• Title/Summary/Keyword: Rice feed

Search Result 656, Processing Time 0.023 seconds

Physicochemical Properties of Rice-based Expanded Snacks according to Extrusion Conditions (Extrusion 제조 조건에 따른 쌀 스낵 제품의 이화학적 품질특성)

  • Eun, Jong-Bang;Hsieh, Fu-Hung;Choi, Ok-Ja
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.43 no.9
    • /
    • pp.1407-1414
    • /
    • 2014
  • Physicochemical properties of rice-based expanded snacks extruded with rice flour, high amylose starch, and isolated soy protein were investigated using a twin-screw extruder. The ingredients were extruded at various feed moisture contents (19~23%) and screw speeds (200~400 rpm) at a constant feed rate (43.4 kg/hr). Bulk density and apparent density of rice snacks were 0.06~0.21, and 0.55~0.65 respectively. Bulk density, apparent density, water absorption index, and breaking strength of rice snacks increased with increasing feed moisture content and decreasing screw speed. However, expansion and water solubility index of rice snacks increased with decreasing feed moisture content and increasing screw speed. Hunter's color L values of rice snacks was lower with increasing screw speed at feed moisture contents of 19% and 21%, but was not significantly different from a feed moisture content of 23%. On the other hand, a and b values of rice snacks were higher with increasing screw speed a feed moisture content of 19%. X-ray diffraction intensity of rice snacks decreased with decreasing feed moisture content and increasing screw speed. X-ray diffraction of rice snacks was V-type at feed moisture contents of 19% and 21% and screw speeds of 300, and 400 rpm. In the microstructure of the cross section of rice snacks, air cells in rice snacks were not well formed, and cell walls were thicker with increasing feed moisture content and decreasing screw speed.

Milling Characteristics of Vertical Small Scale Milling Machine for the Rough Rice -Optimum design conditions of main spindle speed, ceramic coating length of roller and feed screw pitch- (수직형 소형정미기의 벼 도정 특성 -주축회전수, 롤러의 세라믹코팅길이, 이송스크루 피치의 최적 설계조건에 대하여-)

  • 연광석;한충수;조성찬
    • Journal of Biosystems Engineering
    • /
    • v.26 no.2
    • /
    • pp.177-188
    • /
    • 2001
  • This research was carried out to examine the optimum design conditions of a vertical small-scale milling machine where the rough rice is processed directly into the white rice in one pass. Effects of the main spindle speed, feed screw pitch and ceramic coating length of the roller on various milling characteristics such as white rice processing capacity, electric energy consumption, rice temperature increase, broken rice ratio, moisture reduction, outlet force and crack ratio increase were studied. The results are as follows. 1. The maximum white rice processing capacity and the lowest crack ratio increase, were obtained from a machine with specification: main spindle speed of 970rpm having a feed screw pitch of 19㎜. 2. The minimum electric energy consumption was obtained with the main spindle speeds of 900 and 970rpm respectively having a feed screw pitch of 19㎜. 3. The rice temperature was increased as the feed screw pitch decreased and the main spindle speed increased. 4. Broken rice ratio was relatively low with the range of 0.8∼1.3%. 5. Moisture content loss was with the range of 0.05∼0.4%. 6. The highest outlet force was 0.72kg$\_$f/ with 900rpm of the main spindle speed and 19㎜ of the feed screw pitch and the lowest outlet force was 0.18∼0.34kg$\_$f/ with 970rpm of the main spindle speed and 16㎜ of the feed screw pitch. 7. The optimum design conditions for the vertical small-scale milling machine were obtained at 970rpm of the main spindle speed, 19㎜ of the feed screw pitch and 20㎜ of the ceramics coating length.

