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PubMed2004

Analysis of heat-processed corn foods for fumonisins and bound fumonisins.

Thirty retail samples of heat-processed corn foods, i.e. corn flakes, corn-based breakfast cereals, tortilla chips and corn chips, were analysed for fumonisins--fumonisin B1 (FB1), fumonisin B2 (FB2) and hydrolysed FB1 (HFB1)--as well as for protein- and total-bound FB1. Bound (hidden) fumonisins cannot be detected by conventional analysis. Improved methods for the determination of bound FB1 were developed. The protein-bound FB1 was extracted with 1% sodium dodecylsulfate (SDS) solution. The SDS, which interfered with high-performance liquid chromatography (HPLC) analysis, was then separated from protein-bound FB1 by complexing with methylene blue followed by solvent extraction and hydrolysis with 2 N KOH. To measure total-bound FB1, the sample itself was hydrolysed with KOH. In both cases, clean-up was accomplished on an OASIS polymeric solid-phase extraction column and the bound fumonisins were determined by HPLC measurement of HFB1. Fourteen of 15 samples of corn flakes and other corn-based breakfast cereals analysed contained detectable levels of FB1 with a mean in positive samples of 67ng g(-1) (13-237 ng g(-1)). Two samples also had detectable levels of FB2 (21-23ng g(-1)). Bound FB1 was found in all samples; the mean protein-bound FB1 measured was 58 ng g(-1) (22-176 ng g(-1)) and the mean total-bound FB1 measured was 106 ng g(-1) (28-418 ng g(-1)), reported as FB1 equivalents after correction for recoveries of HFB1. There was an average of about 1.3 times more FB1 in the bound form compared with extractable FB1, and this was about twice as much as protein-bound FB1. Seven of the 15 samples of alkali-processed corn-based foods, such as tortilla chips and corn chips, contained FB1 and three contained HFB1 with means in measurable positive samples of 78 (48-134) and 29 (13-47) ng g(-1), respectively. Five of these alkali-processed corn foods contained bound FB1; the mean measurable protein-bound FB1 was 42 ng g(-1) (39-46 ng g(-1)) and the mean measurable total-bound FB1 was 100 ng g(-1) (54-209 ng g(-1)). HFB1 derived from bound FB1 in selected samples was confirmed by HPLC with mass spectrometry (MS).

Carcinogens, Environmental↗
PubMed2004

Fumonisins in Brazilian corn-based foods for infant consumption.

A survey of 196 samples of corn-based infant foods from 13 cities of Sao Paulo State, Brazil, was carried out to investigate the fumonisin contamination in the products. Based on their ingredients, the products were divided into seven groups: infant cereal designated as types A-D, corn meal, corn starch and instant cereal baby food. Although certain infant food samples were free of fumonisin contamination (<20 microg kg(-1); corn starch and infant cereals of type A, B and D), contamination levels in the other products (corn meal, instant corn-based baby food and cereal type C) were of concern, particularly those in corn meal. All samples in these categories contained fumonisins. The mean level for total fumonisins (FB1 + FB2 + FB3) in corn meal was 2242 microg kg(-1) (maximum 8039 microg kg(-1)), in instant corn-based baby food was 437 (maximum 1096) microg kg(-1) and in infant cereal type C was 664 (maximum 1753) microg kg(-1).

Brazil↗
PubMed1997

Anti-aflatoxin mutagenic factors in corn.

