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PubMed2005

Comparison of broiler performance when fed diets containing corn grain with insect-protected (corn rootworm and European corn borer) and herbicide-tolerant (glyphosate) traits, control corn, or commercial reference corn--revisited.

A 42-d feeding experiment with growing Ross x Ross 508 broilers showed that the nutritional value of insect-protected and herbicide-tolerant corn was comparable to that of the genetically similar control and 5 commercial reference corn hybrids. MON 88017 provides protection from feeding damage by coleopteran pest corn rootworm and is tolerant to the action of glyphosate, the active ingredient in the Roundup family of agricultural herbicides. MON 88017 x MON 810 was developed by the traditional breeding of MON 88017 with MON 810, which provides protection from the European corn borer and other lepidopteran pests. A randomized complete block design was used with 8 dietary treatments in each of 5 replicated blocks of pens. No differences among diets were observed (P > 0.05) in performance (final live weights, feed intake, feed conversion, and adjusted feed conversion), carcass yield (chill, fat pad, breast, thigh, wing, and drum weight), or percentage of moisture, protein, and fat in breast meat and moisture and fat in thigh meat. Thigh protein was similar (P > 0.05) in broilers fed diets containing MON 88017 x MON 810 and conventional control or all commercial reference corns; however, differences (P < 0.05) were noted for the percentage of thigh protein among broilers fed the control and 2 of the 5 reference diets, attributable to biological variability among the conventional corn hybrids. Broilers overall performed consistently and had similar carcass yield and meat composition when fed diets containing MON 88017 or MON 88017 x MON 810 as compared with those fed the conventional control and commercial diets, supporting a conclusion of nutritional equivalence.

Animal Feed↗

PubMed2005

Comparison of broiler performance when fed diets containing corn grain with insect-protected (corn rootworm and European corn borer) and herbicide-tolerant (glyphosate) traits, control corn, or commercial reference corn.

Adipose Tissue↗

PubMed2005

Transgenic corn for control of the European corn borer and corn rootworms: a survey of Midwestern farmers' practices and perceptions.

In 2001, a self-administered questionnaire was sent to 1000 corn, Zea mays L., farmers in each of five states (Illinois, Indiana, Iowa, Minnesota, and Nebraska) to evaluate their perceptions of transgenic corn designed to control the European corn borer, Ostrinia nubilalis (Hübner), and corn rootworms, Diabrotica spp. Respondents returned 1,313 surveys (26.2%). Farmers with small acreages planted a greater portion of their corn (54.5%) with transgenic corn for control of European corn borer than farmers with large farms (39.2%). The majority (75.2%) of farmers use crop rotation to control the corn rootworm. Nine insecticides comprised 92.2% of the commercial soil insecticides used for control of corn rootworm larvae. More than one-third of the farmers in Illinois (33.5%) and Indiana (39.4%) treated first-year corn for corn rootworm, primarily due to western corn rootworm egg laying in soybean, Glycine max (L.). When asked whether they would plant transgenic corn protected against the corn rootworm, 35.0% of farmers responded they would, whereas 40.5% said they were unsure. The two greatest farmer concerns about transgenic corn were the ability to sell harvested grain (59.3%) and additional technology fees (54.8%). Respondents indicated that less farmer exposure to insecticide (69.9%) and less insecticide in the environment (68.5%) were the primary benefits of transgenic corn. Farmers who had no concerns about transgenic corn for rootworm control were more likely to purchase the product (46.8%). The most common refuge-planting options farmers favored were adjacent fields (30.9%) and split fields (29.9%). Farmers (21.1%) observed a yield increase (23.7 bu/ha [9.6 bu/acre]) when using transgenic corn for European corn borer control compared with non-transgenic corn. These data can help in understanding farmers' knowledge and concerns regarding transgenic corn. This information may be of value to guide researchers, extension specialists, and policy makers in designing insect resistance management and integrated pest management programs.

