• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.4
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• pp.308-314
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• 2017

This study was conducted with two ruminally cannulated Holstein steers to examine the effect of micronized and steam flaked corn on ruminal fermentation characteristics. The in situ dry matter degradability after 48 h incubation was the highest (P<0.05) at micronized corn (2.5 mm thickness) compared with steam flaked corn treatments. The steam flacked corn (3.3 mm thickness) was degraded lower (P<0.05) than the 2.9 and 3.1 mm thickness of steam flacked corn. Effective dry matter degradability and the rate of constant were the highest (P<0.05) at micronized corn (2.5 mm thickness) compared with steam flaked corns as well. The in vitro dry matter degradability after 48 h incubation was tended to higher (P=0.088) at micronized corn (2.5 mm thickness) than steam flaked corns, whereas there is no significantly difference between steam flaked corn treatments. Total volatile fatty acid concentration was higher at steam flaked corn (2.9 mm thickness) than micronized corn (2.5 mm thickness) and steam flaked corn (3.1 and 3.3 mm thickness). The acetate : propionate ratio was the highest (P=0.008) at steam flaked corn (2.9 mm thickness) and the lowest (P=0.008) at micronized corn (2.5 mm thickness). Total gas and methane production after 48h ruminal incubation was the highest (P=0.001) at micronized corn (2.5 mm thickness) compared with steam flaked corns. According to these results, the thickness of steam flaked corn as resulted corn processing is believed to do not affect methane production. However, further study is needed to better understand the present results to verify the correlation between corn processing method and their thickness on methane production using the same thickness corns by difference processing methods.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.708-712
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• 2002

Effects of unprocessed (whole) or steam-flaked corn with or without enzyme additives on in vivo nutrient digestibilities and distribution of corn particles in the feces of Holstein steers were determined in a $4{\times}4$ Latin square experiment using four Holstein steers fed the diets containing 1) whole corn without enzyme additive, 2) whole corn with enzyme additive, 3) flaked corn without enzyme additive, or 4) flaked corn with enzyme additive. With regard to nutrient digestibilities such as DM, CP, CF, NFE, NDF, and ADF, no significant differences were detected among treatments, and also the nutrient digestibilities were not affected by the addition of enzyme additive. When distribution of corn particles in the feces was examined, there were no significant differences in the amount of 2, 8 mm and total corn particles. However, feeding flaked corn resulted in less corn particles (4 mm) in the feces than feeding whole corn (p<0.05). There were no significant differences in amounts of corn particles in the feces due to the addition of enzyme additive.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.851-858
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• 2002

This study was conducted to determine effects of whole (intact), coarsely-ground (4 mm), finely-ground (1 mm), steam-flaked and steam-flaked-ground (1 mm) corns on in vitro and in situ DM digestibilities and also in vitro fermentation characteristics. After 48 h incubation, in vitro dry matter digestibilities of whole, steam-flaked, coarsely-ground, steam-flaked-ground, and finely-ground corns were 6.79, 61.68, 76.48, 85.72 and 90.31%, respectively. Steam-flaked-ground corn showed the highest digestibility until 24 h incubation (p<0.01). After 48 h incubation, pH of whole corn decreased with a small range. However the values of pH of other media significantly decreased (p<0.01). The gas productions of finely-ground and steam-flaked-ground corns were higher than those of the other corns (p<0.01). After 24 h incubation, $NH_3$-N concentration of finely-ground and steam-flaked-ground corns increased rapidly. Total VFA was the highest in finely-ground corn, followed by steam-flaked-ground, steam-flaked, coarsely-ground and whole corns. Incorporating steam-flaked corn resulted in the highest propionate concentration (p<0.01) and the lowest acetate : propionate value (p<0.05). Finely-ground corn showed the highest in situ DM digestibility throughout the incubation period (p<0.01), followed by coarsely-ground, steam-flaked and whole corns, respectively. Overall, DM of whole corn was merely digested in vitro as well as in situ.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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• pp.1573-1579
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• 2019