Extracts, isolated through sequential fractionation and partition procedures described previously (Martinez et al. 1994) from aflatoxin-free corn and aflatoxin-contaminated corn with and without ammonia treatment, were investigated for mutagenic potential using the Ames test (TA 100 tester strain). 2-Aminofluorene (2-AF) and pure aflatoxin B1 (AFB1) were used as positive controls. Although TA100 showed mutagenic response to pure AFB1 at a dose of ca 10 ng/plate, all isolates tested from ammonia-treated aflatoxin-contaminated corn containing 7500 ng AFB1/g did not exhibit positive results in the Ames test. Additionally, isolates from non-ammonia-treated aflatoxin-contaminated corn failed to give positive mutagenic potentials. These results indicate that differences between the mutagenic potentials of pure aflatoxins and of aflatoxins in naturally-contaminated corn exist. CH2Cl2 extracts (the fractions containing aflatoxins) obtained from aflatoxin-contaminated corn with and without ammonia treatment were applied to preparative thin layer chromatography (TLC) in an effort to separate aflatoxins and/or ammonia/aflatoxin reaction products from the "unknown interfering materials' existing in the corn matrix. Each of the fractions separated by TLC was tested by the Ames test with S9 activation and none of them gave a mutagenic response to TA100. CH2Cl2 extracts in dimethylsulphoxide (DMSO) obtained from non-ammonia-treated aflatoxin-free corn were spiked with pure AFB1 and tested by TA100 with S9 activation. Again, no positive responses were observed. These findings provide further evidence of "unknown interfering materials' in corn which may bind with aflatoxin and/or can be extracted by CH2Cl2 together with aflatoxin, and, therefore, block the mutagenic activity of aflatoxin in the Ames test. Those materials were not separated from the aflatoxins by the TLC technique used in the present study. Possible reasons and further studies required to evaluate this phenomenon are discussed.

Aflatoxins↗
PubMed2002

Enhancement of vitamin E levels in corn.

Vitamin E is the common name that describes eight naturally occurring compounds possessing alpha-tocopherol activity. These eight vitamin E compounds are collectively termed tocols, and all have antioxidant activity. There is natural variation among different corn breeding lines for levels of tocols. The two predominant isomers present in corn grain are gamma-tocopherol and alpha-tocopherol. Alpha-tocopherol is considered more desirable for human and animal consumption because it has higher biological activity than gamma-tocopherol. Most corn breeding lines naturally have much more gamma-tocopherol than alpha-tocopherol. Therefore a breeding goal is to increase levels of alpha-tocopherol relative to gamma-tocopherol. However, recent research suggests that gamma-tocopherol and compounds metabolized from it have properties important to human health that are unique from properties of alpha-tocopherol. Therefore it may be desirable to not only increase levels of alpha-tocopherol in corn grain, but also levels of gamma-tocopherol. Determination of levels of tocopherols in corn grain is very laborious, requires HPLC analysis and is too time consuming for use in routine commercial corn breeding programs. Therefore we are performing biotechnology enabled molecular marker mapping of chromosomal regions with genes that control levels and ratios of alpha- and gamma-tocopherol. Breeders can use molecular markers we have identified to expediently select for desirable alleles of genes that will improve levels of alpha- and gamma-tocopherol in corn grain, without having to perform laborious HPLC assays. Another biotechnology strategy we have initiated is genetic transformation of corn with the gamma-tocopherol methyl transferase gene to enhance conversion of gamma-tocopherol to alpha-tocopherol and thus increase levels of alpha-tocopherol. This transgenic strategy has been demonstrated in the model plant Arabidopsis, and we are now applying this approach to corn.

Biotechnology↗
PubMed2005

Ensiling characteristics, nutrient composition, and in situ ruminal and whole tract degradability of brown midrib and leafy corn silage.

A study was conducted to compare the ensiling characteristics, chemical composition, and the ruminal and total tract nutrient degradabilities of leafy (Cargill F227) and brown midrib (Mycogen TMF94) corn silage hybrids. Corn was grown in Saint-Jean-sur-Richelieu, Quebec, Canada, harvested at a target 350 g kg(-1) dry matter (DM) content, and ensiled in mini-silos for 0, 2, 4, 8, 16, and 45 d. Two non-lactating Holstein cows fitted with ruminal and proximal duodenal cannulae were used to determine ruminal and whole tract nutrient degradability. Forage from both hybrids went through a rapid fermentation with a sharp decline in pH during the first 2 d of ensiling, pH in both silage being less than 4.0 after 45 d. Lactic acid concentration was however greater for leafy than brown midrib corn. Chemical analysis of silage after 45 d of ensiling revealed that hybrids differed in their composition. Compared to leafy corn, brown midrib corn had lower neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), crude protein (CP), and neutral detergent and acid detergent insoluble proteins, but higher starch and net energy of lactation (NEL) values. Results of the in situ incubation experiment indicated that compared to leafy corn brown midrib corn had greater ruminal DM (64 vs. 54%), CP (73 vs. 71%), and NDF (32 vs. 24%) degradabilities. Brown midrib corn silage also had greater DM ruminal (53 vs. 48%) and total tract (67 vs. 61%) digestibilities, as well as greater NDF ruminal (34 vs. 25%), intestinal (10 vs. 8%), and total tract (43 vs. 33%) digestibilities. Type of corn hybrid will thus greatly affect silage chemical composition and nutrient digestibility.

