The main role of Zinc in animals is determined that it is a necessary component or activator of many enzymes and hormones. It strengthens the immune system. Shortage of Zinc reduces protein synthesis in the body.

Zinc deficiency in the diet inhibited growth, reduced fertility of animals. Prolonged deficiency can lead to infertility and reduction of its level in plasma, bone, pancreas, liver, kidney, decreases phosphatase activity in plasma, bone and duodenum, carbonic anhydrase blood carboxypeptidase A and B of the pancreas, heart lactate dehydrogenase, skeletal muscle, kidney, testis alcohol dehydrogenase.

In dairy cows by Zinc deficiency in diets reduced digestibility of nutrients, especially coarse and succulent fodder, because of decrease intensity of enzymatic processes in the proventriculus, which leads to reduction in the availability of feed energy efficiency of its use in animal products and the reproduction function.

Traditional sources of this metal are mineral salts in the form of sulfate and chloride compounds in which the gastrointestinal tract can be easily transformed into hydrooxysystem low bioavailability. Therefore, sufficient amount of trace elements inorganic salts  in the diet can lead to their deficit and pollution with heavy metals. At the same time crystallized water molecules contained in sulfates, can destroy compounds of trace elements and vitamins in premixes. In this regard, the best part of the feed additives introduce metalochelate complexes.

We made mixed ligands complex of Zinc, but before the application of this chelate in feeding farm animals it is necessary to explore it thoroughly and comprehensively.

The purpose our study was to determine the optimal dose of mixed ligands complex of Zinc, combined with Copper sulphate, Cobalt sulphate and sodium selenite feeding highly productive cows in the first 100 days of lactation and establish their impact on the balance of Zinc. For the experiment there were formed 5 groups of cows Ukrainian black and white dairy cattle. The animals in groups were selected on the basis of analogies by performance, age, live weight and origin.

In the preparatory and research periods of experiment the cows were fed with the same diet. Only difference was that in the research period for 70 days (from November 5 to January 13) control group cows were fed with premix composed of Zinc sulfate, Copper sulfate, Cobalt sulfate, sodium selenite, and cows of research groups – instead of sulfate Zinc fed mixed ligands complex of Zinc.

The experimental cows in group 2 received the same amount of pure Zinc as the 1st control group cows, and cows of the 3rd 4th and 5th research groups, respectively, 75; 50 and 25 % of Zinc 2nd research group.

Obtained during the experiment results showed some effect of different levels of Zinc in the diet on its metabolism in the body of research groups cows.

The content of Zinc in the feces of cows of research groups were lower than control 130.59–849.02 mg or 13.5–87.5 %, and urine – 1.91–4.46 mg, or 7.8 –18.1 %.

Milk obtained from cows 2, 3, 4th and 5th research groups containing Zinc, respectively, by 9.45; 32.84; 41.71 and 25.51 mg and 5.1; 17.4; 22.1 and 13.5 % more, over control milk.

Experimental animals dominated of control cows by Zinc deposits in the body by 122.3–243.1 mg or 25.5–50.6 %. The postponement of Zinc in the body of research groups of cows as a percentage of the consumed amount exceeded control by 6.5–26.8 %.

Increased Zinc balance and greater excretion it with milk led indicators improve assimilation of this element in cows research groups by 19.7–42.6 %.

So, as a result of the research obtained data showing a positive effect of feeding dairy cows during the first 100 days of lactation Zinc in the form of mixed ligands complex the absorption of said trace elements. However, among the studied doses highest rate of assimilation of trace elements noted for doses of 2.5 kg / ton of feed.

Key words: highly productive cows, premix, minerals, chelates, copper sulfate salts of trace elements, Zinc, Cobalt, organic-mineral complex, Selenium.