Dairy farming is one of the most effective livestock industries, providing valuable food for people. The adequate feeding decisive factor is its level, which is determined by the amount of energy, protein, essential amino acids, fats, carbohydrates and a wide range of biologically active substances to be entering the body with food in optimal proportions. The biologically active substances in highly productive cows diets often lack trace elements. Various premixes are used to enrich diet with trace elements. Therefore, the experimental study of the improved formulation of zonal premixes for highly productive Holstein cows using mixed ligand complexes of manganese, copper and zinc along with the study of their impact on productivity, metabolism, product quality and economic efficiency, has today an important scientific and economic value.

Trace elements enhance the enzyme activity of the gastrointestinal tract, improve digestion and utilization of nutrients by the body and biologically active substances and thus improves feed efficiency and animal performance. Despite the fact that the main source of trace elements for animals is feed, yet due to increased need of highly productive animals for these elements and insufficient quantities of certain trace elements in food, trace elements salt is being administered in diet. With normalization of trace elements one should be aware that each mineral element plays an important role in vital functions of animals and between them is a close relationship that should be considered when creating new mineral feed additives.

The purpose of research is to experimentally study the formulation of improved zonal premixes for highly productive Holstein cows using mixed ligand complexes of manganese, copper and zinc and to study their impact on the productivity and cost of feed per output unit. The research and economic experiment on the efficiency of using mixed ligand complex of manganese, copper and zinc for domestic production in Holstein cows feeding was carried out in the Dnipropetrovsk region. The cows for the experiment were selected on the 10–15-th day after calving by the principle of analogue age, date of last calving, body weight and milk production in the last lactation, daily milk yield and fat content. All selected cows were purebred counterparts with similar performance of their mothers and average fatness and were clinically healthy and kept under the same conditions.

During the scientific and economic experiment in the equalization period all cows were fed the same rations on the basis of calculated daily milk yield with 4 % fat. Because cows were on their 2–3 week after calving and they had to renew milking, for the daily requirement of energy supply with the actual milk yield every cow was additionally added with two feed units of 2 kg feed. The diet composed of vetch-oat hay, alfalfa hay, corn silage, molasses and fodder. The mineral feed included table salt and calcium dyphosphate.

The experimental cows diet in equalization period had the deficit amounting to 621.324 mg of Manganese, 101.76 mg of Copper, 1095.54 of Zinc, 15 mg of Cobalt and 18.84 mg of Iodine. To eliminate it the diets were added with sulfate salts of manganese, copper, zinc, cobalt and sodium iodide in grams per ton of fodder: 235.3; 35.9; 407.5; 6.04 and 1.86, respectively.

For the experiment there were selected 50 cows of Holstein breed with 2–3 lactations, which were divided into five groups with 10 heads in each. In the experiment period all cows were fed with equalization diets and were continuously milked at the fodder cost. Trace elements diets for the 1st control group cows continued their balancing by sulphate salts and sodium iodide, for the 2nd experimental group cows the manganese sulfate was substituted by manganese mixed ligand complex (243 g/t feed) for the 3rd experimental group cows copper sulfate was substituted by copper mixed ligand complex (50.8 g/t feed), for the 4th experimental group cows Zinc sulfate was substituted by zinc mixed ligand complex (379.9 g/t feed) and for the 5th experimental group manganese sulfate salts, copper and zinc was substituted by mixed legand complexes of manganese, copper and zinc (243; 50.8 and 379.9 g/t feed respectively). The use of above mentioned trace elements level was by 25 % lower as recommended.     

The average daily milk yield of experimental cows in equalization period was almost identical and fluctuated between 35.24–36.06 g milk with fat content of 3.61–3.63 %.

In the first month of lactation, the first half of equalization period, and the second pilot, experimental cows ate almost the same amount of feed, but at the beginning of the second experimental month the experiment cows were better to eat coarse and succulent fodder and they increased milk yield compared to control, so they increased the daily feed amount. In connection with the above specified for a deeper assessment of the impact of different forms and levels of manganese, copper and zinc in the body of Holstein cows we assessed their milk production for the last 70 days in the first 100 days of lactation.

Introduction to the diet of experimental group dairy cows of manganese, copper and zinc in doses of 47.6–48.2; and 50.0–51.1 7.4–7.8 mg / kg of dry matter, respectively, had a positive impact on the future of milk production. Over the past 70 days of continued milking period every control group cow gave 2856 kg of natural milk and cows from the 2–5 th experimental groups gave by 35–343 kg more. The difference in average daily yield was 0.5–4.9 kg. The experimental cows milk showed vivid increase in fat content by 0.08–0.33%. If we transfer the gross milk yield into 4 % fat milk, this indicator difference between the 2nd experimental group cows and the control will be 130 kg, or 3.38 %, with the 3rd – 250 kg, or 9.28 % (P <0.001), with the 4th – 363 kg or 13.47 % (P <0.001), and with the 5 th experimental group and the control is 572 kg, or 21.2 %
(P <0.001).

The milk of experimental group cows when compared with the control, although not too noticeable, but clearly increased its protein content (3.28–3.39 against 3.28 % in control).

Thus, according to the milk production of cows in the last 70 days period, one can see the positive effect of organic trace elements on animals. Organic forms of trace elements do not cause antagonistic action of one to the other.

The lower feed costs per 1 kg of 4 % fat milk were: 1 in the control group and 0.707 in the 2nd experimental 0.708 in 0.703 3rd, 4th and 5th 0.707 and 0.698 units energy.

The best indicators of milk production of cows and lower feed costs per unit of output were obtained in experimental cows through the use of organic origin trace elements, such as mixed ligand complex of Zn, Cu and Mn.

Key words: highly productive cows, diet, premix, trace elements, sulfates, mixed ligand complex of Zn, Cu and Mn, milk productivity, feed costs.