Animal Nutritional Physiological Phenomena↗
PubMed2000

Waxy corn starch: a potent cofiller in pellets produced by extrusion-spheronization.

The purpose of this study was to assess the usefulness of waxy corn (maize) starch as a cofiller and diluent in pellets produced by aqueous extrusion-spheronization. Waxy corn starch was combined with microcrystalline cellulose (MCC) in the range of 20-50% of the entire composition. Pellets containing ordinary corn starch or lactose with MCC were used as reference. The shape of pellets was characterized using an optical microscopic image analysis system. The surface and cross-sectional structure were investigated by means of scanning electron microscopy (SEM). The replacement of ordinary corn starch by waxy corn starch made it possible to increase the amount of starch from 20 to 40%. The pellets containing 50% waxy corn starch were of poorer quality but superior to those containing 30% corn starch. The surface structure became slightly more irregular with respect to the amount of either starch, and a cavity was formed inside the pellet during the spheronization. The origin of starch did not affect the surface structure of the pellets. Waxy corn starch is a potential cofiller: the amount of MCC can be reduced in pellets produced by extrusion-spheronization by using waxy corn starch as a cofiller. This enables the reduction of the manufacturing cost of pellets with low drug load.

Cellulose↗
PubMed2003

Economics versus alleles: balancing integrated pest management and insect resistance management for rotation-resistant western corn rootworm (Coleoptera: Chrysomelidae).

Western corn rootworm, Diabrotica virgifera virgifera LeConte, has overcome crop rotation in several areas of the central United States. We expanded a simple model of adult behavior and population genetics to explain how rotation resistance may have developed and to study ways to manage the western corn rootworm in a landscape of corn, soybean, and winter wheat where evolution of resistance may occur. We modeled six alternative management strategies over a 15-yr time horizon, as well as a strategy involving a 2-yr rotation of corn and soybean in 85% of the landscape, to investigate their effectiveness from both a biological and economic perspective. Generally, resistance to crop rotation evolves in fewer than 15 yr, and the rate of evolution increases as the level of rotated landscape (selection pressure) increases. When resistance is recessive, all six alternative strategies were effective at preventing evolution of rotation resistance. The two most successful strategies were the use of transgenic rotated corn in a 2-yr rotation and a 3-yr rotation of corn, soybean, and wheat with unattractive wheat (for oviposition) preceding corn. Results were most sensitive to increases in the initial allele frequency and modifications of the density-dependent survival function. Economically, three alternative strategies were robust solutions to the problem, if technology fees were not too high. Repellant soybean, attractive rotated corn, and transgenic rotated corn, all in 2-yr rotations, were economically valuable approaches. However, even the currently common 2-yr rotation was economical when resistance was recessive and the actual costs of resistance would not be paid until far in the future.

Agriculture↗
PubMed2004

Ovarian development and ovipositional preference of the western corn rootworm (Coleoptera: Chrysomelidae) variant in east central Illinois.

The rotation of maize, Zea mays L., and soybean, Glycine max (L.) Merr., has been the traditional cultural tactic to manage the western corn rootworm, Diabrotica virgifera virgifera LeConte, in the Corn Belt. The reduced effectiveness of this rotation as a pest management tool in east central Illinois, northern Indiana, and southern Michigan can be explained by the shift in the ovipositional behavior of the new variant of western corn rootworm. The objective of this study was to evaluate the influence of maize, soybean, oat, Avena sativa L., stubble, and alfalfa, Medicago sativa L., on the ovarian development and ovipositional preferences of the variant western corn rootworm. Field research was conducted near Urbana, IL, during 1998-2000. Gravid females were present throughout the season in all crops, and due to the prolonged period in which western corn rootworm females can lay eggs, none of the crops were immune from oviposition. Results indicated that the western corn rootworm variant oviposits in maize, soybean, oat stubble, and alfalfa In 1998 and 1999, maize was the preferred oviposition site among crops; however, in 2000, maize, soybean, and oat stubble treatments had similar densities of western corn rootworm eggs. Lack of oviposition preference of the western corn rootworm variant demonstrated in this experiment represents a reasonable explanation of why the effectiveness of the rotation strategy to control western corn rootworm has diminished.