  • PDF

Effects of Replacing Corn with Brown Rice or Brown Rice with Enzyme on Growth Performance and Nutrient Digestibility in Growing Pigs

  • Zhang, Defu;Li, Defa;Piao, X.S.;Han, In K.;Yang, Chul J.;Shin, In S.;Dai, J.G.;Li, J.B.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.15 no.9
    • /
    • pp.1334-1340
    • /
    • 2002
  • A 4 week experiment was designed to study the effects of replacing corn with Chinese brown rice or adding different amylase in brown rice basal diet on growth performance and apparent fecal digestibilities of nutrients in growing pigs. One hundred and eight cross-bred pigs (Duroc${\times}$Landrace${\times}$Large White), weighing an average of $18.35{\pm}0.12kg$, were randomly assigned to 6 treatments with 6 replications per treatment. Diet in treatment 1 was corn-soybean meal basal diet, and in treatment 2, 3 and 4, corn was replaced by brown rice on rates of 33.3%, 66.7% and 100% respectively on the basis of treatment 1. And diets in treatment 5 and 6 were similar to treatment 4 except two kinds of amylases, glucoamylase and ${\alpha}$-amylase, were added respectively. The brown rice used in this experiment was husked from one kind of early, long grain, non-glutinous rice (ELGNR, indica rice) in southern China. The results indicated that there was a slight improvement in growth performance of pigs in brown rice treatments (p>0.05). The blood urea nitrogen value in treatment 2 was lower than that in treatment 1 (p<0.05). The differences of apparent fecal digestibilities of most nutrients were significant (p<0.05) except CP. Digestibilities of GE, OM and DM in treatment 4 were the best and digestibility of crude fat in treatment 5 appeared best (p<0.05). Contrast results between treatment 1 and treatment 2 to 4 indicated that the digestibility of GE, OM and DM increased significantly with the replacing rates of brown rice (p<0.05). Contrast results between treatment 4 and 5 indicated that adding glucoamylase in brown rice diet increased growth performance slightly (p>0.05) but not for digestibilities. This experiment shows a positive effect of brown rice on growth performance, especially on nutrient digestibility.

NUTRITIVE VALUES AND GROWTH RESPONSE OF CATTLE FED AMMONIA TREATED RICE STRAW

  • Maeng, W.J.;Chung, T.Y.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.2 no.1
    • /
    • pp.1-6
    • /
    • 1989
  • Nutritive values and fermentation rates of rice straw treated with 3% anhydrous and 3% aqueous ammonia were evaluated both in vitro and sheep metabolism trials. Daily gain, feed efficiency and feed cost per gain were also determined with growing Holstein bulls fed anhydrous and aqueous ammonia treated rice straw. Crude protein was increased 2.4 fold and NDF was decreased 6.5%, but ADF and cellulose were not different between untreated and ammonia treated rice straw. An average of 35.5% of total added ammonia-N retained in the rice straw and other 64.5% was not retained in the rice straw. Ammonia treatment increased in vitro DM, NDF, ADF and cellulose digestibilities by 44.8%, 43.3%, 49.4% and 42.4%, respectively, and fermentation rates by 63.3%, 132.4%, 49.4% and 42.4%, respectively. In sheep metabolism trials, DM digestibilities of rice straw treated with anhydrous and aqueous ammonia were increased 22% and 36%, respectively, and digestible DM intakes by 48% and 70%, respectively in sheep fed anhydrous and aqueous ammonia treated rice straw over untreated rice straw. Rumen ammonia and blood urea were considerably higher in sheep fed ammonia treated rice straw than sheep fed untreated rice straw. Daily gain of Holstein bulls was increased 20.8% and 29.9% and rice straw intakes were increased 28.4% and 44.3% in anhydrous and aqueous ammonia treated rice straw over untreated rice straw. Feed conversion was improved 9.5% and 10.3% and feed cost/gain was reduced 7.1% and 9.2% respectively in anhydrous and aqueous ammonia treated rice straw group as compared with untreated rice straw group.

Studies on the Wild Yeasts in Korea(IV) (한국산 야생효모에 관한 연구 4)