Agriculture↗

PubMed2002

Use of transgenic Bacillus thuringiensis Berliner corn hybrids to determine the direct economic impact of the European corn borer (Lepidoptera: Crambidae) on field corn in eastern Canada.

Transgenic corn expressing Bacillus thuringiensis Berliner (Bt corn) (Maximizer and Yieldgard hybrids, Novartis Seeds), non-Bt isolines and high-performance (check) hybrids were evaluated for European corn borer, Ostrinia nubilalis (Hübner), damage and grain yield in commercial strip plots across Ontario in 1996 and 1997. Bt corn hybrids reduced stalk tunneling damage by 88-100%. In 1996, minimal damage was found in locations where only one generation of European corn borer occurred per year. Bt corn proved its greatest potential for reducing the number and length of cavities below the primary ear in locations where two generations of European corn borer were present. A yield response to using Bt hybrids only occurred when levels of tunneling damage exceeded 6 cm in length. European corn borer infestations resulted in a 6 and 2.4% reduction in yield for 1996 and 1997, respectively, when Bt hybrids were compared with their non-Bt isolines. A linear relationship was found between tunnel length per plant in centimeters (x) and yield protection (%) obtained from using Bt corn (y) (y = 1.02 + 0.005x, r2 = 0.7217). At a premium of $34.58 Canadian (CDN) perhectare for Bt corn seed, an infestation of at least 6 cm of corn borer tunneling per plant was required to break even at a market price for corn of $2.50 per bushel CDN. During the period of study, low infestations (0-2 cm) of European corn borer occurred at 25% of the locations assessed, moderate infestations (4-6 cm) occurred at 42% of the locations, and high infestations (>6 cm) occurred at 33% of the locations. At a corn price of $3.00 per bushel CDN and seed premiums of $34.58 per hectare CDN, 5 cm of tunneling was required for a return on investment in Bt seed, comprising only 55% of the growers in the study. With infestations of more than 6 cm of tunneling occurring only 33% of the time, a return on seed investment would be realized in only one of three growing seasons. At a seed premium of $24.70 per hectare CDN per year, at least $74 per hectare CDN in the year of infestation would be required to make up for the two years of no return. In this study, a $74 per hectare CDN return at a corn price of $9.26 per hectare CDN with >16 cm of tunneling damage would have occurred only 7.3% of the time.

Animals↗

PubMed2004

Performance of growing-finishing pigs fed diets containing Roundup Ready corn (event nk603), a nontransgenic genetically similar corn, or conventional corn lines.

Two studies were conducted at two locations to evaluate growth performance and carcass characteristics of growing-finishing pigs fed diets containing either glyphosate-tolerant Roundup Ready (event nk603) corn, a nontransgenic genetically similar control corn (RX670), or two conventional sources of nontransgenic corn (RX740 and DK647). A randomized complete block design (three and four blocks in Studies 1 and 2, respectively) with a 2 x 4 factorial arrangement of treatments (two genders and four corn lines) was used. Study 1 used 72 barrows and 72 gilts (housed in single-gender groups of six; six pens per dietary treatment) with initial and final BW of approximately 22 and 116 kg, respectively. Study 2 used 80 barrows and 80 gilts (housed in single-gender groups of five; eight pens per dietary treatment) with initial and final BW of approximately 30 and 120 kg, respectively. Pigs were housed in a modified open-front building in Study 1 and in an environmentally controlled finishing building in Study 2. The test corns were included at a fixed proportion of the diet in both studies. Animals had ad libitum access to feed and water. Pigs were slaughtered using standard procedures and carcass measurements were taken. In Study 1, overall ADG, ADFI (as-fed basis), and gain:feed (G:F) were not affected (P > 0.05) by corn line. In Study 2, there was no effect of corn line on overall ADFI (as-fed basis) or G:F ratio. In addition, overall ADG of barrows fed the four corn lines did not differ (P > 0.05); however, overall ADG of gilts fed corn DK647 was greater (P < 0.05) than that of pigs fed the other corn lines. There was no effect (P > 0.05) of corn line on carcass yield or fatness measurements in either study. Differences between barrows and gilts for growth and carcass traits were generally similar for both studies and in line with previous research. Overall, these results indicate that Roundup Ready corn (nk603) gives equivalent animal performance to conventional corn for growing pigs.

