyl and synergized pyrethrins.

Field control failures with pirimiphos-methyl against the rice moth, Corcyra cephalonica (Stainton), in Weslaco, Texas, USA, led us to investigate the susceptibility of this particular strain to pirimiphos-methyl, spinosad, pyrethrins synergized with piperonyl butoxide, and pirimiphos-methyl combined with synergized pyrethrins. In laboratory bioassays, 50 eggs of C cephalonica were exposed to untreated and insecticide-treated corn and sunflower seeds to determine larval survival after 21 days, egg-to-adult emergence after 49 days, and larval damage to seeds at both exposure periods. Pirimiphos-methyl at both 4 and 8 mg kg(-1) did not prevent larval survival or egg-to-adult emergence of C cephalonica on either corn or sunflower seeds, and seed damage was evident at both rates. The C cephalonica strain was highly susceptible to spinosad at 0.5 and 1 mg kg(-1). At both spinosad rates, reduction in larval survival, egg-to-adult emergence, and seed damage relative to the control treatment was > or = 93% on both corn and sunflower seeds. Pirimiphos-methyl and spinosad were generally more effective against C cephalonica on corn than sunflower seeds. The C cephalonica strain was completely controlled on corn treated with 1.5 mg kg(-1) of pyrethrins synergized with 15 mg kg(-1) of piperonyl butoxide. Many larvae survived and became adults on corn treated with synergized pyrethrins at < or = 0.75 mg kg(-1). Corn treated with pirimiphos-methyl at 4, 6 or 8 mg kg(-1) in combination with 0.38 to 1.5 mg kg(-1) of synergized pyrethrins reduced larval survival by > or = 95%, egg-to-adult emergence by > or = 97%, and seed damage by > or = 94%. Our results suggest that the C cephalonica strain can be controlled on corn by combining pirimiphos-methyl with synergized pyrethrins or with synergized pyrethrins at the labeled rate. Although spinosad is not currently labeled for use on stored corn and sunflower seeds, it appears to be effective against C cephalonica on both commodities at very low rates.

Correlation between the infestation level of Sitophilus zeamais Motschulsky, 1855 (Coleoptera, Curculionidae) and the quality factors of stored corn, Zea mays L. (Poaceae)

This experiment was carried out in order to evaluate the effect of Sitophilus zeamais on physical, physiological and sanitary quality of stored corn. Samples of 500 g of the hybrid OC-705, in three replicates, were conditioned in glasses covered with a screened lid, and kept in chamber at 25±2ºC, 70±5% RH and 12 h of photophase, for 150 days. The infestation levels were 0, 5, 15 and 50 adults/replicate, for the storage periods of 30, 60, 90, 120 and 150 days. The moisture content, classification, weight loss, germination and internal infestation were evaluated monthly. Significant inverse correlations were verified between the number of insects and both the germination and the weight loss; also between the internal infestation and the germination and the standard type. The presence of S. zeamais showed a positive correlation with the weight loss, what means that the internal and external infestations contribute to the reduction of physiological and physical quality of corn seeds. The mean dry matter loss was 0,36%/day, corresponding to a consumption of 0,0001%/insect/month. As the result of those damages, the product suffered reduction of the commercial grade in 30 days, with significant loss in all quality factors.

Fumonisins: Abiogenic Conversions of an Environmental Tumor Promoter and Common Food Contaminant

