In order to clarify the characteristics of the surviving plants and the productivities of their progenies, 1953 plants were collected from the old alfalfa fields in Hokkaido and Tohoku areas from 1969 to 1971. The collected old plants were transplanted in the observation nursery in Hokkaido National Agricultural Experiment Station (Located in Central-South Hokkaido) in a row with plants 0.75m apart and 0.75m apart between rows. The investigations were carried out in 1972 and 1973 for plant type, flower color, flowering time, spring vigor and fall vigor. The plants collected from the area Central-South-Hokkaido were open-pollinated and the seeds of the plants from the same collections were bulked. The progenies of the collections were tested for their yielding ability. According to this yielding performance, four strains were selected and about 2000 progenies were established in the spaced-planting nursery in 1973 and 27 plants were selected for the diseases resistance and seed yield in 1975. The yielding performance of the progenies of these 27 plants were tested from 1976 to 1978. The results were as follows: 1. The proportion of upright plants of East-Hokkaido population was the lowest. On the other hand, the proportion of upright plants of Tohoku population was the highest and it was about same as that of Du Puits. The proportions of upright plants of North-Hokkaido and Central-South-Hokkaido populations were relatively low and they were about same as that of Narragansett. Flower color related closely to plant type and the plants collected from the areas where the proportions of upright plants were high showed higher proprortions of purple flowered plants. On the contrary, the plants collected from the areas where the proportions of intermediate-prostrate plants were high showed lower proportions of purple flowered plants. Flowering time of the plants of Tohoku and Central-South-Hokkaido populations were early and those of the plants of North-Hokkaido and East-Hokkaido populations were late. Spring vigor of the plants of Tohoku population was the highest and it was as high as that of Du Puits. The plants of Central-South-Hokkaido population showed lower fall vigor than that of the plants of Tohoku population and it was intermediate between those of Du Puits and Narragansett. On the other hand, the plants of North-Hokkaido and East-Hokkaido populations showed lower fall vigor than that of Narragansett. Changes of the characteristics toward more prostrate type, lower proportions of purple flowered plants, later flowering time, and lower fall and spring vigors might be due to the elimination by winter injury. 2. Plant type showed significant correlations with flower color, flowering time, spring vigor and fall vigor. This indicated that collections of the plants with higher proportions of upright plants had higher proportions of purple flowered plants, earlier flowering time, higher spring vigor and higher fall vigor. 3. The progenies of the plants of Central-South-Hokkaido population showed 97.5 to 107.5 per cent of the three years' dry matter forage yield of Du Puits. The mean yield of the progenies was 102.1 per cent of Du Puits. The progenies of the selected plants from the population of Central-South-Hokkaido showed 86.0 to 117.7 per cent of the three years' dry matter forage yield of Du Puits. The mean yield of these progenies was 102.1 per cent of Du Puits. These progenies of the selected plants showed greater variation than those of non-selected plants, however, mean yields were the same. From the above results, the characteristics of the plants collected from Tohoku and Hokkaido were changed greately. Especially, plant type was greately changed from upright to prostrate in East-Hokkaido populations. This suggests that the recommendation of varieties to East-Hokkaido or North-Hokkaido should be made with the consideration of plant type. Particularly, in th

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The effects of the amount of nitrogen application, the ratio of split application, that is, the proportion of basic to top dressing and the time of top dressing were investigated in early-heading Italian ryegrass, Waseaoba, grown for seed. The seed yield was increased by raising the amount of nitrogen throughout the tested range from 0 to 12kg/10a. Split application of nitrogen produced a higher seed yield than the plot applied all nitrogen as basic fertilizer and the difference in the seed yield between 8kg N/10a (8N) and 12kg N/10a (12N) became smaller by splitting the nitrogen application. The seed yield was higher in the proportion of one basic to three top dressing (1-3) and two to two (2-2) in 4N and 2-2 in 8N and 12N than in the other proportions in the same amount of nitrogen, thus the seed yields of 2-2 and 1-3 in 4N and 2-2 in 8N became higher than that of the plot applied all nitrogen as basic fertilizer in 8N and 12N, respectively. This shows the marked improvement of nitrogen efficiency. An increase in the seed yield due to increased nitrogen application and split application of nitrogen was produced by the increase in number of ears and/or number of seeds per ear. From a comparison among times of top dressing in spring, nitrogen applied on April 13, the time of rapid stem elongation around 2 weeks after the beginning of stem elongation, was recognized to be the most beneficial for seed. Lodging at the beginning of flowering time tended to increase by raising the amount of nitrogenous fertilizer and by splitting the application of it. Judging from these experimental results, the following method of nitrogen application to Italian ryegrass grown for seed would be recommended. The amount of nitrogen application is recommended to be 8 to 12kg/10a, which should consist of a half as basic dressing and another half as top dressing at about 2 weeks after the beginning of stem elongation, when they are rapidly elongating. Taking into account of nitrogen efficiency and lodging, however, the amount of nitrogen application would be desirable to be less within the recommended amount.