Animal Feed↗

PubMed2004

Composition of grain and forage from corn rootworm-protected corn event MON 863 is equivalent to that of conventional corn (Zea mays l.).

Insect-protected corn hybrids containing event MON 863 protect corn plants against feeding damage from corn rootworm (Diabrotica), a major North American insect pest. Corn event MON 863 contains a gene that expresses an amino acid sequence variant of the wild-type Cry3Bb1 insecticidal protein from Bacillus thuringiensis. The purpose of this study was to compare the composition of corn containing event MON 863 with that of conventional nontransgenic corn. Compositional analyses were conducted to measure proximates, fiber, amino acids, fatty acids, minerals, folic acid, thiamin, riboflavin, vitamin E, antinutrients, and certain secondary metabolites in grain and proximates and fiber content in forage collected from a total of eight field sites in the U.S. and Argentina. Compositional analyses demonstrated that the grain and forage of event MON 863 are comparable in their nutritional content to the control corn hybrid and conventional corn. These comparisons, together with the history of the safe use of corn as a common component of animal feed and human food, support the conclusion that corn event MON 863 is compositionally equivalent to, and as safe and nutritious as, conventional corn hybrids grown commercially today.

Amino Acids↗

PubMed2005

Nutrient addition to corn masa flour: effect on corn flour stability, nutrient loss, and acceptability of fortified corn tortillas.

BACKGROUND: Iron, zinc, and vitamin B complex are among the most prevalent nutritional deficiencies in Mexico, with iron deficiency being the leading cause of anemia. Mexico has the highest per capita consumption of corn in the world, consumed mainly as tortilla. Thus, corn flour for making tortillas has been suggested as an effective strategy to overcome malnutrition in developing countries such as Mexico where corn is a staple food. The stability of micronutrients added to food is an important factor for the success of fortification programs. OBJECTIVE: The aim of this study was to evaluate the stability of corn flour fortified with micronutrients, and to measure the effect of micronutrient fortification on the sensory quality and stability of the fortificants in fresh and stored tortilla. METHODS: A commercially homogenized nonfortified corn flour (NCFC) produced from degermed white corn was fortified with a premix containing iron, zinc, thiamin, and riboflavin. Changes in thiamin, riboflavin, iron, and zinc content in fortified corn flour (FCF) and nonfortified corn flour (NFCF) during storage were investigated. Vitamin B1 and B2 content was determined by fluorescence spectroscopy while iron and zinc content was analyzed by atomic absorption. RESULTS: Thiamin content in FCF and NFCF showed a significant (p < .05) decrease (24% and 37%, respectively) after 90 days of storage. Riboflavin losses of 18% and 22% were observed for FCF and NFCF, respectively. FCF retained over 90% of iron, while zinc content remained constant. Losses of thiamin (27 to 39%) and riboflavin (37%) were produced during the process to convert corn masa flour into tortillas. CONCLUSIONS: Storage time slightly affected the stability of riboflavin and thiamin in FCF while the cooking process produced considerable losses of both vitamins. Tortillas made from FCF were well accepted by Mexican adults. We conclude that the addition of vitamins and minerals in the forms and quantities used in this study do not modify the shelf-life of corn flour, and neither do they cause sensorial changes in tortillas made from FCF.

Consumer Behavior↗

PubMed2005

Performance of growing-finishing pigs fed diets containing YieldGard Rootworm corn (MON 863), a nontransgenic genetically similar corn, or conventional corn hybrids.

