Influence of feeding types of cows on the content of heavy metals in milk

Around the industrial cities, the difficult environmental situation is due to the release of pollutants in the atmosphere that contain heavy metals, especially those that are dangerous to the environment, such as cadmium and lead. The increase in the accumulation of pollutant in soils of agricultural land also leads to the use of agrochemicals – pesticides and mineral fertilizers. Under such environmental conditions, it is necessary not only to grow crop production, but also to produce livestock products – milk. The production of environmentally safe, high-quality and competitive on the milk market requires the use of proven technological feeding and animal feeding methods. The selection of the optimal type of feeding of cows reduces the transition of heavy metals into dairy raw materials. In the experiment, it was found that the siln-root-type type of feeding had the smallest transition of Cd and Pb from feed rations into dairy raw materials, the transition factor of cadmium – 0.24, lead – 0.25. The most intense was the migration of Pb from the ration to milk from cows of the first control group with the silo-hinga-co-central type of feeding: the transition factor was 0.39 and Cd was 0.34. A similar situation was observed in cows of the first control groups with males and females feeding type, where the transition factor was 0.36 Cd and 0.34 Pb. The total supply of heavy metals with the diet for different types of feeding practically did not differ. The balancing of dietary rations with the specially developed mineral-vitamin premix “MP-A” contributed to the reduction of the transition of heavy metals Cd, Pb, Cu and Zn into milk, while the highest quality milk was obtained from cows with a haylage type of feeding. As a result of the experiment, it was possible to achieve a positive effect and reduce the content of heavy metals in milk of cows in all farms with different types of feeding animals for optimum quality and safety of milk, which met the requirements of the state standard, which convinces the transition factor, which was in the cows of the second experimental group on Cd 0,09 in animals with a sows-root-type type of feeding; 0.10 – silo-haylage; 0.12 – silage-hay type and 0.15 with silo-haylage-concentrate type, respectively; Pb – 0.01 in cows with a hill-and-hay type of feeding; 0.07 – silo-haylage-concentrate; 0.08 – silo-root crop and 0.09 with silo-hay type respectively; Cu – 0.01 in cows with silo-haylage and silo-root-crop type of feeding; 0.02 with silo-haylage-concentrate and silo-hay type respectively; Zn – 0.05 in animals with males and haylings type of feeding; 0.06 – silo-haylage-concentrate; 0.08 – silo-root crop and 0.010 with silo-hay type, respectively. In the third experimental group of cows, the average transition factor of heavy metals from milk to Cd, Pb, Cu and Zn was 0.04. The use of premix and bio-preparation has reduced the transition of heavy metals from milk to an average of 1.5–4.3 times. Productivity of animals was on average in cows of the second and third experimental groups of 17–22 kg per day compared with the control group – 14 kg. The content of Cd in the milk of dairy cows with a hay-concentrate-feeding type was 0.053 mg/kg in the first control group, in the second experimental group, where the mineral-vitamin premix “MP-A” was additionally fed to 0.024, and in the third, where Subcutaneous injection of biologically active drug “BP-9” was used up to 0.014 mg/kg; Pb from 1.794 mg/kg – to 0.331 and 0.032 mg/kg respectively; Cu from 2.63 mg/kg to 0.34 and 0.35 mg/kg respectively; Zn from 8.74 mg/kg to 4.97 and 3.87 mg/kg, respectively. Feeding cows to antioxidant premix allows approximately 2–2.5 times to reduce the transition from diet to dairy raw materials that are hazardous to animal health and the quality of milk toxicants for any type of feeding. Future studies are aimed at studying the effects of different types of feeding, taking into account the balancing of diets with a special premix for the production of high-quality, environmentally safe milk.