JOHN GILL
Does teat spraying with an iodine based product increase serum iodine in dairy cattle?
Fortunately this question was asked and answered by veterinarian Martha Camps of Vetora, Te Awamutu recently.
Martha selected a dairy farm that did not currently supplement with or use any iodine based products. Six cows were selected at random, marked and their serum iodine measured. The concentrations in the sera ranged from 27 – 40µg/L with a mean of 32µg/L.
Three marked cows were teat sprayed with a 1.4 dilution of an iodine based teat spray twice daily for the next seven days, while the other cows in the herd were teat sprayed with a chlorhexidine based product.
On day seven, the same six cows were again blood tested. The serum iodine results for the three untreated control cows were almost the same as prior to spraying, with a narrow range of 30 – 32 µg/L. However the serum iodine in the three treated cows had doubled to a mean of 68ug/L, with a range of 60 – 84µg/L.
This small trial shows that the iodine in teat spray passes through the skin and significantly elevates serum iodine levels.