Fumonisins are a series of sphingosine‐analog mycotoxins produced by Fusarium verticillioides, a ubiquitous contaminant of stored corn (maize) world‐wide. Extensive alterations in the structures of fumonisins are possible without complete loss of in vitro toxicity. Numerous laboratories have reported that fumonisin B1 (FB1) levels in corn‐derived foods are reduced during roasting and frying. We have conducted radiotracer studies to determine the fate of tritium‐labeled FB1 added in laboratory models of corn flake manufacture (roasting), and tortilla chip manufacture (frying). These studies have confirmed that most, but not all, FB1 is converted to other substances during cooking. Under roasting conditions the major conversion pathway resulted in radiolabeled FB1 becoming covalently bound to proteins. Several lines of evidence supported a proposed role for FB1‐anhydride, an intermediate formed by loss of water from a FB1 side chain, which enabled the toxin to bind covalently to proteins by reacting with amino groups. Under nixtamalization/frying conditions in preheated cooking oil, both FB1 and hydrolyzed FB1 were efficiently N‐fatty acylated to the corresponding ceramide derivatives, presumably by fatty acid anhydrides or other degradation products formed from the fat by non‐oxidative thermal degradation. The N‐fatty acylated fumonisin derivatives were efficiently extracted from the chips into the hot oil. We will not understand the full threat to food safety posed by the fumonisins until we know what they are converted to during cooking, and what is the toxicity of those conversion products.

Post-harvest storage of corn: effect of beginning moisture content on mycoflora and fumonisin contamination

The effect of storage on mycoflora profile was monitored bimonthly in 36 corn (Zea mays L.) samples, dividing the same sample into groups dried to 11 and 14% moisture content (1008 analysis). These groups were further subdivided based on the initial total count (moulds and yeasts) up to 104 CFU g-1 (12 samples, range 1.6 × 104 to 9.0 × 104, mean 3.8 × 104 CFU g-1) and up to 105 CFU g-1 (24 samples, range 1.0 × 105 to 5.0 × 105, mean 2.7 × 105 CFU g-1). In the corn group dried to 11%, the fumonisin content was analysed at the initial stage (freshly harvested) and at the end of 12-month storage. Fusarium spp. and Penicillium spp. prevailed at the freshly harvested stage (100%), maintaining this profile throughout 12 months, in corn dried to both 11 and 14%. Cladosporium spp., Aspergillus spp. and Phoma spp. were also detected at lower frequencies during the storage. Fusarium spp. and the total fungal colony count during 12-month storage carried out with samples dried to 11 or 14% moisture content were statistically evaluated using ANOVA for randomized complete block design. The correlation between storage time and Fusarium spp. and total fungal colony count data was analysed by Pearson's correlation test. There was no difference in Fusarium spp. and total counts in the 104 CFU g-1 initial total count group throughout the storage time (p < 0.05). There was a negative correlation between fungal population and storage time (p < 0.05) in the 105 CFU g-1 initial total count group. Fumonisins were detected in all freshly harvested corn, at a mean concentration of 9.9 ± 6.0 µg g-1 (range 0.74-22.6 μg g-1). These values did not change in the 12-month stored corn (mean of 9.9 ± 5.8 μg g-1, range 0.81-23.7 μg g-1). These post harvest data indicated the importance of moisture content at the crop harvesting/predrying stage to control fungal growth and further fumonisin production.

SHELLED CORN CO2 EVOLUTION AND STORAGE TIME FOR 0.5% DRY MATTER LOSS

Following harvest, corn raised for grain is subject to infection and deterioration due to storage fungi. Laboratorystorage studies done on yellow dent corn in the 1960s established dry matter loss, as estimated by CO2 evolution duringstorage, to be a usable indicator of corn deterioration during storage. As a result of these studies, equations were developedto predict CO2 evolution of stored corn as a function of moisture content, temperature, and mechanical damage level. Laterresearch has added information on genetic hybrid resistance to fungal growth and fungicide effects. This article assemblesthe original equations derived from 1960s studies, plus relevant results from later research, into a comprehensive set ofequations to predict CO2 evolution and dry matter loss for corn stored at 15 to 35% moisture content (wet basis) andtemperatures from 0 to 49C. Effects of mechanical damage, genetic resistance to fungi, and fungicides are considered. Atable of predicted shelled corn storage times for 0.5% dry matter loss and a table of multipliers for other dry matter loss levelsare presented.