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The investigation was carried out to evaluate the effects of soaking and wetting treatments on the dormancy breaking and enhancement of germination of green panic seed. The results obtained were as follows ; 1. Soaking both in running water and in water in a cup increased germination percentage in the test soon after soaking, and the seed soaked in running water germinated faster. 2. Soaking and drying treatment a month after harvest when the seed exhibited deep dormancy improved germination markedly in the tests a year or more after the treatment. In this experiment soaking treatment of 77 hours was more effective than the treatment of 3 or 24 hours. While the soaking and drying treatment 3 or 5 months after harvest when the seed exhibited shallow dormancy deteriorated germination in the tests 3 or more months after the treatment. 3. As the results of wetting treatment, enveloping ears in vinyl film for 3-7 days immediately after harvest, dormancy breaking of the seed slowed down for some time, but a year later germination percentage increased markedly and germination was nearly finished within 5 days after setting. 4. When soaking and drying treatment was done 3 months after harvest to the seed from ears enveloped in vinyl film for 7 days, germination was better than that of the seed without soaking and drying.

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Appropriate expression on the maturity is necessary for the right combination among varieties of silage corns. Current expressions like early and "very late" as well as the relative maturity scale in current use are not accurate enough for this purpose. I propose here "Hokkaido Relative Maturity" (HRM) Scale, which takes characteristics local dependence of corn growth rate on temperature. HRM is calculated by the equation: Σ(SHU)/HU=HRM (Days), where Σ(SHU) is simple sum of heat units accumulate between seeding and the best cutting stage for silage materials, that is untile the DM value reach 30% of the whole crop, and HU is an average of daily mean temperature above 0.1℃ over twelve locations. HU is equal to 17.5℃. The HRM values of "Wase-homare" and "Hokuyu" are 130 and 147 days, respectively.

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The influence of a series of temperature regimes on the dry weight production and the parameter of relative growth rate (RGR) was investigated in 8 tropical grasses, 6 temperate grasses and one arctic grass in the phytotron. Two objectives were involved, one to identify the tropical grasses which can achive a reasonable level of growth at low temperature and temperate grasses which can do likewise at high temperature, and the other to classify the growth pattern of grasses in relation to temperature. Four experiments were carried out in a phytotron at the following day/night temperatures ; 15/10, 21/16, 27/22, 30/25 and 36/31℃ for 20 days. Tropical grasses examined in the first experiment were Cenchrus ciliaris, Chloris gayana, Paspalum dilatatum and Setaria sphacelata and in the second experiment Digitaria argyrograpta, Panicum coloratum, P. maximum and Sorghum almum. In the third experiment Agropyron trichophorum, Bromus inermis, Festuca arundinacea, Phalaris arundinacea, Stipa hyalina (temperate grasses) were compared with Paspalum dilatatum as the control species, while in the fourth experiment Poa pratensis (temperate grass) and Trisetum spicatum (arctic grass) were compared with Paspalum dilatatum as the control. Results obtained were as follows: 1. The development of all the tropical grasses was very restricted at 15/10℃, but increased markedly at 21/16℃ and attained maximum value at 36/31℃. On the contrary, temperate and arctic grasses reached maximum development at temperatures ranging from 21/16 to 30/25℃ with a slight decrease both at 15/10 and 36/31℃. Stipa hyalina differed particularly from Poa pratensis and Trisetum spicatum in its ability to grow vigorously at high temperatures. 2. The growth parmeters of RGR were closely correlated with light intensity as well as with temperature. At 15/10℃ P. dilatatum and P. coloratum showed a higher RGR than Setaria sphacelata and P. maximum, while at high temperature the former two species had a lower RGR than the latter. However, Chloris gayana showed a high RGR both at low and high temperature. On the other hand, Stipa hyalina had the highest RGR among the temperate grasses at 36/31℃ suggesting a definite tolerance to high temperature. 3. Although most of the temperate grasses examined showed a higher RGR than the tropical grasses at low temperature, the reverse was observed at high temperature. Maximum values of RGR differed greatly in tropical and temperate grasses, varying between 0.25-0.35g/g/day for tropical grasses and with a value of about 0.15 for temperate grasses and the single arctic grass species. 4. Two basic patterns of temperature response, a warm and a cool type, were noted in the grasses subjected to the study. In the warm type, the highest RGR was achieved at 36/31℃ and the lowest at 15/10℃. In the cool type, intermediate values of RGR were recorded at temperatures between the low and high ranges while low values of RGR were noted at 15/10℃ and 36/31℃, respectively. Grass species belonging to Panicoideae and Eragrostoidea were of the warm response type and those belonging to Festucoidese of the cool response type.

