OPTIMIZATION OF MINERAL REQUIREMENTS FOR COWS OF THE BELARUSIAN HOLSTEIN DAIRY BREED IN II AND III LACTATION PERIODS

Abstract

Holstein cows are characterized by high milk yields and, in this regard, their need for organic and mineral components is higher than in animals of Belarusian Blackand-White breed. Mineral and vitamin supplements, or premixes, are introduced into their diets to make up for deficiencies of essential elements. The paper contains the results of zootechnical and economic assessment of the effect of moderately increased levels of minerals (from 10 to 50%) in the diets of Holstein cows of the Belarusian selection in the 2nd and 3rd third of lactation on productivity and milk quality, as well as on homeostasis, organic matter digestibility and nitrogen utilization in the animal body. The positive effect of moderately increased requirements for the above nutritional components in the animal diets with a predominance of bulky feed in relation to concentrates has been established.