Objective: The research was conducted to determine the digestible (DE) and metabolizable energy (ME) contents as well as the apparent total tract digestibility (ATTD) of nutrients in corn, waxy corn and steam-flaked corn fed to growing pigs. Methods: Eighteen growing pigs with initial body weight of $15.42{\pm}1.41kg$ were randomly allotted to three diets including a corn diet, a waxy corn diet and a steam-flaked corn diet in a completely randomized design. Each treatment contained six replicates. The experiment lasted for 12 days, which comprised 7-d adaptation to diets followed by a 5-d total collection of feces and urine. The energy contents and the nutrient digestibility in three ingredients were calculated using direct method. Results: Compared to normal corn, both the amylose and dietary fiber contents in waxy corn were numerically lower, but the starch gelatinization degree was numerically greater. Moreover, the DE and ME contents as well as the ATTD of neutral detergent fiber and acid detergent fiber (ADF) in waxy corn were significantly greater (p<0.05) than those in normal corn when fed to growing pigs. Furthermore, the steam-flaked corn had greater (p<0.05) DE and ME contents, and ATTD of ether extract and ADF compared to normal corn. Conclusion: Both variety and processing procedure have influence on chemical compositions, energy contents and nutrient digestibility of corn. The waxy corn and steam-flaked corn had greater degree of starch gelatinization and DE and ME contents compared to normal corn when fed to growing pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.793-799
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• 2002

Four feeds, three concentrates (rice bran, soybean meal and flaked corn) and one forage (corn silage) were incubated in four ruminally fistulated Holstein steers over three one week periods in a 3${\times}$4 incomplete latin square design where steers served as blocks and feeds as treatment. The objectives of the study were to investigate in situ DM, N and P degradability characteristics of feeds in order to assess availability of these nutrients by ruminants. In each period, all feeds were incubated in quadruplets (corn silage in triplicates) in the rumen of each steer in a reverse order for 3, 6, 9, 12, 18, 24 and 48 h. The DM 'a' fraction was higher and lower (p<0.001) in corn silage and rice bran respectively. Although corn silage contained the lowest (p<0.01) DM 'b' fraction, flaked corn contained the highest. Rate of DM degradation of flaked corn and corn silage were half (p<0.05) of the rate of DM degradation of either rice bran or soybean meal. Potential or effective DM degradability (p<0.05 to 0.001) at various passage rates were the lowest for rice bran and the highest for soybean meal. Corn silage N 'a' and 'b' was the highest and lowest, respectively (p<0.01). N 'c' of corn silage and rice bran was higher (p<0.001) than other feeds. Potential N degradability was the lowest in flaked corn (p<0.05). P 'a' was high (p<0.01) for corn silage and rice bran. P 'b' fraction was very high (p<0.001) in soybean meal but was absent in corn silage. Availability of DM (p<0.01 or 0.001), N (p<0.001) and P (p<0.05) differed between feeds at various passage rates except P availability at k=0.02 per h (p>0.05). The results demonstrate that the availability of DM, N and P by ruminants depends on feed as well as categories of animal.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.421-432
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• 2003

The objective of this study was to examine the effects of processing methods of corn grains on protein and starch degradability in the rumen by three ruminally cannulated dry Holstein cows. The corns for these experiments were untreated; whole corn L(density; 660 g/$\ell$), whole corn H(density; 740 g/$\ell$), and treated by four different types: Ground corn, 3.8 mm, 2.8 mm, and 1.5 mm flaked corn. The results obtained were summarized as follows: For 48 hrs, the protein degradabilities were high in order, ground corn, 1.5 mm, 2.8 mm, and 3.8 mm flaked corn(82.6, 76.5, 64.5, and 33.9%, respectively). Flaked corn grains were degraded lower than ground corn. However, as increasing the processing degree of flaking, the protein degradabilities, from 4 hrs to 48 hrs, were increased. The starch degradabilities on 48 hrs were higher in 1.5 and 2.8 mm flaked corns, ground corn, 3.8 mm flaked corn(99.1, 91.5, 89.5, and 68.9%, respectively) than whole corn L(32.0%) and whole corn H(20.5%)(P<0.05). By increasing the processing degree of flaking, the protein degradabilty between 2.8 mm and 3.8 mm was increased significantly from 68.9% to 91.5%, however, that of 1.5 mm flaked corn, processed thinner, tended to be increased slightly, but was not significantly different. From 12 hrs to 24 hrs, whole corn L was degraded little more than whole corn H in starch, was not significantly different. However, after 48 hr incubation in the rumen, whole corn L was degraded more 50% than whole corn H(P<0.05). The value of degradation parameter “a” of protein was lower in all flaked corns than in ground corn. In contrast, the value of degradation parameter “a” of starch was significantly higher in all flaked corns than in ground corn(P<0.05). It seemed that by flaking the corn grains, starch particles were gelatinized, and then, starch was degraded more rapidly, while protein was degraded more slowly. Referring to these kinds of physical characteristics of grain sources in ruminal degradabilities, it is possible to synchronize the fermentation of nitrogen and carbohydrate sources, in formulating the cattle diets.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.433-442
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• 2003