Two studies were conducted at two locations to evaluate growth performance and carcass characteristics of growing-finishing pigs fed diets containing either YieldGard Rootworm corn (MON 863), a non-transgenic genetically similar corn (RX670), or two conventional nontransgenic corn hybrids (DK647 and RX740). A randomized complete block design with a 2 x 4 factorial arrangement of treatments (two genders and four corn hybrids) was used. Study 1 used 72 barrows and 72 gilts (progeny of Danbred sires x [Danbred x NE White line] dams grown from 22.7 to 117.0 kg BW). Pigs were housed in a modified open-front building in single-gender groups of six (six pens per dietary treatment). Study 2 used 80 barrows and 80 gilts (progeny of PIC 337 sires x C22 dams) grown from 29.5 to 114.9 kg BW. Pigs were housed in an environmentally controlled finishing building in single-gender groups of five (eight pens per dietary treatment). The test corns were included at a fixed proportion of the diet in both studies. Animals had ad libitum access to feed and water. Pigs were slaughtered at the end of the growth period using standard procedures, and carcass measurements were taken. There were no diet x gender interactions for growth performance or carcass measurements in either study. In both studies, overall ADG, ADFI, and G:F were not affected by corn hybrid. There was no effect of corn hybrid on carcass or LM quality measurements in Study 1. In Study 2, LM protein content was less (P< 0.05) for pigs fed RX740 compared with those fed either MON 863 or RX670; however, there was no effect of corn hybrid on other LM composition measures or on quality traits. In both studies, differences between barrows and gilts for growth and carcass traits were similar to previous research. These results suggest that the YieldGard Rootworm corn (MON 863) results in equivalent growth performance and carcass quality to nontransgenic corn hybrids in growing-finishing pigs.

Animal Feed↗

PubMed1987

Incidence of contamination with aflatoxin in precooked corn flour, corn grain and cracked corn.

A study was carried out to determine the presence and content of aflatoxins in 90 samples of precooked corn flour (23 yellow and 67 white), 40 samples of corn grain (30 yellow and 10 white), and 30 samples of yellow cracked corn. No aflatoxin was detected in white corn grain. The other investigated samples showed the following rates of contamination: yellow corn grain, 10%, ranging from less than 5 to greater than 10 ppb; yellow cracked corn, 16.6%, ranging from less than 5 to greater than 20 ppb; and white corn flour, 6%, and yellow corn flour, 87%. Of 14 aflatoxin positive samples tested, only 1 contained more than 20 ppb, the administrative guideline established by the US Food and Drug Administration (FDA). The results of this survey do not appear alarming because of the relatively low incidence and low levels of aflatoxin detected. However, since Venezuela is a big consumer of corn and corn-derived products, a more detailed investigation is suggested to establish the realistic levels of aflatoxin in these commodities.

Aflatoxins↗

PubMed2000

Glyphosate-tolerant corn: the composition and feeding value of grain from glyphosate-tolerant corn is equivalent to that of conventional corn (Zea mays L.).

Glyphosate-tolerant (Roundup Ready) corn line GA21 has been developed by genetic modification to tolerate glyphosate, the active ingredient in Roundup herbicide. The purpose of this study was to evaluate the compositional and nutritional safety of corn line GA21 compared to that of conventional corn. Compositional analyses were conducted to measure proximate, fiber, amino acid, fatty acid, and mineral contents of grain and proximate, fiber, and mineral contents of forage collected from 16 field sites over two growing seasons. The nutritional safety of corn line GA21 was evaluated in a poultry feeding study conducted with 2-day old, rapidly growing broiler chickens, at a dietary concentration of 50-60% w/w. Compositional analysis results showed that, except for a few minor differences that are unlikely to be of biological significance, the grain and forage of GA21 corn were comparable in their composition to that of the control corn line and to conventional corn. Results from the poultry feeding study showed that there were no differences in growth, feed efficiency, adjusted feed efficiency, and fat pad weights between chickens fed with GA21 grain or with parental control grain. These data taken together demonstrate that Roundup Ready corn is as safe and nutritious as conventional corn for food and feed use.

