Study of the content of essential mineral elements in the feed of dairy cows against the background of increased concentrations of toxic metals Cd and Pb in plants

Uncontrolled entry of pollutants – heavy metals into the environment creates obstacles to the production of environmentally safe, biologically complete cow's milk. The accumulation of pollutants in the soil reduces the supply of essential mineral elements to plants, which are necessary to ensure the full feeding of animals. In such environmental situations, it is important to analyse feed rations for the content of essential and non-essential mineral elements. Samples of feed included in the main diet were taken on four experimental farms specialising in the production of cow's milk, the agroecosystems of which were located around the industrial centre and near environmentally unfavourable objects – roads, enterprises for the extraction (processing) of gas condensate, etc. The samples were analysed for the content of mineral elements by atomic adsorption spectrophotometry. Statistical data processing – STATISTICA software suite version 10.0. The feed was found to exceed the permissible level for cadmium by an average of 2.1-3.2 times, lead – 2.4-5.7 times, copper – 1.4-2.3 times, zinc – 1.2-2.4 times. In cereal and legume hay, the concentration of cadmium and lead exceeded permissible levels by 3.2 and 5.7 times, respectively. Against this background, there is a deficiency of calcium in various types of diets of cows from 1.4% to 47.5%, phosphorus – from 1.5% to 62.3%, magnesium – from 2.7% to 64.4%, potassium – from 0.8% to 37.9%, sulphur – from 2.3% to 48.8%, among trace elements, iron – from 2.3% to 48.8%, cobalt – from 5.0% to 80.0%, iodine – from 4.0% to 60.7%. The reason for the deficiency of vital mineral elements in plants (feed) is different, including changes in soil pH, but mainly antagonism between mobile forms of toxic elements and essential elements. For the production of high-quality milk, it is necessary to normalise toxic metals in the diets of cows with different types of feeding and eliminate the lack of minerals with the help of specially developed feed additives (mineral and vitamin premixes), which will prevent elementosis in cows, which is a pressing issue in many countries of the world. Future studies will be aimed at monitoring the concentration of mineral elements in animal feed kept in the forest-steppe and steppe zone and Donetska oblast of Ukraine