• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.1001-1008
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• 2005

This study examined the effect of corn processing with varying rumen undegradable protein (RUP) on feed intake, milk yield, its composition and, blood characteristics in Holstein cows during the transitional period (21 days pre partum to 21 days post partum). Twenty Holstein cows were randomly assigned to four diets (five cows/diet), ground corn with 30 % RUP (GCR30), ground corn with 40 % RUP (GCR40), flaked corn with 30 % RUP (FCR30), and flaked corn with 40 % RUP (FCR40). The processed corn with varying RUP was fed in total mixed rations (TMR) to cows. Dry matter intake (DMI) was higher with 40 % RUP diet than with 30 % RUP diet, resulting in higher protein and energy intake by cows during pre and post partum (p＜0.05). However, it was not affected by corn processing during pre and post partum. Similarly milk yield was higher with 40 % RUP diet than with 30 % RUP diet. and milk yield was affected by corn processing at RUP 30 % level. Corn processing did not affected the milk fat and protein contents in dairy cows. The concentration of blood non esterified fatty acid (NEFA) were effected by RUP level with flaked corn, however, it was non-significant with RUP levels when given with ground corn. It is concluded that increasing RUP from 30 % to 40 % in iso-nitrogenous diet could increase milk yield in dairy cows during the transitional phase.

• Journal of Practical Agriculture & Fisheries Research
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• v.3 no.1
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• pp.132-141
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• 2001

This study was conducted to determine effects of whole and processed corns on attachment characteristics of rumen microbes in Hanwoo. Whole corn(WC) was processed into four different types; ground corn(GC), cracked corn(CC), flaked corn(FC), and soaked corn(SC). After each processed corns was incubated in the rumen of Hanwoo for 12 h and 24 h, attachment characteristics of rumen microbes and morphological changes of feed substrates was examined by utilizing scanning electron microscopy(SEM). In this study, the treatment group of GC and CC showed the highest in the attachment of rumen microbes. On the other hand, microbial attachments to the starch particle of WC and SC were hardly detected. However, with the increase of incubation time the surface of WC and SC was covered by many microbes, resulting in enhancing the surface degradation.

• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.757-768
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• 2002

These study were conducted to determine the effects of a whole or steam-flaked corn based diet on rumen microbial fermentation in vitro and ruminal metabolism in the Korean Native Goat(KNG) in vivo. The experiments consisted of two dietary treatments: control, steam-flaked corn(SFC) based diet(80%) + rice straw mixed(20%)(SFCR); 100% whole corn based diet(WC). The first experiment was conducted to investigate the effect of whole corn on ruminal metabolism in vitro for 0 to 48 h. pH values were optimally maintained during incubation time, and were not significantly different between treatments. Gas production of SFCR was significantly higher than WC(p<0.01). $NH_3$-N concentration tended to increase for WC, but not significantly different between treatments. The mean value of total volatile fatty acid concentration of WC was significantly lower than SFCR(p<0.01), but SFCR and WC linearly increased as the time of incubation approached 48 h. Mean value of acetate concentration of SFCR was significantly higher than WC(p<0.01). Propionate concentration of WC for the total incubation time was significantly higher than SFCR(p<0.01). The digestibility of dry matter was not significantly different between treatments, but SFCR was somewhat higher than WC. The second experiment was conducted to effect of whole shelled corn based diet on rumen metabolism in KNG. pH values tended to decrease through all treatments. There was not a significantly difference between treatments. Microbial protein yield of SFCR was significantly higher than WC(p<0.01). $NH_3$-N concentration of WC was significantly (p<0.01) higher than SFCR. Total VFA and propionate concentration of WC was significantly higher than SFCR(p<0.01), but acetate concentrate of WC was not significantly higher than SFCR. The mean value of total lactate concentration was significantly(p<0.01) different but the value of SFCR and WC were lower than the average concentration of acidosis. In sacco DM disappearance rate of SFC was significantly(p<0.01) higher than WC.

