Effect of iodine supplementation on milk iodine concentrations and
productivity of dairy cows
N.D. Grace, G.C. Waghorn, A.R. Mills and A.F. Death
AgResearch Grasslands, Private Bag 11008, Palmerston North, New
Zealand and Flock House Agricultural Centre, Privatge Bag 1900, Bulls,
New Zealand
Proceedings of the New Zealand Society of Animal Production, 1996,
56: 143-145
Iodine (I) concentrations in New Zealand pastures are low and may be
inadequate to meet the I requirements of lactating dairy cows. A trial was
undertaken with 400 cows to determine the effects of a single intra-muscular
injection of 2000 mg I (in popyseed oil) given at the beginning of lactation
on cow performance. The pasture I concentration ranged between 0.17-0.26
mg I/kg DM during of the trial and the supplement increased serum
thyroxine (T4) and milk I concentrations for 76 (P<0.05) and 170 (P<0.01)
days respectively. Iodine supplementation did not affect milk yield milk
composition or number of services per conception. To increase I status and
maintain milk I concentrations at or above 40 µg/l, that is at a concentration
twice that of untreated cows, 2000 mg I would need to be injected at 6
month intervals.
Keywords: NZSAPAB;
dairy cows; I supplementation; serum thyroid hormones; milk I; milk
yields; reproductive performance.
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Last Updated 18-03-1997
