I$sup 131$ IN MILK AND THYROID OF DAIRY CATTLE FOLLOWING A SINGLE CONTAMINATION EVENT AND PROLONGED DAILY ADMINISTRATION
A sing1e I/sup 132/ contamination event of forage was simulated by administering I/sup 131/--labeled feed to dairy cattle twice daily for 31 days, all feed samples being spiked on day one with 5 mu C I/sup 131/ per sample. Peak milk concentration in the dairy cattle occurred on the fourth day with about 0.4% of the first day's dose of 10 mu C observed per 1 of milk. The peak thyroid concentration in the cattle occurred after 1 week and was about 70% of the first day' s dose of I/sup 131/. In a second study, 5 mu C of I/sup 132/ were fed daily to three cows starting before parturition and continuing for a period of 6 months of lactation. Apparent equilibrium of I/sup 131/ in the thyroid was reached after 2 weeks and approached twice the daily feeding level. A suggestion of increased thyroid uptake occurred following parturition. The I/ sup 131/ concentration in the colostrum was 2-3 times that in the milk on the seventh day of lactation, after which time a gradual increase was observed. The per cent of the daily dose of I/sup 131/ appearing in the milk varied from 0.4 to 1.0% over a 6month period. Following an increase in the daily stable iodine content of the cow's diet from 5 mg to 2 g per day, milk concentration of I/sup 131/ decreased 50% and thyroid concentrations decreased more than 90%. (auth)
- Research Organization:
- General Electric Co., Richland, Wash.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-18-008086
- OSTI ID:
- 4133168
- Report Number(s):
- HW-SA-3074; 0017-9078
- Journal Information:
- Health Physics (England), Vol. Vol: 9; Other Information: HW-SA-3074. Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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