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Purpose: study of the effect of mineral nutrition on digestibility and the use of nutrients of rations. Materials and methods. Repair heifers served for research from 6- to 18-months of age. According to the methods of groups of analogues, two groups of heifers, black and motley breed were formed. The control group received a feeding diet adopted in the economy. Animals of the experimental group were fed by the ration with the optimal level of mineral substances. Contents binding. Feeding, watering is individual. The determination of nutrients of the rations was carried out according to the techniques adopted. Results. It has been established that the age of animals, as well as the balance of rations on the complex of the missing mineral elements, has a noticeable effect on the digestibility of nutrients. In repairing heifers with an optimal mineral feeding level, an increase in dry and organic matter, raw protein, raw fat, raw fiber, without nitrous extractive substances is marked. Increased digestibility coefficient of nutrients of the diet, namely dry and organic matter by 1,38% and 1,78%, crude protein 2,82% and 3,40%, raw fat, 3,21% and 2,65%, raw fiber 3,55% and 2,56%, without nitrous extractive substances – 0,7% and 1,33%. These physiological studies show that with age in animals, the use of nitrogen changes. So in 6-month-old heifers of the experimental group, the degree of nitrogen's absorption from the adopted with feed is 30,01%, from the digestible 44,9%. 18-month-old - respectively, from the age taken with the feed – 18,96%, from the digestive – 30,05%. This is due to the relative increase in the fiber diet and slowing the growth intensity of muscle tissue. The use of nitrogen varies also under the influence of the level of mineral substances in rations. Studies have shown that the replenishment of their deficiency in the rations of animals of the experimental group ensures an increase in nitrogen deposits in a body by 10,9-11,6%. The degree of its use (both from the feed and digested) was higher. |