Animals↗
PubMed2003

Iron bioavailability and utilization in rats are lower from lime-treated corn flour than from wheat flour when they are fortified with different sources of iron.

Although iron bioavailability from wheat flour fortified with iron has been widely studied, the bioavailability of lime-treated corn flour has not been evaluated sufficiently. We compared iron bioavailability and utilization of lime-treated corn flour and wheat flour supplemented with various iron sources. Bioavailability and utilization were determined in Sprague-Dawley rats using the iron balance and hemoglobin depletion-repletion methods. Rats were iron depleted by feeding them a low iron, casein diet for 10 d. During the repletion period, the rats were fed diets based on lime-treated corn flour or wheat flour, both supplemented with ferrous fumarate, ferrous sulfate, ferric citrate and reduced iron for 14 d. Hemoglobin was determined at the end of depletion and repletion periods. The phytate concentration was lower in wheat flour (114 mg/100g) than in lime-treated corn flour (501 mg/100g). Iron bioavailability and utilization by rats were higher from fortified and unfortified wheat flour than from the lime-treated corn flour counterparts. Iron utilization was greater in rats fed wheat flour supplemented with ferrous sulfate, followed by fumarate and citrate than in rats fed reduced iron. In lime-treated corn flour, iron utilization by rats fed unfortified flour and flour fortified with reduced iron did not differ, but utilization was higher in rats fed corn flour fortified with iron sulfate, fumarate and citrate than with reduced iron. We conclude that fortification of lime-treated corn flour with reduced iron has no effect on iron bioavailability or utilization, probably due to the high phytate content. Other iron compounds must be selected to fortify lime-treated corn flour when intended for public nutrition programs.

Animals↗
PubMed2003

Comparison of broiler performance when fed diets containing grain from roundup ready (NK603), yieldgard x roundup ready (MON810 x NK603), non-transgenic control, or commercial corn.

Two 42-d experiments compared the nutritional value of the glyphosate-tolerant corn event NK603 (Roundup Ready corn) (experiment 1) and the combined traits, insect-protected corn event MON 810 (YieldGard com) x glyphosate-tolerant corn event NK603 (experiment 2) to their respective non-transgenic controls and to commercial reference corn, when fed to growing broilers. For each experiment, a randomized complete block design was used with eight dietary treatments in each of five replicated blocks of pens (eight pens for males and eight pens for females per block). Final live weights and feed conversion were not different (P > 0.05) across all treatments in both experiments. In experiment 1, broilers fed diets containing Roundup Ready corn had similar feed conversion adjusted for mortalities to those fed the non-transgenic control and one of the commercial corn diets. Chill weights and thigh, drum, and wing weights were not affected by diets. Differences (P < 0.05) were noted for breast meat and fat pad weights across treatments. In experiment 2, the adjusted feed conversion and carcass parameters were not affected by diets. Differences (P < 0.05) were noted only for protein content of breast meat. Differences observed in both experiments were consistent with natural variability. Broilers in general performed consistently and had similar carcass yields and meat compositions when fed diets containing Roundup Ready corn or YieldGard x Roundup Ready corn as compared with their respective non-transgenic control and commercial diets supporting similar feeding values among diets.

Adipose Tissue↗
PubMed2005

Evaluation of transgenic hybrid corn (VIP3A) in broiler chickens.