The objective of these studies were to examine the effects of processing methods of corn grains on in vitro dry matter digestability and in sacco degradability in the rumen by three ruminally cannulated dry Holstein cows. The corns for these experiments were untreated; whole corn L(density; 660 g/$\ell$), whole corn H(density; 740 g/$\ell$), and treated by four different types: Ground corn, 3.8 mm, 2.8 mm, and 1.5 mm flaked corns. The results obtained were summarized as follows: The DM degradabilities, after 48 hr incubation by in sacco method, were the highest(94.4, 88.0 and 87.0%, respectively) in 1.5 mm flaked corn, ground corn, and 2.8 mm flaked corn. The 3.8 mm flaked corn was degraded significantly lower than these. Until 12 hr incubation, whole corn L tended to be degraded little more than whole corn H, was not significantly different. However, after 24 hr incubation, the significant differences between whole corn L and whole corn H were shown(P<0.05). The DM digestabilities by in vitro digestion were the highest for 1.5 mm flaked corn and ground corn(92.3 and 91.2%, respectively)(P<0.05), followed by 2.8 mm and 3.8 mm flaked corn(83.9 and 83.4%, respectively), tended to be similar to those by in sacco method. Whole corn L was digested twice more rapidly than whole corn H. Summarizing the experimental data, compared with unprocessed corns, the flaked corns were significantly increased in the degradabilities of dry matter in the rumen. In addition, as increasing the flaking degree of corn, the degradabilities of dry matter were significantly improved. Referring to these kinds of physical characteristics of grain sources in the ruminal degradabilities, it is believed to be possible to optimize the environment of the fermentation in the rumen.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.4
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• pp.470-473
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• 2000

The experiment was carried out to evaluate the effect of varying levels of flaked com abomasally infused on energy metabolism and nitrogen metabolism in fattening steers. The starch levels of flaked corn of abomasally infused were 0, 300, 600 and 900 g/d. Four mature fattening steers fitted with permanent abomasum cannulas were allocated to a $4{\times}4$ Latin square design were fed at 1.2 maintenance requirement a basal diet of Chinese wildrye (Aneurolepidium Chinense). Compared with 0 g/d (control group), digestible nitrogen, retention nitrogen (RN, g/d) and the efficiency of digestible nitrogen converted into retention nitrogen (RN/DN, %) of 300, 600 and 900 g/d groups were higher (p<0.05). The post-ruminal starch digestion of flaked corn were 71.36, 80.27 and 64.71 % when the amounts abomasally infused were 300, 600 and 900 g/d, respectively. When the amount of starch abomasally infused was more than 600 g/d, the post-ruminal digestion of starch decreased. 300, 600 and 900 g/d starch infusion groups showed higher metabolizable energy intake (ME) and net energy gains (NEg, MJ/d) than the control group, and the efficiencies of metabolizable energy converted into body weight (Kf, %) of these groups were higher than the control group by 38.31, 73.18 and 67.06% (p<0.05). Kf (Y, %) had a positive curved relation to starch of flaked com abomasally infused (X, g/d), $Y=36.1605X^{0.0760}$ (n=16, r=0.9308).

