Absorption, distribution and milk secretion of radionuclides by the dairy cow. II. Radiorubidium
Mullen, A.L.; Stanley, R.E.; Moghissi, A.A.
Health Physics 24(4): 417-427
1973
ISSN/ISBN: 0017-9078 PMID: 4698184 Document Number: 62471
4 lactating Holstein-Friesian cows received a single oral dose of 1.9 mCi 86RbCl, and all milk, faeces and urine from the cows were collected for the next 4 days. 18 h after ingestion of the radionuclide, a max. concn. of 0.16% of the dose/l. appeared in milk. The activity was eliminated by the cows via milk in 2 stages with biological half-lives of 13 and 84 h. After 66 h, 50% of the 86Rb had been excreted, 8% being via the milk. After a total of 180 h, approx. 75% of the administered activity had been eliminated. In a 2nd study, one lactating cow was given an intravenous injection of 1.9 mCi 86RbCl and 3 calves were dosed orally with 0.56, 0.52 or 0.89 mCi; the tissue distribution of the radionuclide after various lengths of time is described. The biological half-life for the transfer of intravenously-administered 86Rb into milk was 41.9 plus or minus 4.5 h, with a peak concn. of 0.14% of the dose/l. at 24 h after administration. The cow was killed at 113 h at which time approx. 56% of the administered dose had been excreted, of which 11% was via the milk.