A 49-d feeding study evaluated whether standard broiler diets prepared with Syngenta Seeds VIP3A transgenic derived corn grain had any unanticipated adverse effects on male or female broiler chickens as compared with diets prepared with nontransgenic (isoline) control corn grain. Two commercial lots of grain grown in North Carolina during the 1999 (NC 1999) and 2000 (NC 2000) seasons were included for reference purposes. Broiler growth was excellent with males reaching 3466 g and females reaching 2882 g at 49 d of age. Final BW of the VIP3A, isoline, and NC 1999 corn groups were within 21.1 g, whereas the NC 2000 group was 42.4 g lower than the lowest of this group. There was no overall corn source effect on adjusted feed conversion ratio (FCR) or mortality to 49 d of age. Carcass analysis demonstrated no differences in percentage yield due to corn source among males and females other than percentage wings in females. Comprehensive clinical chemical analyses of blood taken from representative birds at 49 d of age showed no differences due to corn sources. The transgenic VIP3A hybrid diets numerically supported the most rapid broiler chicken growth, the second lowest mortality rate and best FCR, without practical differences in carcass yield. The few differences found in this study were not unique to a given corn source but instead appeared to be distributed equally across the diet groups evaluated in the study. Although it was not clear whether small differences in performance were attributable to the transgenic corn per se or were due to possible slight differences in overall composition of the formulated diets, it was clear that the transgenic corn had no deleterious effects on broiler performance and carcass yield in this study.

Animal Feed↗
PubMed2005

Effect of Bt corn on broiler growth performance and fate of feed-derived DNA in the digestive tract.

The aim of the study was to evaluate the effect on broiler performance of transgenic Bacillus thuringiensis (Bt) corn containing the Cry1A(b) protein compared with the corresponding near isogenic corn and to analyze the degradation of the Cry1A(b) gene in the digestive tract. Ross male broilers (432) were fed for 42 consecutive days with diets containing Bt or isogenic corn. Diet, Bt corn, and the isogenic form of the Bt corn were analyzed for composition and aflatoxin B1, fumonisin B1, and deoxynivalenol contents. Broiler body weight and feed intake were recorded at regular intervals (d 0, 21, and 42). The presence of the Cry1A(b) gene and plant-specific genes Zein and Sh-2 in gut contents of crop, gizzard, jejunum, cecum, and samples of blood was determined in 10 animals per treatment at the end of the trial using a PCR technique. Chemical composition was not different between Bt and its isogenic form, whereas the fumonisin B1 content for Bt was lower than for isogenic corn (2,039 vs. 1,1034 ppb; P < 0.05). The results of the growth study showed no difference for average daily weight gain (129.4 vs. 126.0 g/d), feed intake (63.4 vs. 61.8 g/d), and feed conversion ratio (1.95 vs. 2.02) among the groups. No significant relationship was observed between mycotoxins content and growth performances. Feed-derived DNA is progressively degraded along the digestive tract. Detection frequency of short fragments of maize-specific high copy number Zein gene was high but significantly decreased in distal sectors. An 1,800-bp fragment of the Cry1A(b) gene, corresponding to the minimal functional unit, was detected only in crop and gizzard of birds fed Bt corn. Sh-2 showed the same detection frequency of Cry1A(b) and was also found in birds fed isogenic corn. Blood samples were positive with low frequency only for the Zein gene fragment. No significant difference in DNA detection was observed between birds fed Bt and isogenic corn, indicating that DNA derived from transgenic feed undergoes the same fate as isogenic feed.

Aflatoxin B1↗
PubMed1976

Acetylene reduction (nitrogen fixation) associated with corn inoculated with Spirillum.

