The effect of higher iodine supply in cows in the Czech Republic on the iodine content in milk

摘要

The aim of the present study was to obtain an overall knowledge of cow milk iodine levels before processing by food industry followed - up by updating the substantion for evaluation of optimal intake by the human population. Iodine concentration in fresh cow milk from 187 farms covering 67 districts of the Czech Republic was assessed by the Sandell - Kolthoff Method. Average iodine concentration in a group of 187 bulk samples from distinct localities of the Czech Republic was 323,7 μg I.l~(-1) and significant variations of iodine content in milk from different farms expressed by variation range < 10 to 2512 μg I.l~(-1) was detected. The variations reflected marked differences in iodine saturation of dairy cows. Average milk iodine concentration is twice and a half the findings detected before supplementation which was initiated between the years 1997 - 1999, and is higher than the current European standard. Deep iodine deficiency in fodder, non - corrected by feed supplements, was found in 4,3% of milk samples with the values < 20 μg I.l~(-1). Iodine milk concentrations above 500 μg I.l~(-1) were detected in 18,7% farms. It is recommendable to regulate the offer of supplements containing iodine according tothe physiological requirements of the animals, their production and environmental conditions.