• Journal of Life Science
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• v.18 no.11
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• pp.1561-1569
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• 2008

This study was conducted to investigate the effects of steam flaking of corn grains on in situ dry matter degradability in the rumen and contents of mycotoxins (aflatoxin, ochratoxin) during storage. Yellow dent corns imported from USA and India were flaked, and stored for 8 weeks under the standard temperature and pressure (STP; $25^{\circ}C$/ 1 atm.). Experimental treatments were composed of four corn grains (untreated-USA corn, USCW; steam flaked-USA corn, USCF; untreated-India corn, IDCW; steam flaked-India corn, IDCF) with 4 replications according to 9 storage periods (0, 1, 2, 3, 4, 5, 6, 7, 8 week). Two ruminally cannulated Holstein bulls were used for in situ trial. Pathogen contamination trial was performed by comparing the mycotoxin contents in corns during storage periods. Dry matter disappearance rate in the rumen was about 3.0 to 44.1% higher (P<0.05) for USCW than IDCW, but was not difference between USCF and IDCF. With steam flaking of corn, dry matter degradability in the rumen was significantly (P<0.05) increased in corn from India, but was not affected in corn from USA. Aflatoxin content was very low level in corns from USA and steam flaked corns, but was higher than the tolerance limit of domestic aflatoxin content regulation when IDCW was stored over 6 week under STP. Ochratoxin content was low level in all treatments. From above results, it is reasonable that the corn imported from India might be flaked for enhance the ruminal DM degradability and safe from aflatoxin pathogen.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.6
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• pp.859-863
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• 2018

Objective: Since very little information exists about the topic; in this experiment we compare, in a long-term finishing program, the growth-performance responses and carcass characteristics of Holstein steers where non-structural carbohydrate concentration of the diet is reduced from 64% to 51% (dry matter basis). Methods: Sixty Holstein steer calves ($129{\pm}2.2kg$) were blocked by initial weight into five groups and randomly assigned within weight groupings to 10 pens. Calves were fed with a steam-flaked corn-based finishing diets containing 51% higher fiber (HF) or 64% lower fiber (LF) nonstructural carbohydrates. Non-structural carbohydrates concentrations were manipulated substituting dried distiller grain with solubles and alfalfa hay for flaked corn. Cattle were weighed every 112 days and at the end of the experiment (day 308) when the cattle were harvested and carcass characteristics were evaluated. Results: Steers fed the HF diet showed improvement (8.8%) in average daily gain (ADG) during the initial 112-d period. This effect was followed by a numerical trend for greater ADG throughout the remainder of the study so that overall ADG tended to be greater (4.9%, p = 0.06) for the HF than for LF. There were no treatment effects on dry matter intake. Gain efficiency and estimated dietary net energy (NE) were greater 8.3% and 5.2%, respectively for HF during the initial 112-d period. Overall (308-d) gain efficiency and estimated dietary NE were similar for both dietary treatments. However, due to differences in tabular dietary NE, the ratio of observed:expected dietary NE tended to be greater (4.1%, p = 0.06) for the HF vs LF diet. There were no treatment effects on carcass characteristics except for a tendency toward a slightly greater (0.5%, p = 0.09) estimated carcass yield. Conclusion: Reducing the non-structural carbohydrate concentration of a conventional steam-flaked corn-based growing finishing diet for Holstein steers can effectively enhance growth performance, particularly during the early growing and late finishing phases.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.491-500
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• 2010

