Studies on the uptake, partition and retention of ionic and fallout radiocaesium by suckling and weaned lambs.

In the first part of this study 9 one week old lambs were fed, ad libitum, a liquid milk replacer diet containing 950 Bq 137Cs kg-1, for a period of 21 days. Absorption of the 137Cs from the milk replacer was over 90% during this period. The lambs were weaned onto a silage diet and then allocated to 2 groups (A and B). Group A was fed silage contaminated with fallout radiocaesium and group B with the same silage additionally contaminated with ionic 134CsCl. After a 3 week period the diets offered were changed over between the groups. During the silage feeding period the uptake of added ionic 134Cs was approximately twice that of fallout 134Cs present in the silage. These studies highlight the difficulties in using studies with the ionic form of the isotope to predict the animals' response to fallout contaminated feed.