Note. Effect of Nixtamal Degermination on Some Physical Properties of Corn Masa and on Sensory Characteristics of Corn Tortillas

Laboratory-made, whole and degermed corn masa flours (DCM) at 50 and 100% levels were prepared to determine the effects of germs on physical properties and sensory characteristics of masa and corn tortillas. DCM flours were finer in particle size than whole dry masa flour. Whiteness of dry masa flours, calculated as total color difference, increased with degerming. Removal of germs did not modify the dough adhesiveness or the rollability and typical flavor of corn tortillas. The 100% degermed tortillas were significantly more chewy and firm than the whole nixtamal tortilla based on sensory evaluation. Therefore, nixtamal degermination could not be considered as a process to reduce off-odors of stored corn masas.

THE FUMONISIN PARADOX: A REVIEW OF RESEARCH ON ORAL BIOAVAILABILITY OF FUMONISIN B1, A MYCOTOXIN PRODUCED BYFUSARIUM MONILIFORME

The fumonisins are a series of mycotoxins produced by Fusarium moniliforme, a ubiquitous contaminant of stored corn (maize) worldwide. Consumption of food products contaminated with F. moniliforme hasbeen correlated with increased risk of human esophageal cancer in epidemiological studies in southern Africa and China. The most abundant component, fumonisin B1 (FB1), was isolated from F. moniliforme culture extracts using a short-term tumor promoter bioassay to guide the fractionation. Purified FB1 has been confirmed to act as a tumor promoter in animal model systems; to cause hepatocellular carcinoma, cirrhosis and proximal tubule nephrosis in rats; and to mediate agriculturally significant diseases associated withconsumption of F. moniliforme-contaminated feeds, including equine leukoencephalomalacia and porcine pulmonary edema. However, studies on the toxicokinetics of radiolabeled and unlabeled FB1 carried out by three research groups in five animal species all indicate that it is absorbed very poorly ...

Tratamento inseticida e qualidade de sementes de milho durante o armazenamento

A presente pesquisa objetivou verificar os efeitos dos inseticidas deltametrina, clorpirifos, fosfina e da terra diatomácea no controle de insetos em sementes de milho, armazenadas durante 12 meses, visando oferecer alternativas de produtos inseticidas, utilizando delineamento inteiramente casualizado. As sementes do híbrido AG 303, tratadas com deltametrina e clorpirifos, aplicados na forma isolada ou em combinação, fosfina e terra diatomácea, foram acondicionadas em sacos de papel multifoliado e armazenadas por doze meses (maio/1997 a abril/1998) em condições normais de ambiente. Em intervalos bimestrais, sete épocas no total, as sementes foram submetidas às seguintes determinações: exame de sementes infestadas, massa de 100 sementes, teste de germinação, teste de frio, envelhecimento acelerado, condutividade elétrica, emergência de plântulas em campo e velocidade de emergência de plântulas. A análise dos dados e interpretação dos resultados permitiram concluir que: os inseticidas deltametrina e clorpirifos (isolados ou associados), a terra diatomácea e a fosfina promovem, de maneira similar, o controle de insetos-praga que ocorrem no armazenamento e não causam toxicidade às sementes; a qualidade fisiológica das sementes é efetivamente preservada pelos tratamentos com inseticidas químicos e terra diatomácea.

Efficacy of Malathion Against Coleopteran Populations in Newly-Harvested Versus Year-Old Stored Corn2