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The influence of temperature on net assimilation rate (NAR) and leaf weight ratio (LWR) was investigated in 8 tropical grasses, 6 temperate grasses and one arctic grass. Details of the selected temperature regimes and of the species investigated were given in the previous paper of this series. 1. High light intensity increased the NAR in Paspalum dilatatum to a maximum value of 0.77g/g/day at the 36/31℃ temperature regime compared with 0.55g/g/day when light intensities were 0.558 and 0.340gcal/cm^2/day, respectively. The LWR response was in marked contrast to that of the NAR and was markedly higher at low light intensities. 2. The NAR of tropical grasses increased greatly with a rise of temperature from 15/10 to 27/22℃, while it was nearly constant at the level of 0.7g/g/day with higher temperature regimes. LWR of those grasses exhibited greater variation between species but tended to greater values at the highest and the lowest temperatures employed in the experiments. Setaria sphacelata and Cenchrus ciliaris had a high LWR and a markedly lower NAR at 15/10℃ compared to the other tropical grasses indicating that those grasses might be less tolerant of low temperature conditions. 3. The NAR of temperate grasses was nearly constant in a wide range of temperature, from 15/10 to 30/25℃, but decreased at 36/31℃. The NAR of Trisetum spicatum and Poa pratensis decreased above 27/22℃ and it was observed that these two grasses did not tolerate high temperature. The LWR increased at 36/31℃ more markedly in the temperate grasses in which the NAR decreased severely at this temperature. 4. It appears that the tropical grasses which can adapt to low temperature conditions are those having high NAR and low LWR under low temperature and that the temperate grasses which can adapt to high temperature conditions are those having high NAR and low LWR under high temperature. Paspalum dilatatum and Stipa hyalina show the greatest tolerance of low and high temperatures, respectively. 5. Values of NAR were closely correlated with RGR values and the importance of NAR for growth was confirmed. On the other hand, LWR values showed a strongly negative correlation with RGR values.

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The effects of eleven rates of fertilizer nitrogen (0-20kg/10a) on dry matter yields, nitrogen yields, nitrogen contents and nitrogen recovery rates of the plant tops were compared for five tropical grasses ; Eleusine corocana (African millet), Chloris gayana cv. Pioneer (Rhodes grass), Paspalum dilatatum cv. Nampuu (dallis grass), Panicum maximum cv. Gatton (Guinea grass) and Panicum maximum var. trichoglume cv. Petrie (green panic). Results: According to the patterns of their response to fertilizer nitrogen, grasses subjected to this experiment were divided into three groupes of grass as follows ; Groupe I African millet and Guinea grass, Groupe II Rhodes grass, and Groupe III dallis grass and green panic. Groupe I significantly increased dry matter yield even at lower rates of nitrogen application while groupe II gradually increased with increasing rates up to 20kg nitrogen per 10a. Groupe III has shown relatively lower increase in dry matter yield at lower rates of nitrogen application and drastical drop at higher rates of nitrogen application showing somewhat intermediate pattern between nitrogen responses of groupe I and II. Based on the above patterns of each group of tropical grass, the following methods of applicating nitrogen fertilizer will be suggested: Groupe I should avoid either light or heavy nitrogen application ; groupe II always requires heavy nitrogen application ; and groupe III should avoid excessively heavy nitrogen application.