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.6
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• pp.823-829
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• 2016

Eight Holstein steers ($216{\pm}48kg$ body weight) fitted with ruminal and duodenal cannulas were used to evaluate effects of wheat straw processing (ground vs pelleted) at two straw inclusion rates (7% and 14%; dry matter basis) in dry rolled or steam-flaked corn-based finishing diets on characteristics of digestion. The experimental design was a split plot consisting of two simultaneous $4{\times}4$ Latin squares. Increasing straw level reduced ruminal (p<0.01) and total tract (p = 0.03) organic matter (OM) digestion. As expected, increasing wheat straw level from 7% to 14% decreased (p<0.05) ruminal and total tract digestion of OM. Digestion of neutral detergent fiber (NDF) and starch, per se, were not affected (p>0.10) by wheat straw level. Likewise, straw level did not influence ruminal acetate and propionate molar proportions or estimated methane production (p>0.10). Pelleting straw did not affect ($p{\geq}0.48$) ruminal digestion of OM, NDF, and starch, or microbial efficiency. Ruminal feed N digestion was greater (7.4%; p = 0.02) for ground than for pelleted wheat straw diets. Although ruminal starch digestion was not affected by straw processing, post-ruminal (p<0.01), and total-tract starch (p = 0.05) digestion were greater for ground than for pelleted wheat straw diets, resulting in a tendency for increased post-ruminal (p = 0.06) and total tract (p = 0.07) OM digestion. Pelleting wheat straw decreased (p<0.01) ruminal pH, although ruminal volatile fatty acids (VFA) concentration and estimated methane were not affected ($p{\geq}0.27$). Ruminal digestion of OM and starch, and post-ruminal and total tract digestion of OM, starch and N were greater (p<0.01) for steam-flaked than for dry rolled corn-based diets. Ruminal NDF digestion was greater (p = 0.02) for dry rolled than for steam-flaked corn, although total tract NDF digestion was unaffected (p = 0.94). Ruminal microbial efficiency and ruminal degradation of feed N were not affected (p>0.14) by corn processing. However, microbial N flow to the small intestine and ruminal N efficiency (non-ammonia N flow to the small intestine/N intake) were greater (p<0.01) for steam-flaked than for dry rolled corn-based diets. Ruminal pH and total VFA concentration were not affected ($p{\geq}0.16$) by corn processing method. Compared with dry rolled corn, steam-flaked corn-based diets resulted in decreased acetate:propionate molar ratio (p = 0.02). It is concluded that at 7% or 14% straw inclusion rate, changes in physical characteristics of wheat straw brought about by pelleting negatively impact OM digestion of both steam-flaked and dry-rolled corn-based finishing diets. This effect is due to decreased post-ruminal starch digestion. Replacement of ground straw with pelleted straw also may decrease ruminal pH.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.1018-1033
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• 2021

In this study, we aimed to assess the effect of flaking on the nutrient digestibility of corn grain in ruminants. In this regard, in vitro rumen fermentation, in situ rumen degradability, and in vivo metabolic experiments were performed. The automated gas production technique was used for the in vitro fermentation experiments. Six types of corn flakes with various degrees of gelatinization (32%, 41%, 48%, 66%, 86%, and 89%) were ground and incubated in rumen fluid to measure rumen fermentation characteristics and digestion rate. The in situ degradability of ground corn, whole corn, and corn flakes with 62% and 66% gelatinization was measured by incubation in the rumen of two cannulated Holstein cows. In vivo metabolic experiments were performed using 12 crossbred goats (29.8 ± 4.37 kg) using a 3 × 3 Latin square design. The dietary treatments consisted of ground corn and flaked corn with 48% or 62% gelatinization. In vitro experiments showed that as the degree of gelatinization increased, the digestion rate increased linearly, while the discrete lag time decreased linearly (p < 0.05). The effective rumen dry matter degradability, determined by in situ fermentation, was 37%p lower in corn flakes than ground corn, assuming a passage rate of 6%/h (p < 0.01), and there was no difference between the two flakes. In the in vivo experiment, there was no difference in dry matter intake, average daily gain, feed efficiency, and nitrogen utilization among the treatment groups (p > 0.05); however, the crude fat digestibility was lower for corn flakes than for ground corn (p < 0.05). To summarize, the rate of fermentation of corn flakes increased as the degree of gelatinization increased. However, non-ground corn flakes had lower rumen digestibility and did not improve in vivo apparent nutrient digestibility, compared with ground corn. In contrast to the assumption that flaked corn provides more energy to ruminant animals than ground corn, we conclude that the digestibility and energy value of corn flakes are lower than those of ground corn if mastication does not sufficiently reduce the particle size of corn flakes.