Three experiments were conducted to investigate the effects of polyurethane coated urea on in vitro ruminal fermentation, ammonia release dynamics and lactating performance of Holstein dairy cows fed a steam-flaked corn-based diet. In Exp. 1, a dual-flow continuous culture was run to investigate the effect of polyurethane coated urea on nutrient digestibility, rumen fermentation parameters and microbial efficiency. Three treatment diets with isonitrogenous contents (13.0% CP) were prepared: i) feedgrade urea (FGU) diet; ii) polyurethane coated urea (PCU) diet; and iii) isolated soy protein (ISP) diet. Each of the diets consisted of 40% steam-flaked corn meal, 58.5% forages and 1.5% different sources of nitrogen. PCU and FGU diets had significantly lower digestibility of NDF and ADF (p<0.01) than the ISP diet. Nitrogen source had no significant effect (p = 0.62) on CP digestibility. The microbial efficiency (expressed as grams of microbial N/kg organic matter truly digested (OMTD)) in vitro of the PCU diet (13.0 g N/kg OMTD) was significantly higher than the FGU diet (11.3 g N/kg OMTD), but comparable with the ISP diet (14.7 g N/kg OMTD). Exp. 2, an in vitro ruminal fermentation experiment, was conducted to determine the ammonia release dynamics during an 8 h ruminal fermentation. Three treatment diets were based on steam-flaked corn diets commonly fed to lactating cows in China, in which FGU, PCU or soybean meal (SBM) was added to provide 10% of total dietary N. In vitro $NH_3-N$ concentrations were lower (p<0.05) for the PCU diet than the FGU diet, but similar to that for the SBM diet at all time points. In Exp. 3, a lactation trial was performed using 24 lactating Holstein cows to compare the lactating performance and blood urea nitrogen (BUN) concentrations when cows were fed PCU, FGU and SBM diets. Cows consuming the PCU diet had approximately 12.8% more (p = 0.02) dietary dry matter intake than those consuming the FGU diet. Cows fed the PCU diet had higher milk protein content (3.16% vs. 2.94%) and lower milk urea nitrogen (MUN) concentration (13.0 mg/dl vs. 14.4 mg/dl) than those fed the FGU diet. Blood urea nitrogen (BUN) concentration was significantly lower for cows fed the PCU (16.7 mg/dl) and SBM (16.4 mg/dl) diets than the FGU (18.7 mg/dl) diet. Cows fed the PCU diet had less surplus ruminal N than those fed the FGU diet and produced a comparable lactation performance to the SBM diet, suggesting that polyurethane coated urea can partially substitute soybean meal in the dairy cow diet without impairing lactation performance.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.127-137
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• 2024

This study was conducted to investigate effect of corn flake and corn ground on nutrient digestibility and fermentation characteristics of rumen in Hanwoo. The animals used were three Hanwoo cows implanted with ruminal fistula. Corn were categorized in 2 groups based on the corn processing method: Ground and Flake. The rumen digestibility of dry matter, starch, nitrogen free extract and non fiber carbohydrates were increased in flake compared to ground from 3 to 24 hours of incubation(P<0.05). The pH of rumen was lower in the flaked treatment than ground treatment at 3 hours after incubation, but average pH was no significantly difference between treatments. The average acetic acid, propionic acid and butyric acid were significantly increased in the flaked treatments compared to the ground treatment (P<0.05). Thus, flake processing can improve the carbohydrate availability of corn in the rumen and increase feed value.

• Journal of Practical Agriculture & Fisheries Research
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• v.3 no.1
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• pp.116-131
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• 2001

Experiments were conducted to determine effects of whole and processed corns on in situ disappearance rates of nutrients in the rumen and in vitro degradability of dry matter by rumen microorganisms. Whole corn(WC) was processed into four different types; ground corn(GC), cracked corn(CC), flaked corn(FC), and soaked corn(SC). In the in situ experiment, the rate of ruminal DM disappearance after 48 hour incubation was highest in GC(76.1%) and lowest in WC and SC(12% ; P<0.01). The rate of ruminal CP disappearance after 48 hour incubation was highest in GC and CC(48 and 38%, respectively; P<0.01). The rate of ruminal OM disappearance after 48 hour incubation was highest in GC(76.14%) and lowest in WC and SC(11.82 and 12.26%, respectively; P<0.01). In the in vitro experiment, the two-stage incubation technique was used to measure digestibilities of whole and processed corns. The digestibility of DM was higher in GC, CC and FC(86.95, 85.84 and 82.29%, respectively) than in WC(15.36%; P<0.01).

