Milk iodine as influenced by an iodophor teat dip

We quantitated the increase of iodine in milk from iodophor teat dips and determined the mode by which that iodine entered the milk. In one trial with teat dipping for 1 wk, iodine in milk increased 8.8 microgram/100 ml. In another trial, only right udder halves were dipped with the iodophor. Samples of milk from the left udder half increased in iodine corresponding to the right udder half only slightly less. Tincture of iodine was applied to the skin between the vulva and the point of udder attachment of cows. Samples of milk from the group with tincture increased markedly in iodine content over the control group. Iodophor teat dips increased the iodine in milk by 8 to 10 microgram/100 ml. The primary mode of increased iodine appears to be absorption through the skin and entry into the milk by the milk synthesis process rather than by contamination from the teat's surface.