Sorghum and corn breeding lines were grown in soil in field and greenhouse experiments with and without an inoculum of N2-fixing in Spirillum strains from Brazil. Estimated rates of N2 fixation associated with field-grown corn and sorghum plants were less than 4 g of N2/ha per day. The mean estimated N2-fixation rates determined on segments of roots from corn inoculated with Spirillum and grown in the greenhouse at 24 to 27 degrees C were 15 g of N2/ha per day (16 inbreds), 25 g of N2/ha per day (six hybrids), and 165 g of N2/ha per day for one hybird which was heavily inoculated. The corresponding mean rates determined from measurements of in situ cultures of the same series of corn plants (i.e., 16 inbreds, six hybrids, and one heavily inoculated hybrid) were 0.4, 2.3, and 1.1 g of N2/ha per day, respectively. Lower rates of C2H2 reduction were associated with control corn cultures which had been treated with autoclaved Spirillum than with cultures inoculated with live Spirillum. No C2H2 reduction was detected in plant cultures treated with ammonium nitrate. Numbers of nitrogen-fixing bacteria on excised roots of corn plants increased an average of about 30-fold during an overnight preincubation period, and as a result acetylene reduction assays of root samples after preincubation failed to serve as a valid basis for estimating N2 fixation by corn in pot cultures. Plants grown without added nitrogen either with or without inoculum exhibited severe symptoms of nitrogen deficiency and in most cases produced significantly less dry weight than those supplied with fixed nitrogen. Although substantial rates of C2H2 reduction by excised corn roots were observed after preincubation under limited oxygen, the yield and nitrogen content of inoculated plants and the C2H2-reduction rates by inoculated pot cultures of corn, in situ, provided no evidence of appreciable N2 fixation.

Acetylene↗
PubMed2005

Effects of selection for the timing of vegetative phase transition on corn borer (Lepidoptera: Noctuidae and Crambidae) damage.

In maize, Zea mays L., the timing of vegetative phase transition from juvenile to adult vegetative phases can be modified through selection. A reduction in the juvenile vegetative phase has been associated with resistance to diseases and pests. The major maize pest in temperate areas is Ostrinia nubilalis (Hübner) and in Europe Sesamia nonagrioides Lefebvre. The objective of our study was to determine the effects of divergent selection for the timing of vegetative phase transition in maize on resistance to corn borers. Three cycles of divergent selection for early and late phase transition in a field corn synthetic and in a sweet corn population were evaluated separately under S. nonagrioides and O. nubilalis artificial infestation. For the field corn experiment, yield and moisture improved with selection for phase transition in both directions, but improvement was due to artifacts of selection, rather than to the change in phase transition. There were no correlated responses for corn borer damage, yield, or grain moisture due to selection for the timing of vegetative phase transition. In the sweet corn experiment, selection for the timing of vegetative phase transition had no significant effects on corn borer damage in sweet corn harvested at the fresh stage. Our results do not support the use of phase transition as an indirect criterion for improving resistance to corn borers in maize. The relationship between phase transition and pest resistance reported by other studies could depend on the genotypes or could be too weak to be detected in a selection program with wild-type maize.

Animals↗
PubMedDate not supplied

Bioavailability of biosolids molybdenum to corn.

This study was part of a larger effort to generate field data appropriate to the assessment of biosolids molybdenum (Mo) risk to ruminants. Corn (Zea mays L.) is an important component of cattle diet, and is a logical crop for biosolids amendment owing to its high N requirement. Paired soil and corn stover samples archived from two unique field experiments were analyzed to quantify the relationship (uptake coefficient, UC) between stover Mo and soil Mo load. Both studies used biosolids with total Mo concentrations typical of modern materials. Data from long-term (continuous corn) plots in Fulton County, IL confirm expected low Mo accumulation by corn stover, even at very high biosolids loads and soil Mo loads estimated to be near 18 kg Mo ha(-1). Uptake slopes were actually negative, but USEPA protocol would assign UC values of 0.001. Data from plots in Minnesota also suggested essentially no correlations between stover Mo and soil Mo loads for continuous corn. However, greater Mo accumulation in corn grown following soybean [Glycine max (L.) Merr.] suggests the possibility of enhanced Mo bioavailability to corn in corn-soybean rotations. Nevertheless, molybdenosis risk to cattle consuming corn stover produced on biosolids-amended land is small as stover Mo concentrations were always low and stover Cu to Mo ratios exceeded 2:1, which avoids molybdenosis problems.

Agriculture↗
PubMed1990

Effects of buffer or DL-methionine with different amounts of supplemental corn on feed intake and nutrient digestion by Holstein steers consuming bermudagrass hay.