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NADA, Y. (1980) Photoperiodic responses in flowering of main tropical pasture grasses. J. Japan. Grassl. Sci. 26, 157-164. Photoperiodic responses of 29 tropical grasses were investigated. Concerning with photoperiodic response, grasses were classified as follows: Shortday response Ear emerged earliest under 9hr daylength, followed by 12hr daylength and ear emergence was not observed under 15hr. Panicum bisulatum (nukakibi), Setaria viridis (enokorogusa), Pennisetum purpureum (napiergrass), Heteropogon contortus (speargrass), Dichanthium aristatum (Alabang X). Mediumday response Earliest under 12hr daylength, followed by 9hr and ear emergence was not observed under 15hr: Paspalum plicatulum, Hyparrhenia rufa (jaraguagrass). Ear emerged under any daylength although earliest under 12hr daylength: Axonopus compressus (carpetgrass), Paspalum dilatatum (dallisgrass), Panicum maximum (Guineagrass), Panicum virgatum (switchgrass), Cenchrus ciliaris (buffelgrass), Urochloa mosambicensis (sabigrass). Long-day response Ear emerged only under 15hr daylength: Digitaria decumbens (Pangolagrass), Paspalum notatum (bahiagrass), Pennisetum alopecuroides (chikarashiba). Ear emerged earliest under 15hr, followed by 12hr and ear emergence was not observed under 9hr daylength: Setaria sphacelata (setaria). Ear emerged under any daylength although earliest under 15hr daylength: Cynodon dactylon (bermudagrass). Others Ear emerged under 9hr and 12hr almost at same time and ear emergence was not observed under 15hr daylength: Brachiaria mutica (paragrass), Paspalum urvillei (vaseygrass). Ear emerged under 9hr and 12hr almost at same time followed by 15hr daylength: Digitaria adscendes (mehishiba), Paspalum thunbergii (suzumenohie), Bouteloua curtipendula (side-oats grama). Ear emerged under 12hr and 15hr almost at same time, followed by 9hr daylength: Paspalum distichum (Kishusuzumenohie). Special response to daylength was not observed: Chloris gayana (Rhodesgrass), Pennisetum clandestinum (Kikuyugrass), Themeda triandra (red-oat grass), Panicum coloratum (coloured Guineagrass), Melinis minutiflora (molassesgrass).

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Differences of growth of 29 main tropical pasture grasses under low (20/15℃ day and night) or high (30/25℃) temperature conditions were investigated. Kikuyugrass (Pennisetum clandestinum), dallisgrass (Paspalum dilatatum), setaria (Setaria sphacelata) and bermudagrass (Cynodon dactylon) showed good growth under low temperature condition and followed by Rhodesgrass (Chloris gayana), Guineagrass (Panicum maximum, Gatton), Paspalum plicatulum and Hyparrhenia hirta. Red-oat grass (Themeda triandra), speargrass (Heteropogon contortus), buffelgrass (Cenchrus ciliaris), jaraguagrass (Hyparrhenia rufa), coloured Guineagrass (Panicum coloratum), Kishusuzumenohie (Paspalum distichum), little bluestem (Andropogon scoparius) and side-oats grama (Bouteloua curtipendula) showed good growth under high temperature condition.

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A pot experiment to compare the acidity tolerance and symbiotic nitrogen fixing capacity among 11 varieties of alfalfa (Natsuwakaba, El unico, Williamsburg, Du Puits, Arizona common, Saranac, Common, Rhizoma, Caliverde 65, Aichi 10 and Moapa) was made with an acidic mineral soil (pH 5: unlimed soil) and the same soil adjusted to pH 7 with CaCO_3 (limed soil). Plant yield, nodulation, plant total nitrogen and nitrogen fixing capacity with acetylene reduction method were measured. The results obtained were as follows. 1. Plant yield of any variety grown at the unlimed soil was lower than that grown at the limed soil though there appeared slight differences among varieties. 2. In acidity tolerance of varieties grown at the unlimed soils on the basis of plant yield, Caliverde 65, Saranac and Moapa were relatively high whereas Common and Du Puits were low. 3. On the other hand, comparatively high acidity tolerance was shown in Rhizoma, Natsuwakaba and Saranac on the basis of relative plant yield of unlimed plots to that of limed plots while El unico and Arizona common were low. 4. Soil acidity had a more adverse effect on the nodule formation and symbiotic nitrogen fixation than on the root growth. 5. As the symbiotic nitrogen fixation system was damaged intensively under acidic soil conditions, it is recommended to apply nitrogen fertilizer moderately to grow alfalfa under those conditions.