The impact of malathion treatment and duration of storage prior to treatment on species composition and relative abundance of beetle pests was investigated in shelled corn in newly-constructed galvanized steel bins. Corn was sampled monthly for insects with plastic probe traps from January through September 1989. Red and confused flour beetles, Tribolium spp., hairy fungus beetle, Typhaea stercorea (L.), flat and rusty grain and flour mill beetles, Cryptolestes spp., and foreign grain beetle, Ahasverus advena (Waltl), were most abundant in traps, but plaster beetle, Cartodere constricta (Gyllenhal), minute brown fungus beetle, Corticaria pubescens (Gyllenhal), antlike flower beetle, Anthicus spp., and larger black flour beetle, Cynaeus angustus (LeConte), also were trapped. Greater numbers of the four major beetle species were trapped in older corn and in corn that was not treated with malathion and, depending on species, trap catch peaked in August or September. Information gathered during this investigation adds to our knowledge of insect infestation and insecticide application to on-farm stored corn and confirmed earlier reports that T. stercorea and A. advena potentially are pests of stored shelled corn. Thorough inspection and sampling should be conducted throughout the storage period, but especially after grain temperatures warm above 20°C.

EFEITO DA TEMPERATURA NO PARASITISMO DE Trichogramma pretiosum Riley, 1879 SOBRE OVOS DE Sitotroga cerealella (Olivier, 1819)

Avaliou-se o efeito da temperatura no parasitismo de Trichogramma pretiosum Riley, 1879 sobre ovos de Sitotroga cerealella (Olivier, 1819), para sua utilização em criações massais e/ou para o controle biológico desta traça de grãos armazenados. Os parasitóides foram mantidos sob as temperaturas de 18, 20, 22, 25, 30 e 32°C, durante 48 horas, com umidade relativa de 60±10% e fotofase de 14 horas, em todas as condições. O parasitismo foi avaliado pela contagem do número de ovos pretos (característica do parasitismo) e pelo número de parasitóides emergidos. As altas temperaturas foram favoráveis ao desempenho de T. pretiosum que, a 30°C teve 97,6% das fêmeas parasitando, com uma média de 18,8 ovos parasitados em 48 horas e com uma viabilidade de 88,5%.

Implications of Spatial Distribution of Insect Populations in Storage Ecosystems

Integrated management of storage pests requires understanding storage ecosystems and accurately monitoring pest population levels. Geostatistical techniques for spatial analysis provide a powerful tool to assist in biological interpretation of sample counts and trip captures of insects, as well its interpretations of physical measurements such as grain temperature and moisture content. Contour analysis is 3-step process. Data are first posted to a map of sample points; then a denser grid of data points is generated by interpolation (using one of several algorithms) and contours (lines joining points with equal values) are drawn at some fixed interval. This provides a contour display, showing the value of the variable at all points on the surface represented by the sample points. The utility of this method in stored-product protection is illustrated by a series of studies based on data sets for stored corn. These include comparison of spatial distribution of species and species interactions; analysis of temporal changes in distribution, precision targeting, and evaluation of control measures; interpretation of trap cattch; examination of physical variables and interactions of insects with the physical environment; and analysis of goodness of fit of contour surfaces to the data. The utility of techniques such as grid subtraction and construction of probability contours is demonstrated.

Carbon Tetrachloride Retention by Modern and Buried Soil A Horizons

Carbon tetrachloride (CCl4) was commonly used as a fumigant for stored corn (Zea mays L.) and other grains. This practice and other industrial uses have resulted in instances of soil and groundwater contamination. To better understand the potential for downward CCl4 movement, retention by a buried soil A horizon was compared with that of the modern A horizon in that same location and its loess C parent material. Batch equilibration was used to determine sorption coefficients (Kd) to compare retention among horizons. Mean Kd values were 0.83 (standard deviation [SD] = 0.18) for the modern A, 0.36 (SD = 0.10) for the loess C and 0.41 (SD = 0.07) for the buried A. Mean organic carbon (OC) contents were 14.9 g kg−1 (SD = 2.6) for the modern A, 1.3 g kg−1 (SD = 0.50) for the loess C, and 5.3 g kg−1 (SD = 0.60) for the buried A. Sorption coefficients were most strongly related to percent OC (R = 0.91 across all soils). Log OC coefficients (log Koc) were 1.74 (SD = 0.04) for the modern A, 2.43 (SD = 0.18) for the loess C, and 1.89 (SD = 0.10) for the buried A. The OC coefficient varied with OC content of the horizons. This variation may be attributed to qualitative chemical differences in the organic matter fractions. This may also be caused by the increased importance of the clay mineral fraction at low OC contents, leading to falsely high Koc values. The presence of a buried A horizon may help retard movement of CCl4 to groundwater.

