1968 Volume 14 Issue 1 Pages 56-75
Japan, a predominantly mountainous and hilly country with proximity to the sea, needs precise study in topographycal and local climatic differences especially for its high-altitude grassland planning, with this as the objective, field studies and observations have been carried out for 3 years from 1963 on for acquiring scientific data on the reaction of grazing dairy cattle in such high altitude inclement environments, to set techniques for improvement of herd management and grassland development. Results obtained in this study can be summarized as follow : 1. Location of the three farms studied were Kiyosato (Yamanashi Pref. 1300-1400m-improved sown pasture, Jersey herd), Kirigamine (Nagano Pref. 1600-1800m-native grass_pasture, Holstein herd) and Tobira (Nagano Pref. 1600m-sasa pasture for winter grazing only, Jersey herd). All of them locate in the mountainous regions of central part of Honshu. Animals of Shinshu Univ. Farm (770m) and of Tokyo Univ. Farm (<50m) were also used as control in this study. Hachibuse pasture (Nagano Pref. 1800-19COm-native grass pasture) grazed in summer season by the animals of Tobira, was also studied. 2. As environmental factors ; characters of the climate, soil and vegetation, especially the seasonal fluctuation of the pasture herbage quality were investigated. a) Climatic conditions are characterized as features of rather cool summer (max. temp. rarely exceeds 25℃), long and severe cold winter (min. temp. often reaches lower than -15℃) with fairly high precipitation (1400-1600mm.) and year-round high humidity (>65%) except short spell of dry in August, frequent dense-fog in sumrner, and low atmospheric pressure (820-890mb.) throughout the year. b) Soils are of similar character, viz. very acidic (pH 4.0-4.5), phosphor-fixing, light soils of volcanic ash origin, in all pastures. c) Nutritive value of the pasture herbages seemed rather high ; in Kiyosato, sown pastures (50ha) were wisely managed since 10 years ago, and pasture herbages showed high crude protein content (22-26%) throughout the grazing season and high O.M. digestibility (78-79%). In Kirigamine, its native grass pasture (69ha) was used for grazing of young Holstein and Jersey stock of small number and its herbage quality showed fairly high crude protein content (10-12%), except that of late autumn (4-5%). In Tobira (13ha), sasa leaves were grazed by 13 Jersey stock under snow-covered condition in severe winter time, its crude protein content was±10%. Under such environmental conditions, the foliowing benefits were found in these 3 pastures ; firstly, rather cool summer favoured even growth of introduced pasture plant during the season than in lowland, and sasa leaves are very precious forage of fairly good quality for wintering especially as provider of ample amount of carotene. 3. Both native grasses in Kirigamine and sasa in Tobira showed rather low level of essential minor elements (Co : 0.16ppm. Cu : 4.1〜7.6ppm. Zn : 18.1〜30.8ppm), but herbages of sown pasture grown on the adjacent similar soil showed much higher level of such minor elements (Co : 0.33〜0.39ppm, Cu 11.0〜14.0ppm, Zn 47.8〜68.8ppm). 4. Through grazing behaviour observations both as herd and as individual, it was found that a) diurnal patterns of grazing and ruminating forms of dairy herd were quite rhythmical, b) grazing behaviour patterns of the herd were sensitively influenced by sudden meteorological changes such as rain- or snow-fall, c) in the system of grazing during day-light hours, as in case of Kirigamine and Tobira (also Hachibuse), grazing time was not so long as in case of Kiyosato, and rt/gt value (presented by HANCOCK) were always high, which means animals were not allowed to graze longer time to ingest needed forages. This understandings were supported by the results obtanined in grazing intake investigation simultaneously executed. d) in the system of day and night grazing, in the case of
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