Technetium metabolism by lactating goats.

The goat milk transfer coefficients of 99mTc, 95mTc and 99Tc, administered as pertechnetate (TcO4-), were 1.5 x 10(-4), 8.5 x 10(-4) and 1.1 x 10(-2) d L-1, respectively. The differences between the goat milk transfer coefficients of the three Tc isotopes administered as TcO4- were significant (p less than 0.05). The milk transfer coefficients of Tc were affected by chemical form and specific activity. Reduced 99mTc produced a transfer coefficient 17 times lower than that of 99TcO4- in the same goats. Reduction of pertechnetate in the rumen was evaluated to explain the low and variable transfer coefficients.