Influence of copper, cobalt and iodine microelements on the exchange of 137Cs in the cows organisms at different physiological states

Abstract

Aim. To estimate the impact of additions of different doses of copper, cobalt and iodine salts to the diet of dry and lactating cows on the absorption and removal of 137 Сs from the organism. Methods. Four groups of black and white breed cows –– were selected for the study on the farm in Narodychi district of Zhytomyr region following the traditional methods. The animals were fed salts of microelements with concentrated feedstuffs. Specifi c radioactivity of feedstuffs, feces, urine, milk was defi ned by the gamma-spectrometry method using AMA-OZF analyzer. Results. During the dry period the content of 137 Сs in nutrition of cows of experimental groups was almost the same, whereas its removal from the organism of animals was different depending on the impact of microelements on the degree of radionuclide absorption. The exceeding of the norms of copper and cobalt by 30 % and iodine – by 70 % promotes the decrease of “visible” absorption of cesium and enhances its removal due to the radionuclide, accumulated in the tissues. The radioactivity of the diet of animals dur- ing lactation increased considerably (22–26-fold) and amounted to 17–22 kBq per day; at the same time high bioavailability of the radionuclide was revealed. The increase in 137 Cs content in the diet of cows during the grazing period is related to the use of contaminated fi elds. In May specifi c radioactivity of cow milk was the lowest; its insignifi cant increase (50–65 Bq/l) was observed in June, July and August. The radioactivity of cow milk in September and October increased considerably (150–184 Bq/l). The fortifi cation of the diet of animals of the 3 rd experimental group with copper, cobalt, and iodine promoted the decrease in the radioactivity of cow milk comparing the cow milk of the 1 st experimental group and the milk of the 4 th experimental group. During the lactation period the least absorption of the radionuclide was revealed for the normative consumption of all the microelements, and the highest – for the increased consumption of cobalt only. Conclusions. The vegeta- tive feedstuffs of dairy cattle in Polissia provides the requirement of cobalt for 30–35 %, iodine – for 25–30 %, copper – for 70 % in winter, and during the grazing period in summer – for 25, 35, and 60 % respectively. The fortifi cation of the diet of cows with microelements promotes the decrease in the absorption of 137 Сs in the gastrointestinal tract and its reduced transfer into cow milk.