Amino Acids↗

PubMed1996

Fusaric acid and pathogenic interactions of corn and non-corn isolates of Fusarium moniliforme, a nonobligate pathogen of corn.

Fusarium moniliform is a nonobligate parasite of corn, which exists as a complex of closely related fungi from different mating population or biological species. Strains of this fungus isolated from corn, have been determined to belong to mating populations A, although other populations have been isolated from corn. The ultrastructural association of the fungus with corn during growth, and the effects of the host on suppression of disease suppression are reviewed. This fungus enters a relationship with corn cultivars that is not always pathogenic. Pathogenesis is delayed, if it ever occurs. F. moniliforme can exist entirely as an endophyte, systemically colonizing kernels, remaining there until germination upon which the fungus infects the emerging seedlings. The symptomless association persists during the growth cycle of corn, and the resulting endophytic hyphae may be the source of mycotoxin production. The host's ability to suppress the fungus appears to be related to one class of compounds, the cyclic hydroxamic acids and their decomposition products, which can be catabolized by the fungi of mating population A but not C.

Fusaric Acid↗

PubMed2004

Binomial sequential sampling plans for late instars of European corn borer (Lepidoptera: Crambidae), corn earworm (Lepidoptera: Noctuidae), and damaged kernels in sweet corn ears.

Late-season infestations of European corn borer, Ostrinia nubilalis (Hübner), and corn earworm, Helicoverpa zea (Boddie), were sampled to develop binomial sequential sampling plans for larval infestations and damaged kernels in sweet corn, Zea mays L., ears, near harvest. Fields were sampled to obtain a range of larval densities likely to be encountered over a range of infestation levels and field conditions. Binomial sampling plans were developed for O. nubilalis larvae, H. zea larvae, O. nubilalis, and H. zea larvae combined, and for damaged sweet corn kernels. Observed densities ranged from 0.01 to 4.40 larvae per ear for O. nubilalis, 0.005-1.62 larvae per ear for H. zea, and 0.004-36.12 damaged kernels per ear. Results of resampling analyses, based on the proportion of ears infested with one or more larvae, or damaged kernels, indicated an average sample size of 34-37 ears was necessary to classify whether larval infestations, or the incidence of damaged kernels, exceeded 5%. Two operating characteristic curves are presented for each of the four sampling plans. Initial results, with upper bounds of 0.10, and alpha (type I) and beta (type II) error rates at 0.10 and 0.05, respectively, resulted in a 90% probability of making the correct management decision at infestation levels >10%. To improve performance of the sampling plans, we modified the binomial plans by reducing the upper bound to 0.075, while maintaining the same error rates. This plan resulted in a higher probability (>95%) of making the correct management decision to reject a sweet corn load when infestation levels are >10%.

Animals↗

PubMed2006

Comparative susceptibility of European corn borer, southwestern corn borer, and sugarcane borer (Lepidoptera: Crambidae) to Cry1Ab protein in a commercial Bacillus thuringiensis corn hybrid.