  • 박명삼
    • Korean Journal of Microbiology
    • /
    • v.11 no.4
    • /
    • pp.157-166
    • /
    • 1973
  • Fermented feed using rice, barley, wheat, and defatted rice brans as the raw materials were prepared by 3 species of wild yeasts which were selected among 35 strains of yeasts isolated, and their analytical values were examined. The results were as follows : 1. The three yeasts were identified as H.amomala var. anomala (No.225), Candida utilis (No.400), and Irpex-cellulase(consors) (no.403-A). 2. The optimum pH, and sugar concentration of these yeasts in liquid culture were pH 5.0 and Bllg. 10.deg. each. The optimum temperature was 30.deg.C for No.225 and No.403-A, 25.deg.C for No.400. The No.225 and No.403-A grow at higher temperature than 37.deg.C and 40.deg.C each. 3. The No.225 yeast had a large vegetative cell and strong sugar fermentability. The No.225 and 403-A could assimilate cellobiose, xylose, $KNO_2$ and $KNO_3$. These properties were fit for bran fermentation. 4. The No.403-A microorganism was a yeast-like microbe and showed cellulase activity which might help the propagation of other yeasts on the brans. 5. The analytical data of fermented feed indicated the following order of usable value ; rice-wheat-barley bran 4:4:2, rice-wheat bran 5:5, rice-barley bran 5:5, rice-defatted rice bran 5:5. 6. the fermented feed were prepared by mixing brans, 0.3% ammonium sulfate and 5%(w/w) inoculum of yeast suspension in 4% glucose solution. Water content 70-80%, fermentation temperature 25-30.deg.C, and fermentation time 2-3 days were given. 7. The rice-wheat bran 5:5 and rice-barley bran 5:5 fermented feed showed 11, 17-11.45% protein increase, and the rice-barley-wheat bran 4:4:2 and rice-defatted bran 5:5 showed 3.75-6.03% protein increase. 8. The fermented feed prepared in this experiment by the author might work as a nutritive feed using microbial cell body, enzymes produced by microbes and other microbial cell constituents.

  • PDF

Mechanical and Operational Factors Affecting the Efficiency of Rice Polishing Machines (정미기의 능률에 미치는 기계적 요인및 작동조건에 관한 연구)

  • No, Sang-Ha
    • Journal of Biosystems Engineering
    • /
    • v.1 no.1
    • /
    • pp.15-15
    • /
    • 1976
  • In analyzing the operational characteristics of a rice whitening machine, the internal radial pressure of the machine was measured using strain gage equipment. Changes in cylinder and feed screw configurations, screen type, cylinder speed and counter-pressure levels were examined to determine their impact on the quality and quantity of milled rice and the performance of the machine. The results are summarized as follows: 1. The internal radial pressure in the whitening chamber varied with the surface condition of the grain being processed. During the first or second pass through the machine, pressure was relatively low, reached a maximum after two to three passes with combinations I and II, three to six with combination III and then began to fall. 2. The pitch of the feed screw and the size of the feed gate opening which determine the rate of entry of grain into the whitening chamber, appeared to be the most important factor aff-::cting the degree of radial pressure, quality and quantity of milled rice and the efficiency of the machine. Using a feed screw with a wide pitch (4.8cm), radial pressure was relatively high and head rice recovery ratio \vere quite low. In this case capacity and machine effic?iency were much higher than obtained when using a feed screw with a narrow pitch (2.3cm). Very significant responses in radial pressure, head rice recovery rates and machine capacity were observed with changes in cylinder speed and counter-pressure levels when using the wide pitch feed screw. 3. The characteristics of the screen which surrounds the whitening chamber had an important effect on whitening efficiency. The existence of small protuberances on the original screen resulted in significant increases in both machine capacity and efficiency but without a significant decrease in head rice recovery or development of excessive radial pressure. Further work is required to determine the effects of screen surface conditions and the shape of the cylinderical steel roller on the rate of bran removal, machine efficiency and recovery rates. The size of the slotted perforations 0:1 the screen affects total milled rice recovery. The opening size on the original screen was fabricated to accommodate the round shape of Japonica rice varieties but was not suitable for the more slender Indica type. Milling Indica varieties with this screen resulted in a reduction in total milled rice recovery. 