Iodine

Iodine

Species: Cattle, sheep

Specimens: Serum, plasma or urine (sheep only).

Optimum number of animals to test for mob/herd/flock deficiency:  3-5 (serum, plasma) or 10 pooled urines (sheep only). 

General information about the test: 

Inorganic iodine is very stable compound.  Inorganic iodine measures the iodine intake of the animal over the previous 2-3 days and the effect of oral or parenteral treatment with iodine supplements.  It does not measure the reserves of iodine which are only in the thyroid gland.

Serum thyroxine is not a useful test to detect iodine deficiency in farm animals.

Reference Interval (serum, plasma, urine):

  • Cattle – Adequate > 40 umol/L
  • Sheep – Adequate > 40 umol/L (large goitres (60 grams) have been found in neonatal lambs produced  by ewes with serum iodine <10 umol/L)
  • Horse – Serum iodine measured in low numbers of normal horse suggest that their normal range may be much lower compared with other grazing animals  i.e. 10-30 umol/L, so serum thyroxine may perhaps be a more useful test in this species.
  • There are no reference ranges available for deer, alpaca or goats.