Digestibility of substances, balance of Nitrogen, Zinc and Manganese in highly productive cows of the Holstein breed of German selection in the first period of lactation for feeding mixed ligand complexes of Zinc, Manganese and Co-balt

Abstract

The article deals with the results of research to study the digestibility of nutrients in the ration and metabolism of Nitrogen, Zinc and Manganese in high-yielding Holstein cows of German selection in the first period of lactation for feeding mixed ligand complexes of Zinc, Manganese and Cobalt. The research was performed in the conditions of Terezyne Ltd., Bila Tserkva district, Kyiv region. There was an increase in the coefficients of digestibility of dry matter in cows of the 2nd-5th experimental groups compared with animals of the 1st control group, respectively by 1.8–3.5 % (P < 0.05); organic matter by 0.3–2.5 %; crude protein by 0.5–4.2 % (P < 0.05 – P < 0.01); crude fat by 1.1–1.8 %; crude fiber by 1.3–3.3 % and nitrogen-free extractives by 2.1–4.2 %. Cows of the experimental groups consumed more Nitrogen than the cows of the control group: 20.18 g or 2.4 % – the 2nd group, 55.06 g or 6.6 % – the 3rd, 42.52 g or 5, 1 % – 4th and 28.98 g or 3.5 % – 5th experimental group due to better eating of the feed mixture. General consumption level of Nitrogen in relation to excreted with milk and deposited in the body of cows of the control group was 32.02 %, and in animals of the 2nd, 3rd, 4th and 5th experimental groups – 33.59 %; 37.31; 36.99 and 34.97 %. In relation to the total digested amount, the proportion of Nitrogen deposited in the body and excreted with milk in animals of the control group was 42.38 %, and in the experimental – 44.25–47.34 %. Doses of Zinc, which provided its existing rate of 54–85 % due to the mixed ligand complex, positively influenced on the the metabolism of trace elements in the organism of experimental cows. Assimilation of Zinc in the organism was determined by the amount of its secretions with milk and deposits in the body and in absolute terms it was the lowest in cows of the 4th and 5th experimental groups – 562.7 mg and 671.6 mg against 740.8 mg in the 1st control group and the largest – 784.7 mg and 801.3 mg in animals of the 2nd and 3rd experimental groups. The use of a mixed ligand complex of manganese ensured its positive balance in the organism of cows and the absorption of the trace element in the organism of experimental cows ranged from 22.5 % in the 2nd experimental group to 33.2 % in the 3rd experimental group. The best indicators for the metabolism of Nitrogen, Zinc and Manganese were got in the third experimental group whose cows were fed a feed mixture, that in 1 kg of DM contained, mg: Zinc – 54.7; Manganese – 54.7; Cobalt – 0.7; Selenium – 0.3; Copper – 12 and Iodine – 1.1.