4. An increase in cylinder speed from 380 to 820 rpm produced a positive effect on head rice recovery for all machine combinations at every level of counter-pressure used in the tests. Head rice recovery was considerably lower at 380rpm using a wide screw pitch when compared to the results obtained at speeds from 600 to 820 r.p.m. The effects of cylinder speed On radial pressure, capacity and machine efficiency showed contrasting results, depending on the width of the feed screw pitch. With a narrow feed screw pitch (2.3cm), a direct proportional relationship was observed bet?ween cylinder speed and both radial pressure and machine efficiency. In contrast, using a 4.8 centimeter pitch feed roller produced a series of inverse relationships between the above variables. Based on the results of this study it is recommended when milling Indica type long grain rice varieties that the cylinder speed of the original machine be increased from 500-600 rmp up to a minimum of 800 rpm to obtain a greater abrasive effect between the grain and the screen. The pitch of the feed screw should be also reduced to decr?ease the level of internal radial pressure and to obtain higher machine efficiency and increased quality of milled rice with increased cylinder speeds. Further study on the interaction between cylinder speed and feed screw pitch is recommended. 5. An increase in the counter pressure level produced a negative effect On the head rice recovery with an increase in radial pressure, capacity, and machine efficiency over all combinations and at every level of cylinder speed. 6. Head rice recovery rates were conditioned primarily by the pressure inside the whitening chamber. According to the empirical cha racteristics curve developed in this study, the relationships of head rice recovery ($Y_h$) and machine capacity ($Y_c$/TEX>) to internal radial pressure ($X_p$) followed an inverse quadratic function and a linear function respectively: $$Y_h^\Delta=\frac{1}{{1.4383-0.2951X_p^\ast+0.1425X_p^{\ast\ast}}^2} , (R^2=0.98)$$$$Y_c^\Delta=-305.83+374.37X_p^{\ast\ast}, (R^2=0.88)$$The correlation between capacity and power consumption per unit of brown rice expressed in the following exponential function: $$Y_c^\Delta=1.63Y_c^{-0.7786^\{\ast\ast}, (R^2=0.94)$$These relationships indicate that when radial pressure increases above a certain range (1. 6 to 2.0 kg/$cm^2$ based On the results of the experiment) head ricerecovery decrea?ses in a quadratic relation with a inear increase in capacity but without any decrease in power consump tion per unit of brown rice. On the other hand, if radial pressure is below the range shown above, power consumption increases dramatically with a lin?ear decrease in capacity but without significant increases in head rice recovery. During the operation of a given whitening machine, the optimum radial pressure range or the correct capacity range should be selected by controlling the feed rate and/or counter-pressure keeping in mind the condition of the grain, particulary the hardness. It was observed that the total number of passes is related to radial pessure level, feed rate and counter-pressure level. The higher theradial pressure the fewer num?ber of pass required but with decreased head rice recovery. In particular, when using high feed rates, the total number of passes should be increased to more than three by reducing the counter-pressure level to avoid decreaseases in head rice recovery (less than 65 percent head rice recovery on the basis of brown rice) at every cylinder speed. 7. A rapid rise in grain temperature seemed to have a close relationship with the pressure generated inside the whitening chamber and, subsequently with head rice reco?very rates. The higher the rate of increase, the lower were the resulting head rice recoveries.

