In a trading notice, citing European Commission Regulation (EU) 2015/861, it said the maximum content of iodine (I) in complete feed for dairy cows is 5mg/kg.
The spokesperson said the Irish Department of Agriculture issues trader notices to advise its clients on matters of best practice, legislation clarification, and procedural changes.
However, the Department added that particular legislation recommended that the maximum level of iodine in complete feed for dairy cows should be 2mg/kg.
“Milk containing high levels of iodine is unsuitable for use in certain high value-added markets important to the Irish dairy industry, such as infant formula,” noted the Department.
Clarification sought
A spokesperson for the Department of Agriculture told us the need for clarification arose following a publication on the subject from Ireland’s farming research agency, Teagasc, in January this year. That agency warned about excessive supplementation of iodine in dairy feed concentrates, with it reporting that current levels in compound dairy feed were higher than cows’ requirements and the existing Teagasc recommended levels.
Teagasc says: Iodine (I) is an essential trace mineral for all animals.
Grazed grass is the most profitable feed available for dairy cows in Ireland, but most of the grass grown provides inadequate iodine to meet lactating cow requirements. As a result, iodine supplementation is necessary.
Teagasc research
This month, Teagasc recommended that cows receive 12mg supplemental iodine per day, unless a deficiency is diagnosed on the farm.
Its recent research on commercial dairy farms found that, on average, a pasture-only diet provided 0.25mg iodine per kg dry matter (DM). For a cow eating 17kg DM, this means an intake of 4.25mg iodine per day on grass only, it said.
Additional quantities should be offered so that the cow receives the recommended 12mg of supplemental iodine per day, recommended the Teagasc note.
“This means if 2kg concentrate is offered to cows, it should be formulated to the 12mg/day I feeding rate, and the inclusion rate should be 6mg/kg.
“Offering additional iodine to cows will result in higher milk iodine. If higher feeding rates or alternative sources of I are used on farm, the inclusion rate in the concentrates fed should be reduced accordingly so that 12mg per cow per day supplemental I is not exceeded.”