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Studies were undertaken to investigate the effect of plant density on feeding value of sorghum. Three plant populations were constituted from 44.4, 11.1 and 3.7 plants/m^2 using commercial hybrid (Sudax). 1) The dry matter yield increased with increase of plant density, but tillers and dry matter of one plant decreased at flowering stage. 2) Plant proportions were varied with plant density and rind portion of stem increased with increase of plant density. 3) Cell wall constituents (CWC) and acid detergent lignin (ADL) contents of whole plants were increased with increase of plant density. 4) CWC hydrolysis was varied with plant portion. Pith of stem and leaf blade were the most hydrolytic portions. Rind of stem was the lowest hydrolytic portion. Variation in CWC hydrolysis and in vitro dry matter disappearance (IVDMD) of whole plant were observed among the different level of plant density. CWC hydrolysis and IVDMD were increased with decrease of plant density. Those differences of feeding values were depended on the variance of hydrolysis of pith of stem and leaf blade and their proportion rates. 5) Crop growth rate (CGR) increased with decrease of plant density at heading to flowering stage. At this period, digestible dry matter which dissolved by neutral detergent solution and cellulase increased with decrease of plant density. 6) Digestible dry matter production increased with increase of plant density and was influenced with its dry matter production. But there were almost no significant difference between high and middle plant density in flowering stage. Because the IVDMD of middle plant density was higher than that of high plant density.

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1. The experiment was conducted to know the effect of the methods of silage making and exposure of the silage making materials to rain during prewilting on the feeding value of grass silage. 2. The methods of silage making examined were the high moisture silage ensiled immediately after cutting with addition of formic acid and the low moisture silage ensiled the materials prewilted after cutting. The latter was divided into two of exposure and no exposure of the materials to rain during prewilting. The materials used were the first crop (cutting in April) and the aftermath (cutting in May) of Italian ryegrass (Lolium multiflorum, LAM). 3. Comparing the high moisture silage with the soilage, the digestibility of every composition fell, for example, the organic matter and crude protein digestibility fell 3-4% and 5-11%, respectively. Regarding the contents of the digestible nutritions, DCP and TDN fell 1.4-2.2% and 1-4%, respectively. 4. In comparison of the low moisture silage not exposed to rain during prewilting with the soilage, the digestibility fell such as 1-2% and 5-7%, respectively in the organic matter and the crude protein digestibility. Regarding the contents of the digestible nutritions, DCP fell 5-7%, but TDN merely 0-1%. 5. Comparing the low moisture silage exposed the materials to rain during prewilting with the soilage, the digestibility remarkably fell such as 6-9% and 11-13% in organic matter and crude protein digestibility, respectively. Regarding the contents of the digestible nutrition, DCP and TDN fell 1.5-2.7% and 6-10%, respectively. In this case, the feeding value largely fell mainly during prewilting on the field. 6. As stated above, the feeding value of the low moisture silage not exposed to rain during prewilting lowest remarkably fell comparing with that of the soilage materials among the silages tested here. And, in this case of the low moisture silage, a rain fall on the materials during prewilting caused a great decline of the feeding value. 7. Furthermore, the tendency of the changes of the feeding value estimated from chemical composition during silage making coincided mostly with the results of digestion trial by sheep The quality of the low moisture silage was more excellent than the high moisture silage.

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The fibrous residue obtained after extraction of leaf protein concentrate from ladino clover was ensiled with or without formaldehyde (0.85%/D.M.) and formic acid (2.8%D.M.) mixture and the effect of the additive treatment on the quality and the nutritive value of the silages were studied. For the purpose, wethers were fed the treated or untreated silages at 1.8-2.0% levels of dry matter per kg body weight as the sole ration. The results obtained were as follows ; 1. Silages of good quality were obtained from both the treated and untreated fibrous residues. The treatment lowered the pH value and the fermentation acids and ammonia formation. 2. Digestibilities of crude protein and crude fat were significantly lower in feeding of the treated silage than in feeding of the untreated silage. 3. Urinary nitrogen excretion was significantly depressed by the treatment. Consequently, the nitrogen retention significantly increased in feeding of the treated silage. 4. The concentrations of ammonia and VFAs in the rumen fluid were significantly lower in feeding of the treated silage than in feeding of the untreated silage. 5. The concentration of blood urea-nitrogen was significantly lowered with feeding of the treated silage, but plasma total protein level was significantly higher in treated silage feeding than in untreated silage feeding. 6. The concentrations of most of amino acids in the blood plasma were significantly increased with feeding of the treated silage, especially plasma lysine level was about 3.5 times higher in treated silage feeding than in untreated silage feeding. From the results mentioned above, it is concluded that the utilization of high moisture silage made from a fibrous residue of ladino clover was efficiently improved by addition of formaldehyde and formic acid before ensiling.