Mechanical and Operational Factors Affecting the Efficiency of Rice Polishing Machines (정미기의 능률에 미치는 기계적 요인및 작동조건에 관한 연구)

  • 노상하;최재갑
    • Journal of Biosystems Engineering
    • /
    • v.1 no.1
    • /
    • pp.17-48
    • /
    • 1976
  • In analyzing the operational characteristics of a rice whitening machine, the internal radial pressure of the machine was measured using strain gage equipment. Changes in cylinder and feed screw configurations, screen type, cylinder speed and counter-pressure levels were examined to determine their impact on the quality and quantity of milled rice and the performance of the machine. The results are summarized as follows: 1. The internal radial pressure in the whitening chamber varied with the surface condition of the grain being processed. During the first or second pass through the machine, pressure was relatively low, reached a maximum after two to three passes with combinations I and II, three to six with combination III and then began to fall. 2. The pitch of the feed screw and the size of the feed gate opening which determine the rate of entry of grain into the whitening chamber, appeared to be the most important factor aff-::cting the degree of radial pressure, quality and quantity of milled rice and the efficiency of the machine. Using a feed screw with a wide pitch (4.8cm), radial pressure was relatively high and head rice recovery ratio \vere quite low. In this case capacity and machine effic\ulcorneriency were much higher than obtained when using a feed screw with a narrow pitch (2.3cm). Very significant responses in radial pressure, head rice recovery rates and machine capacity were observed with changes in cylinder speed and counter-pressure levels when using the wide pitch feed screw. 3. The characteristics of the screen which surrounds the whitening chamber had an important effect on whitening efficiency. The existence of small protuberances on the original screen resulted in significant increases in both machine capacity and efficiency but without a significant decrease in head rice recovery or development of excessive radial pressure. Further work is required to determine the effects of screen surface conditions and the shape of the cylinderical steel roller on the rate of bran removal, machine efficiency and recovery rates. The size of the slotted perforations 0:1 the screen affects total milled rice recovery. The opening size on the original screen was fabricated to accommodate the round shape of Japonica rice varieties but was not suitable for the more slender Indica type. Milling Indica varieties with this screen resulted in a reduction in total milled rice recovery. 4. An increase in cylinder speed from 380 to 820 rpm produced a positive effect on head rice recovery for all machine combinations at every level of counter-pressure used in the tests. Head rice recovery was considerably lower at 380rpm using a wide screw pitch when compared to the results obtained at speeds from 600 to 820 r.p.m. The effects of cylinder speed On radial pressure, capacity and machine efficiency showed contrasting results, depending on the width of the feed screw pitch. With a narrow feed screw pitch (2.3cm), a direct proportional relationship was observed bet\ulcornerween cylinder speed and both radial pressure and machine efficiency. In contrast, using a 4.8 centimeter pitch feed roller produced a series of inverse relationships between the above variables. Based on the results of this study it is recommended when milling Indica type long grain rice varieties that the cylinder speed of the original machine be increased from 500-600 rmp up to a minimum of 800 rpm to obtain a greater abrasive effect between the grain and the screen. The pitch of the feed screw should be also reduced to decr\ulcornerease the level of internal radial pressure and to obtain higher machine efficiency and increased quality of milled rice with increased cylinder speeds. Further study on the interaction between cylinder speed and feed screw pitch is recommended. 5. An increase in the counter pressure level produced a negative effect On the head rice recovery with an increase in radial pressure, capacity, and machine efficiency over all combinations and at every level of cylinder speed. 6. Head rice recovery rates were conditioned primarily by the pressure inside the whitening chamber. According to the empirical cha racteristics curve developed in this study, the relationships of head rice recovery ($Y_h$) and machine capacity ($Y_c$/TEX>) to internal radial pressure ($X_p$) followed an inverse quadratic function and a linear function respectively: $$Y_h^\Delta=\frac{1}{{1.4383-0.2951X_p^\ast+0.1425X_p^{\ast\ast}}^2} , (R^2=0.98)$$ $$Y_c^\Delta=-305.83+374.37X_p^{\ast\ast}, (R^2=0.88)$$ The correlation between capacity and power consumption per unit of brown rice expressed in the following exponential function: $$Y_c^\Delta=1.63Y_c^{-0.7786^\{\ast\ast}, (R^2=0.94)$$ These relationships indicate that when radial pressure increases above a certain range (1. 6 to 2.0 kg/$cm^2$ based On the results of the experiment) head ricerecovery decrea\ulcornerses in a quadratic relation with a inear increase in capacity but without any decrease in power consump tion per unit of brown rice. On the other hand, if radial pressure is below the range shown above, power consumption increases dramatically with a lin\ulcornerear decrease in capacity but without significant increases in head rice recovery. During the operation of a given whitening machine, the optimum radial pressure range or the correct capacity range should be selected by controlling the feed rate and/or counter-pressure keeping in mind the condition of the grain, particulary the hardness. It was observed that the total number of passes is related to radial pessure level, feed rate and counter-pressure level. The higher theradial pressure the fewer num\ulcornerber of pass required but with decreased head rice recovery. In particular, when using high feed rates, the total number of passes should be increased to more than three by reducing the counter-pressure level to avoid decreaseases in head rice recovery (less than 65 percent head rice recovery on the basis of brown rice) at every cylinder speed. 7. A rapid rise in grain temperature seemed to have a close relationship with the pressure generated inside the whitening chamber and, subsequently with head rice reco\ulcornervery rates. The higher the rate of increase, the lower were the resulting head rice recoveries.