One field strain each of the European corn borer, Ostrinia nubilalis (Hübner); southwestern corn borer, Diatraea grandiosella Dyar; and sugarcane borer, Diatraea saccharalis (F.); were collected from cornfields in northeastern Louisiana. Susceptibilities of the field strain and a corresponding laboratory strain of the three borer species to Cry1Ab protein in DK69-70 Bacillus thuringiensis (Bt) corn hybrid were determined by exposing neonates to intact leaf tissues from whorl stage plants or by feeding neonates or third instars on a meridic diet treated with different concentrations of Cry1lAb protein extracted from Bt corn leaves. Mortality and growth of larvae were evaluated after 2 and 4 d posttreatment in the bioassays by using intact leaf tissues or after 7 d in the bioassays by using diet incorporating Cry1Ab protein. D. saccharalis was the least susceptible species to Cry1Ab protein among the three species, followed by D. grandiosella, whereas O. nubilalis was most susceptible. The 2-d mortality of D. saccharalis neonates on intact Bt leaf tissues was lower than that of O. nubilalis and D. grandiosella. All neonates of O. nubilalis were killed on the diet treated with Cry1Ab protein at 0.5 and 1 mg/kg. The mortality of D. grandiosella was > 75% at 1 mg/kg, but it was < 6% for D. saccharalis at 1 mg/kg. The LC50 values of D. saccharalis were 3- and 11-fold higher than those of D. grandiosella and O. nubilalis, respectively. The LC90 values of D. saccharalis were 8- and 32-fold higher than those of D. grandiosella and O. nubilalis, respectively. Larval growth of the three species on Cry1Ab-treated diet was inhibited, but the inhibition was greater for O. nubilalis and D. grandiosella than for D. saccharalis. The lower susceptibility of D. saccharalis to Cry1Ab protein suggests that it is necessary to verify if a high-dose Bt corn for O. nubilalis and D. grandiosella is also a high dose for D. saccharalis.

Analysis of Variance↗

PubMed2002

Management of corn leafhopper (Homoptera: Cicadellidae) and corn stunt disease in sweet corn using reflective mulch.

Plastic reflective mulches significantly reduced populations of corn leafhopper, Dalbulus maidis (DeLong & Wolcott), adults and the incidence of corn stunt disease caused by Spiroplasma kunkelii (CSS) in late planted sweet corn (Zea mays L.). The reflective mulches were more effective than were either foliar or soil applied insecticides in managing both the leafhopper and the pathogen it transmits. Yields of marketable ears were 1.5 to 2 times greater in reflective mulch plots than from fallow plots. This was due to larger ears (individual ear weight and length) rather than an increase in the number of ears. The use of reflective mulches provides an alternative strategy to insecticides in the management of both D. maidis and corn stunt disease. Such a strategy may prove useful to growers in Latin America and to limited resource growers and organic growers in the United States who wish to grow corn without the use of insecticides.

Animals↗

PubMed2005

Calcium, phosphorus, and amino acid digestibility in low-phytate corn, normal corn, and soybean meal by growing pigs.

Nine growing barrows were equipped with a T-cannula in the distal ileum and used to determine apparent ileal (AID) and apparent total-tract digestibility (ATTD) coefficients of Ca and P in low-phytate corn, normal corn, soybean meal, and in diets where soybean meal was mixed with low-phytate corn or normal corn. The AID and the standardized ileal digestibility coefficients (SID) of CP and AA also were determined. The animals (initial BW = 29.3 +/- 1 kg) were allotted to a 9 x 9 Latin square with nine diets and nine periods. Three diets contained low-phytate corn, normal corn, and soybean meal as their sole source of CP, AA, Ca, and P, respectively. Three additional diets were identical to these diets except that limestone and monosodium phosphate were added. Two diets contained low-phytate corn or normal corn and soybean meal, limestone, and monosodium phosphate, and the final diet was a N-free diet. The AID and ATTD of Ca were higher (P < 0.05) for low-phytate corn than for normal corn (70.0 and 69.1% vs. 47.4 and 49.6%, respectively). The AID and ATTD for Ca in soybean meal (50.9 and 46.7%, respectively) did not differ from values for normal corn but were lower (P < 0.05) than for low-phytate corn. The AID and ATTD for P from low-phytate corn (56.5 and 54.5%, respectively) were greater (P < 0.05) than from normal corn (28.3 and 28.8%, respectively), whereas soybean meal had intermediate AID and ATTD for P (37.2 and 38.0%, respectively). The AID and ATTD of P increased (P < 0.05) when monosodium phosphate was added to normal corn (44.9 and 49.8%, respectively) and soybean meal (49.6 and 46.2%, respectively), but adding monosodium phosphate to low-phytate corn, did not alter either AID (49.7%) or ATTD (50.7%) of P. No differences between AID and ATTD for Ca or P within the same diet were observed. The AID of Arg, Asp, Gly, Ile, Lys, Phe, Thr, and Val were greater (P < 0.05) in low-phytate corn than in normal corn. The AID of all AA in soybean meal were greater (P < 0.05) than in both types of corn, with the exception of Ala, Cys, Leu, and Met. The SID of Lys, Phe, and Thr were higher (P < 0.05) in low-phytate corn than in normal corn. Because low-phytate corn has a higher digestibility of Ca and P, less inorganic Ca and P need to be supplemented to diets containing low-phytate corn than to those containing normal corn, and P excretion may be decreased when low-phytate corn is used in the diet.

