Productivity and biological value of milk of cows of various eco-genetic types

Abstract

Abstract The article gives comparative characteristics of the quality indicators of dairy raw materials obtained from Holstein first-calf heifers delivered to the Volgograd region of Russia from different countries. The research study consisted in processing the data of qualitative and quantitative indices of the cow’s milk production and assessing the nutritional and biological parameters of milk according to current standards. Differences on productivity, in the nutritional and biological values of milk depending on the ecological and genetic types of animals have been revealed. In terms of the milk yield for 305 days of lactation, the research has established the superiority of animals of American selection compared with ones of German, Danish and Australian selection by 100 kg, 600 kg and 620 kg, respectively. The cows of German selection were registered to have the highest content of the weight fraction of milk fat, i.e., 4.01%. Australian Holstein heifers had the highest weight fraction of milk protein (3.24%) and amino acids (valine, isoleucine, leucine, lysine, methionine, tryptophan, phenylalanine, aspartic acid, cystine, arginine and histidine). Animals of Danish Holstein breed were noted for a higher content of macro- and microelements, i.e., calcium, magnesium, zinc, manganese, iodine and silicon. For animals of Danish and American selections, some activities to increase the weight fraction of milk protein have been recommended to perform.