An empirical test of the effect of basis risk on cash market positions

Traditional theory holds that hedgers use futures markets to reduce the amount of price risk they bear. In doing so, they trade price risk for basis risk, that is, unexpected movements in the difference between the spot and futures prices. Theoretical work has shown that the presence of basis risk reduces the position in the cash market as well as the relative use of futures as a hedging instrument. This paper empirically measures the effect of basis risk on the cash market position, using data on the storage of corn. Results show that basis risk statistically and economically significantly reduces the level of storage. The implications of basis risk on cash market positions extend beyond commodity storage to any hedging situation, including the use of currency futures to insure against exchange rate risk.

Host‐searching and mating in an outbreeding parasitoid wasp

Abstract. Female parasitoid wasps (Hymenoptera) must search for hosts to reproduce, but only require mates if their broods are to contain female progeny. In outbreeding species, females locate mates after dispersal from the emergence site. Unmated females may therefore face a trade‐off between searching for hosts and searching for mates, if hosts and mates are spatially separated. In the outbreeding parasitoid Bracon hebetor Say (Hymenoptera: Braconidae), males and females are spatially segregated in the field. Females are found primarily below the surface of stored corn where they search for hosts, whereas males are found on or above the surface. Wasps placed in laboratory observation chambers designed to mimic B.hebetor's stored corn habitat distributed themselves in a manner consistent with field observations. Males remained on the surface of the grain, whereas females moved below the surface to attack hosts. In the laboratory, female distribution was influenced by their mating status, the presence of males or hosts, and female age. Virgin females were more reluctant to move into the corn than were mated females, younger females foraged deeper than older females, and all females moved deeper into the com when males were present. 10% of all females did not mate even when males were present in the chambers, a percentage consistent with previous observations from the field. If B.hebetor faces a trade‐off between host‐searching and mate‐searching, the trade‐off seems to be part of 'split sex ratio strategies', with some females remaining constrained to producing only male offspring.

Effects of Maize Weevils (Coleoptera: Curculionidae) on Production of Aflatoxin B1 by Aspergillus flavus in Stored Corn

Insects play an important role as facilitators of the aflatoxin-producing fungus, Aspergillus flavus Link, in both preharvest and postharvest corn. The current study investigated the role of maize weevils, Sitophilus zeamais Motschulsky, in enhancing aflatoxin B1 content in stored corn. In laboratory experiments, aflatoxin B1 was quantified with an indirect enzyme-linked immunosorbent assay (ELISA) on corn following artificial infestation with adult weevils that had each been topically treated with 100 spores of A. flavus. Corn kernels infested with A. flavus-contaminated weevils had significantly higher levels of aflatoxin B1 than A. flavus-inoculated corn without weevils. The presence of maize weevils resulted in increased kernel moisture content during incubation, and grain moisture was positively correlated with aflatoxin content across treatments receiving spores. Aflatoxin B1 levels were higher in corn treated with fungus-contaminated weevils compared with corn that was mechanically damaged and inoculated with spores, which in turn had more aflatoxin than undamaged corn treated with spores. Aflatoxin B1 content in corn increased with time of weevil exposure from 7 to 21 d, but decreased after 28 d of exposure. Aflatoxin levels in infested corn increased significantly with increased numbers of A. flavus-contaminated weevils. Maize weevils carried spores both internally and externally; however, substantial numbers of spores were intimately associated with the exoskeleton of adult weevils. These findings indicate that maize weevils facilitate the growth of A. flavus and aflatoxin production in corn by increasing surface area susceptible to fungal infection and increasing moisture content as a result of weevil metabolic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Seasonal abundance and spatial patterns of the predator Lyctocoris campestris in stored corn*

