Metabolic Behaviour of ¹³⁷Cs-^137mBa in the Lactating Goat

Summary

Investigations on the metabolism of ¹³⁷Cs in the lactating goat demonstrated that: (a) the biological half-time for removal of ¹³⁷Cs from the body was about 2–3 days, (b) at steady state, about 7 per cent of the daily dose of ingested ¹³⁷Cs was secreted daily in milk, about 40 per cent in the urine and about 40 per cent in the faeces, (c) the ¹³⁷Cs/K ratio in milk was 1·4 based on a dietary ¹³⁷Cs/K ratio of unity, (d) the mammary gland did not differentiate between ¹³⁷Cs and K, (e) the organ of highest concentration was kidney, with values 1·5 times that of muscle and other soft tissues, (f) the ^137mBa daughter metabolically dissociated from its ¹³⁷Cs parent in vivo so that the gamma activity of the whole blood of the living animal was 5·5 times that as usually determined. These and other findings are discussed and reference made to differences in ¹³⁷Cs metabolism between ruminants and non-ruminants.