• Journal of Life Science
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• v.19 no.1
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• pp.65-74
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• 2009

The objective of this study was to examine the effects of steam flaking treatment of corn grains imported from USA and India on in vitro gas production, microbial growth and contents of aflatoxin $B_1$ and ochratoxin A. Each treatment was composed of total 4 treatments including (1) USCW (US com-whole type), (2) USCF (US corn-flaked type), (3) IDCW (India corn-whole type) and (4) IDCF (India orn-flaked type) with 4 replications $\times$ 6 incubation times (3, 6, 9, 12, 18 and 24 hr). Mycotoxin (aflatoxin $B_1$ & ochratoxin A) contents in test corns tended to increase gradually with increasing logistics periods from the harbor, hopper, silo to processing line. The contents of aflatoxin $B_1$ in India corn (IDCW) and US corn (USCW) were 11.71 and 1.78 ppb, respectively when measured at the hopper. After steam flaking, both contents of aflatoxin $B_1$ in USCW and IDCW were 0.00 ppb. It means that Aspergillus flavus could be decreased by steam flaking. However, this trend was not observed in ochratoxin content. The gas production rate of USA corns (USCW & USCF) was significantly (p<0.05) higher than India corns (IDCW & IDCF), and that of steam flaked corns (USCF & IDCF) was higher $1.5{\sim}2%$ than whole corns (USCW & IDCW) after 3 hr incubation in in vitro experiment. pH value was optimally maintained for microbial growth during whole incubation times with the value of 6.05 to 6.54, and was not significantly different between treatments, but USCF was somewhat lower than other treatments. pH value decreased following 12 hr of incubation but gas production increased rapidly during the same period. In addition, in vitro microbial growth rates also increased with up to 18 hr of incubation period, thereafter experienced a decrease with extended incubation time. In conclusion, US corn was superior to India corn by origin based on the results of in vitro and mycotoxin contents. And steam flaking process of imported corns tended to decrease mycotoxin contents such as aflatoxin $B_1$ and ochratoxin A as well as improve in vitro gas production and microbial growth rates.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.547-554
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• 2008

In performance, digestibility and slaughter trials, a total of forty five male weaned lambs were used to examine the effects of monensin and live yeast supplementations on growth performance, nutrient digestibility, carcass characteristics and ruminal fermentation parameters when the lambs were fed steam-flaked corn-based diets. Animals were allotted to one of three treatment diets in a completely randomized design. The three treatment diets were: (1) basal diet (CON) with steam-flaked corn as a sole grain source, (2) basal diet supplemented with monensin (MO), and (3) basal diet supplemented with live yeast (LY). Total average daily intake (ADI) was unaffected by MO and LY supplementations. LY supplementation increased (p<0.05) average daily gain (ADG) by 13.1% compared with the CON diet. Both MO and LY supplementations resulted in a significant improvement (p<0.05) of feed efficiency over the CON diet (4.47, 4.68 vs. 5.05). Hemicellulose digestibility was higher (p<0.05) for lambs in the LY supplementation group (62.4%) as compared with the CON group (55.7%), but no differences were observed in digestibilities of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF). All carcass traits were not influenced by dietary supplementations. Ruminal pH in lambs fed the LY supplemental diet was more stable than that with the CON diet (6.57 vs. 6.17). Neither MO nor LY supplementation influenced the concentration of ruminal ammonia-N and total volatile fatty acid (VFA), and molar percentages of individual VFA. Plasma urea-N concentration was decreased (p<0.05) by MO and LY supplementations, while plasma ${\beta}$-hydroxybutyrate (BHBA), glucose and other blood parameters were unaffected. In conclusion, while both MO and LY supplementations had a positive impact on feed efficiency and LY supplementation stabilized ruminal pH and improved fiber utilization, none of the supplements had the capacity to significantly enhance the carcass characteristics.