Amino Acids↗

PubMed2004

Management of feeding damage and survival of southwestern corn borer and sugarcane borer (Lepidoptera: Crambidae) with Bacillus thuringiensis transgenic field corn.

The efficacy of transgenic corn hybrids expressing an insecticidal Bacillus thuringiensis (Bt) delta-endotoxin from different transformation events was evaluated in field corn, Zea mays L., against the southwestern corn borer, Diatraea grandiosella Dyar, and sugarcane borer, Diatraea saccharalis (F.). Susceptibilities of neonates and third instars were determined on Bt and non-Bt corn plants (V6 and R1 stages) in field plots and corn leaf tissue feeding exposure in laboratory bioassays. Bt corn hybrids associated with MON810 and CBH351 transformation events sustained significantly less injury by southwestern corn borer and sugarcane borer during mid-whorl stage infestations compared with their respective non-Bt hybrid equivalents. Southwestern corn borer and sugarcane borer feeding injury to ear leaf-sheath and husk tissues during the silking stage of corn was significantly reduced in MON810 and CBH351 Bt corn compared with their respective non-Bt hybrids. However, resistance levels to feeding injury in Bt hybrids associated with the MON810 event were significantly higher than that in the hybrid associated with the CBH351 event. Southwestern corn borer and sugarcane borer caused more feeding injury to husk tissue than to ear leaf-sheath tissue in both Bt and non-Bt hybrids infested during the silking stage. Laboratory performance of the MON810 event against southwestern corn borer and sugarcane borer varied among hybrids associated with the same event. Third instars of southwestern corn borer were highly susceptible to MON810 Bt corn hybrids in leaf tissue experiments. However, sugarcane borer larvae were susceptible to the MON810 event only in one of the Bt hybrids evaluated. Sugarcane borer mortality was significantly lower after 96 h of feeding exposure on CBH351 Bt corn leaf tissue than on MON810 Bt corn leaf tissue. Plant resistance to southwestern corn borer and sugarcane borer increased as plants matured, independent of the presence of a Bt construct. These results are essential to estimate the importance of Bt transgenic corn in areas of southern United States and other areas where mixed populations of southwestern corn borer and sugarcane borer are predominant and cause severe damage to corn production.

Animals↗

PubMed2005

Optimal wet corn gluten and protein levels in steam-flaked corn-based finishing diets for steer calves.