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The dispersion of heifer excreta in a flat and square pasture (1 ha) surrounded by fences with a watering place on an edge was examined, and the relationships between the excretal density of a site and its distance from the watering place were derived as decreasing exponential functions. Dispersion patterns of dung and urine in a pasture with the same shape as the above field were simulated by using the above mentioned relationships to clarify the formation process of excretal dispersion pattern. It was proved not only that grazing equipments, e.g., watering place, cause uneven excretal dispersion, but also that, when the spatially biased densities are formulated mathematically, the uneven dispersion of excreta can be expressed by the Poisson model.

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Orchardgrass sward was divided into four blocks, according to the amount of nitrogen fertilizer applied, each of which was sub-divided into four paddocks for rotational grazing. Each paddock was grazed five times for 7 days by 4 wethers. Nitrogen fertilizers (12, 24, 48 or 96kg/10a) were applied in a year, and its dressing was carried out at 7 days before the pasturing of sheep. The dressing amount of each time was one-fifth of yearly amount. As the amount of nitrogen fertilizer increased the nitrate-nitrogen content of herbage increased, and reached a peak of 0.88% in dry-matter basis in the third grazing of the N 96 treatment. Similarly the nitrogen content increased with increasing the amount of nitrogen fertilizer. The calcium and magnesium contents of the herbage were lower in N 12 treatment than in the other treatments. On the other side the phosphorus content decreased with increasing the amount of nitrogen fertilizer. Though the nitrate-nitrogen in the plasma and urea-nitrogen in the serum increased with the increase of nitrate-nitrogen and nitrogen content in herbage, no formation of methaemoglobin was observed. The experiment also did not show remarkable change in other blood constituents and detrimental effects on animal health or live weight gain.

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The flavor components of lucerne hay, Italian ryegrass and rice straw were isolated by trapping of headspace volatiles on Tenax-GC and by steam distillation and identified by a GC and a GC-MS to clarify the odors affecting the grass selection and intake of cattle. From these forage crops, a number of compounds, including 28 hydrocarbons, 20 alcohols, 2 esters, 7 aldehydes, 6 ketones, 1 lactone, 3 phenols, 12 acids, 5 sulfides and 5 halogen compounds, were obtained. The characteristic flavor components from three samples were as follows. 1) lucerne hay ; linalool, linalool oxide, geraniol, benzyl alcohol and methyl salicylate. 2) Italian ryegrass ; lauric, palmitic and stearic acids, hexanol, decanol, carbon disulfide, dimethyl sulfide and dimethyl disulfide. 3) rice straw ; the number of flavor compounds was smaller than the other two crops and all flavor compounds identified were also found in the lucerne hay and/or in the Italian ryegrass. It was indicated that the forage crop with high quality had a pleasant odor and was abundant in flavor components while the forage crop with poor quality was less odorous.

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Since the rejection of fecal odor by cattle causes the formation of dung patch in pastures, it is necessary to investigate the changes in the volatiles from feed in the digestive tracts and clarify the characteristic volatiles from feces. In this study three different diets: Italian ryegrass haylage, lucerne hay cube, and lucerne hay cube and formula feed were fed to two steers and the headspace volatiles from the feeds, rumen and duodenum juices, and feces were adsorbed on Tenax-GC and identified using a GC and a GC-MS. In the rumen some volatile compounds found in the feed decreased or disappeared while new volatiles appeared. The characteristic volatiles commonly found in the rumen were methyl ethyl ketone, phenol, p-cresol, indole and skatole. The profiles of voltiles of gastrointestinal juices were affected by the pH values. The VFAs (volatile fatty acids) could not be detected in the headspace volatiles of rumen juices at the original pH ranging 6.70 to 7.90, but after making the juice strongly acidic (pH 2.0), the VFAs could be detected. The production of volatiles in the digestive tracts were also influenced by the diets fed to the steers. The feeding of lucerne hay cube and formula feed, which has plenty of water soluble carbohydrates and protein, produced more volatiles in the digestive tracts than Italian ryegrass haylage and tended to increase the production of sulfur containing volatiles. Methyl ethyl ketone, phenol, p-cresol, indole and skatole were the characteristic volatiles from feces compared with the volatiles from feed and some portions of these compounds seemed to have been already produced in the rumen.

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[in Japanese]

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