AbstractA two‐year sampling study (1992–93) in a flat storage of shelled corn showed that the larger pirate bug, Lyctocoris campestris (F.) (Heteroptera: Anthocoridae), can be detected by relative sampling techniques as early as the second week of May. The perceived seasonal pattern of L. campestris varied with trapping method. Of the three relative sampling methods used, probe traps consistently captured more bugs of both sexes than cardboard traps in the grain and sticky flight traps. Probe traps showed a third degree polynomial trend through the season. On the other hand, flight traps were effective for monitoring L. campestris population during early and mid‐summer when temperatures were high, but the effectiveness declined during late summer and early fall. Cardboard traps showed the opposite trend to those of flight traps, with increasing L. campestris abundance during the fall when bugs sought refuge as temperature decreased. Sampling date and environmental factors, including grain moisture content, air and grain temperatures were correlated with trap capture. Earlier work reported that L. campestris showed a highly female biased sex ratio in the field as opposed to a 1:1 sex ratio in laboratory colonies. The present study found that the estimate of sex ratios in the field can differ with trapping methods. Of the three relative sampling methods used, flight and cardboard traps, in most cases, showed no deviation from a 1:1 sex ratio. Probe traps, however, indicated a highly female biased sex ratio in field populations. Absolute sampling using a 1140 ml cup sampler also showed no deviation from a 1:1 sex ratio in the field population. The data suggested that relative sampling methods may be inappropriate for sex ratio estimation in the field. Thus, an absolute sampling method is required for determination of the true field sex ratio of L. campestris. Analyses of dispersion patterns showed that both males and females of L. campestris exhibit an aggregated spatial distribution in the grain.

Fungal species composition and abundance on stored corn as influenced by several management practices and maize weevil (Coleoptera: Curculionidae)

The purpose of this study was to examine the effect of several management tactics and Sitophilus zeamais Motschulsky (maize weevil) on fungal species composition and abundance on stored corn (maize). The most abundant fungi isolated from Pioneer hybrids 3378 and 3320 were Fusarium sp., Penicillium spp., Rhizopus sp., Aspergillus glaucus and A. flavus. High temperature (36 °C) inhibited the growth of Fusarium sp., Penicillium spp., Rhizopus sp. and A. flavus, while the growth of A. glaucus increased. Low initial kernel moisture content (9.7%) appeared to inhibit the growth of some fungi ( Fusarium sp. and A. glaucus) while the growth of others ( Penicillium spp. and A. flavus) increased. Surface disinfection with bleach reduced populations of Penicillium, Rhizopus, A. glaucus and A. flavus, while permitting an increase of Fusarium. Biotic factors also exert considerable control over fungal populations. Hybrid selection affected all major species except Fusarium. The mere introduction of maize weevils, even when killed within 24 h by malathion, increased the abundance of Penicillium spp. and A. glaucus.

Simulation to Evaluate Dairy Manure Systems

An existing dairy forage system model (DAFOSYM) was expanded to include submodels for manure production, collection, storage, and application to crop land. The original DAFOSYM simulated the growth, harvest, storage, and utilization of alfalfa and corn on a dairy farm over 25 years of weather. The revision allowed simulation of the quantity and nutrient content of manure produced as a function of feed composition and consumption, milk production, and animal growth. Nutrient losses in manure handling, storage, and application were subtracted to determine nutrients available for crop growth. The facilities, machinery, labor, and fuel required were modeled to determine the costs of manure handling. The integrated model provided a tool for evaluating and comparing the long-term performance and economics of alternative manure systems for dairy farms and their interaction with feed production. Manure systems using long-term storage with spreading, injection, or irrigation have greater direct costs to the farmer than the daily haul system commonly used in the upper midwest. If long-term storage systems are required to protect the environment, the annual net cost of manure handling will increase up to $65/cow for small (60 cow) and $45/cow for large (250 cow) dairy farms.