  • PDF

Rice as an alternative feed ingredient in swine diets

  • Kim, Sheena;Cho, Jin Ho;Kim, Hyeun Bum;Song, Minho
    • Journal of Animal Science and Technology
    • /
    • v.63 no.3
    • /
    • pp.465-474
    • /
    • 2021
  • It has become important to explore alternative feed ingredients to reduce feed costs, which are burdensome for livestock production. In addition, it is desirable to find efficient and functional alternative ingredients for traditional feed ingredients in pig diets, considering the stress and sensitivity of disease of pig. Rice is produced around the world like corn that is the typical energy source in pig diets. Although the nutritional quality varies depending on the degree of milling, rice, except whole grains (paddy rice), contains more starch than corn and its structure and granule size are easier to digest than corn. In addition, the fact that rice has fewer non-starch polysaccharides (NSP) and anti-nutritional factors (ANFs) is also effective in improving digestibility and various polyphenols in rice can help modulation of immune responses, which can be beneficial to the gastrointestinal environment and health of pig. Many studies have been conducted on rice focusing on things such as degree of milling, substitution rates of corn, granule size, and processing methods. Most results have shown that rice can be partially or completely used to replace corn in pig diets without negatively affecting pig growth and production. While further research should focus on the precise biological mechanisms at play, it was confirmed that the use of rice could reduce the use of antibiotics and pig removal and protect pigs from gastrointestinal diseases including diarrhea. From this point of view, rice can be evaluated as a valuable feed ingredient for swine diets.

Evaluation of Chinese Brown Rice as an Alternative Energy Source in Pig Diets

  • Piao, X.S.;Li, Defa;Han, In K.;Chen, Y.;Lee, J.H.;Wang, D.Y.;Li, J.B.;Zhang, D.F.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.15 no.1
    • /
    • pp.89-93
    • /
    • 2002
  • A total of six crossbred barrows ($Duroc{\times}Landrace{\times}Large$ White, $44.17{\pm}1.94kg$ BW) were housed conducted to evaluate apparent fecal digestibilities of Brown Rice (BR) as an alternative energy source in growing pigs. Pigs were housed individually on metabolism crate on the basis of body weight. Four treatments contained: 1) 100% of corn-soybean meal (C100; Control diet), 2) 75% of corn-soybean meal diet plus 25% of corn meal (C25), 3) 100% of brown rice-soybean meal diet (BR100), 4) 75% of brown rice-soybean meal diet plus 25% of brown rice meal (BR25). Brown rice has an excellent gross energy and crude protein composition compared to corn. The BR used had 3,801 kcal of gross energy/kg, 8.0% crude protein, 2.6% of ether extract, 0.035% calcium and 0.35% total phosphorus. The best digestibilities of energy (87.75%), DM (81.71%) and CP (78.57%) were observed in BR 100 group and the worst were found in Corn 25 group. The nutrient digestibility was not significantly different in most nutrients. Through this experiment, BR appeared a good alternative energy source that can replace corn yellow to 100% in growing pigs. Therefore, the price relationship between corn and BR may provide an excellent opportunity for pork producers to use BR in order to reduce feed costs provided that diet has been balanced for digestible amino acids.

Feed Value of Whole-Crop Silage Rice by Cultivars and Plant Parts at Different Transplanting and Harvest Dates

  • Lee, Jihyun;Ku, Bon-Il;Shim, Kang-Bo;Shin, Myeong-Na;Jeon, Weon-Tai
    • Journal of The Korean Society of Grassland and Forage Science
    • /
    • v.40 no.3
    • /
    • pp.138-148
    • /
    • 2020
  • This study was carried out to find out the changes in the growth characteristics and feed value of the three different whole-crop silage rice cultivars of whole-crop silage rice such as Jonong, Yeongwoo and Mogwoo to develop an efficient double cropping system. This study showed that there were significant differences biomass and feed values among cultivars but no clear difference among transplanting dates. Dry weight and height were in order of Mogwoo, Yeongwoo, Jonong (p<0.05). Dry weight and feed value of Jonong showed no significant difference after 21 days after heading (DAH), it was expected to be harvested before DAH 30 days. Yeongwoo showed a lower dry weight than Mogwoo, but heading date was earlier than Mogwoo, so one can expect a higher feed value than Mogwoo. Mogwoo had lower crude protein and total digestible nutrient than the other two cultivars but relative feed value in stem was higher than that of the other cultivars, but had higher dry weight than other cultivars so it was considered to take an advantage as a silage rice. Therefore, the results of this study suggest that the selection of whole-crop silage rice on the cropping system be made comprehensively by considering the heading characteristics of the cultivars and the feed value.