Feed selection and radiocaesium intake by reindeer, sheep and goats grazing alpine summer habitats in Southern Norway

Radiocaesium concentrations (137Cs) were measured in extrusa from oesophageally fistulated sheep, goats and reindeer grazing alpine summer vegetation in Griningsdalen, Southern Norway in the period 1987–1989. The experiments with sheep and goats were conducted in different subalpine areas. The reindeer were, in addition, grazed in three areas in the low alpine zone. Grazing bouts lasted for 10–20 min and bite selections were recorded every 15 s through the grazing bout. Reindeer and goats had the most diverse food selection whereas sheep fed mainly on grasses, forbs and, to some extent, on leaves of willow. The reindeer extrusa had the highest radiocaesium activity, apparently to a large extent caused by intake of lichens in areas where this type of plants were present. Depending on the type of vegetation in the grazed areas the transfer of radiocaesium from soil to grazed vegetation (Bq kg−1 dry extrusa/Bq m−2 soil) was estimated to 0.02–0.04 in sheep, 0.02–0.05 in goats and 0.02–0.43 in reindeer for 1987.