Efficiency of the use of index assessment methods in the dairy cattle breeding

The article reflects the comparative results of assessing the breeding value of dairy cattle by two methods: by a set of traits, according to the instructions in force in the Republic of Kazakhstan, and by the best linear unbiased prediction (BLUP) method, which is widely used in countries with the developed animal husbandry. The material for the research was the accounting data on the milk yield of black-and-white cows for 305 days of lactation, obtained from the database of the republican information and analytical system. The analysis of the data obtained on the average milk yield of black-and-white dairy cattle showed that their productivity is 1.8-2.0 times higher than the indicator of the breed standard approved in the current instruction, which determines the assessment of animals by the highest grading classes. In this connection, it was established that the selection of breeding stock in farms is carried out according to the productivity indicators, in this case the fundamental application of the instructions for grading dairy cattle is no longer valid. The use of the BLUP method for genetic assessment of the dairy cattle population showed that 17.0% of animals, whose breeding value was negative, were phenotypically higher than the average population indicator (4852 kg), and vice versa, some of the animals (20.3%), phenotypic indicators which were below the average, had a positive rating. Thus, it was found out that the possibility of error in the selection of livestock by phenotypic values may amount to 37.3% of the total controlled livestock.