A feeding trial evaluated the hypothesis that wet corn gluten feed would improve growth performance of cattle fed steam-flaked corn-based finishing diets and supply required degradable intake protein (DIP). The trial used 360 steer calves (initial BW = 288 +/- 11 kg) housed in 36 pens for 166 d in an incomplete 4 x 3 factorial arrangement of treatments. Pens of steers were assigned to treatments according to a completely randomized design (four replicates per treatment combination). Treatments were wet corn gluten feed (0, 20, 30, or 40% of dietary DM) and CP (13.0, 13.7, or 14.4% of dietary DM) via supplemental urea as DIP. The 0% wet corn gluten feed treatment included only the 13.7% CP diet, and the 40% wet corn gluten feed treatment included only the 13.7 and 14.4% CP diets. Final dietary DIP concentration was 9.0% for 0% wet corn gluten feed; 8.7, 9.5, and 10.2% for 20% wet corn gluten feed; 9.0, 9.7, and 10.3% DIP for 30% wet corn gluten feed; and 10.0 and 10.6% for 40% wet corn gluten feed. Hot carcass weight, ADG, DMI, and G:F responded quadratically (P < or = 0.05) to wet corn gluten feed. The 20, 30, and 40% wet corn gluten feed treatments increased ADG by 7, 6, and 3% and increased DMI by 4, 5, and 5%, respectively, relative to the 0% wet corn gluten feed treatment. Feed efficiency was 102, 101, and 98% of the 0% wet corn gluten feed treatment for 20, 30, and 40% wet corn gluten feed, respectively. Hot carcass weight, ADG, and G:F increased linearly (P < or = 0.05) in response to increased DIP. Nonlinear analysis for DIP over the combined 20 and 30% wet corn gluten feed treatments indicated a DIP requirement of 9.6% of DM for ADG and 9.2% of DM for G:F, corresponding to 14.6 and 14.3% CP for 20% wet corn gluten feed and 14.8 and 14.5% CP for 30% wet corn gluten feed, respectively. Fat thickness, marbling, LM area, and USDA yield grade were not affected (P = 0.12 to 0.99) by wet corn gluten feed or CP. These results show that the inclusion rate of wet corn gluten feed for maximizing ADG and G:F in steam-flaked corn-based finishing diets is approximately 20% of DM. The DIP requirement determined in this trial averaged 9.4% of DM.

Animal Feed↗

PubMed2002

Biotechnology and the European corn borer: measuring historical farmer perceptions and adoption of transgenic Bt corn as a pest management strategy.

A 3-yr, multi-state survey of farmers who had planted transgenic Bacillus thuringiensis (Bt) corn was conducted to evaluate perceptions of Bt corn performance and its utility as a management option for European corn borer, Ostrinia nubilalis (Hübner). A questionnaire was sent to farmers in Illinois, Iowa, Kansas, Minnesota, Nebraska, and Pennsylvania who had grown Bt corn during the growing seasons of 1996, 1997, or 1998. There were 7,427 usable questionnaires returned with the following response percentages: 1996 (42.1%), 1997 (35.0%), and 1998 (22.6%). Adoption rates, based on percentage of acreage planted to Bt corn, increased dramatically from 1996 (10.5%) to 1998 (40.7%). The states growing the highest percentage of Bt corn were Minnesota, Iowa, and then Nebraska However, Illinois, was adopting Bt corn at the fastest rate. Historical use of insecticides did not influence the adoption of Bt corn. In addition, of those farmers who used insecticides to control European corn borer, the percentage that decreased their use of insecticides nearly doubled from 13.2% (1996) to 26.0% (1998) over this 3-yr period. The primary reason farmers planted Bt corn was to eliminate the yield loss caused by European corn borer. Scouting for European corn borers decreased from 91% (scouting 2.2 times a year) in 1996 to 75% (scouting 1.8 times a year) in 1998. The percentage of farmers not scouting for European corn borers increased from 9.6% (1996) to 25% (1998). Most farmers believed yields of Bt hybrids were either similar to or greater than the yields of non-Bt hybrids. Minnesota farmers perceived the greatest yield advantages. Farmers are becoming more aware of insect resistance management guidelines; however, they also clearly show preferences for having the flexibility to use different spatial plantings of Bt and non-Bt corn. Finally, after having planted Bt corn and obtained excellent control of European corn borer, most farmers believed that this insect had been causing more yield loss than they previously had suspected in their non-Bt corn. The data represented here provide an historical foundation for how transgenic Bt corn was used by farmers during the first 3 yr of commercial availability, their initial perceptions on the performance of this technology, and their attitudes regarding management of the European corn borer.

Animals↗