Two latin squares were conducted to determine the effects on feed intake and nutrient digestion of adding a ruminal buffer or DL-methionine to supplemental ground corn for Holstein steers (avg BW of 286 and 222 kg in Exp. 1 and 2, respectively) with ad libitum access to bermudagrass hay. In Exp. 1, steers were not supplemented (control) or were given .5 (LC) or 1.0% BW/d (HC) of ground corn without or with .021% BW of sodium bicarbonate (B). Total DMI was 2.39, 2.71, 2.79, 2.81 and 2.98% BW (effects of supplementation [P less than .05], level of corn [P less than .05] and buffer [P less than .06]), and OM digested was 3.56, 4.65, 4.65, 4.96 and 5.34 kg/d for control, LC, LCB, HC and HCB, respectively (effects of supplementation and corn level, P less than .05). In Exp. 2, corn levels were .24 and .74% BW/d and .0022% BW of DL-methionine (M) replaced B. Total DMI was 2.85, 3.00, 2.99, 3.22 and 3.34% BW (effects of supplementation and corn level, P less than .05), and digestible OM intake was 3.78, 4.24, 4.30, 4.84 and 5.12 kg/d for control, LC, LCM, HC and HCM, respectively (effects of supplementation and corn level, P less than .05). Overall, changes in feed intake and digestion with additions of a ruminal buffer and DL-methionine to corn supplements were not marked; however, buffer addition increased DMI intake to the greatest degree with 1.0% BW/d of corn.

Animal Feed↗
PubMed1991

Supplemental corn grain for steers grazing native rangeland during summer.

Effects of supplemental corn grain on forage OM intake (FOMI), digesta kinetics, ruminal fermentation patterns, in vitro OM digestibility (IVOMD), and in situ OM digestion were examined in steers grazing summer blue grama rangeland in northeastern New Mexico during July and August 1988. Sixteen ruminally cannulated steers (average BW 507 kg) were allotted to four treatments and individually fed whole-shelled corn at 0, .2, .4, and .6% of BW in a complete random design with repeated measurements over time. Forage OMI decreased linearly (P = .02) with increasing levels of supplemental corn; however, a tendency toward greater FOMI, as well as faster particulate and fluid passage, was observed when corn was fed at .2% of BW compared with 0, .4, or .6% of BW. Molar proportions of butyrate increased (P less than .10) but molar proportions of acetate and propionate, ruminal pH, and total VFA concentration did not change (P greater than .10) with added corn. Added corn linearly decreased (P less than .10) ruminal ammonia N concentrations in July, but patterns were inconsistent in August. A cubic response (P less than .05) for in situ OM disappearance with added corn was noted after 24, 72, and 96 h of incubation. Supplemental whole corn fed at .2% of BW had no detrimental effects and tended to increase FOMI. However, supplemental corn fed at .4 or .6% of BW decreased FOMI compared with 0 or .2% of BW.

Ammonia↗
PubMed1991

Relationships of body weight, forage composition, and corn supplementation to feed intake and digestion by Holstein steer calves consuming bermudagrass hay ad libitum.

Holstein steer calves (101 to 350 kg BW) consumed bermudagrass hay ad libitum without or with supplemental ground corn up to 1.0% of BW. As BW increased, total DMI increased quadratically (-2.459 + .05448 [BW]-.000073 [BW2] + .540 [corn DMI]; R2 = .83, sy.x = .655). Each kilogram of corn DM decreased bermudagrass DMI by .46 kg. Total digestible OM intake (kg) increased with BW and corn supplementation (.314 + .0127 [BW] + .441 [corn OM intake]; R2 = .79, sy.x = .444). Feed intake level accounted for approximately 2.5 times more variability in total digestible OM intake than digestion did. Corn supplementation decreased digestion of bermudagrass NDF (62.50 - 8.468 [corn DMI, % BW]; R2 = .13, sy.x = 8.121), with a similar decrease across BW. Increasing bermudagrass DMI (% of BW) decreased bermudagrass NDF digestion slightly, but variation accounted for was only 33% of that attributable to corn DMI (% of BW). Concentrations of common fiber fractions (NDF, ADF, cellulose, hemicellulose, and ADL) in bermudagrass explained very little variation in feed intake and digestion, indicating considerable influence of other factors. Bermudagrass intake and digestion were not related, and no substantial interactions were observed among steer BW, corn level, and bermudagrass composition.

Animal Feed↗