The quality of fiber and the effectiveness of use in rations of Holstein-Kholmogor cows

Abstract

Abstract. The purpose of the research is to determine the optimal level of fibre and its fractions, neutral detergent fibre (NDF) and acid detergent fibre (ADF), in the ration of cows with milk yield 6–7 thousand kg according to the period of the physiological cycle. The scientific and economic experiment was carried out with two groups of cows, control and test, 10 animals in each other, during the whole period of lactation. The ration of control group cows corresponded to the economic one. The analysis of the crude fibre in feeds doesn't identify a reasonably accurate content of the fibre and its fractions. Therefore, the research includes the elaborated method of fractionation of structural carbohydrates (Van Soest et al.). As a result of the research, the optimal level of the crude fibre and its fractions (NDF and ADF) was determined in the cow rations according to the periods of the physiological cycle. It was established that the level of the crude fibre should be 20.5 %; NDF – 40.0 %; ADF – 25.0 % during the first phase of lactation (14–100 days). For the period of the second phase of lactation (101–200 days) the content of the crude fiber – 22,5 %, NDF – 41,3 %, and ADF – 26,3 %. For the period of the third phase of lactation (201–305 days) the level of the crude fibre should be 25,0 %; NDF – 45,5 %; ADF – 25,4 %. The novelty of the research is that we determined the requirements of the milk cows for the crude fibre, NDF and ADF according to the physiological periods in the conditions of the Arctic region. Separation of the fibre into fractions makes it possible to reveal more fully its composition, and consequently to show more precisely digesting of each fraction in the gastrointestinal tract of ruminants and to determine the role of fibre in providing of animals by energy.