К методике по определению селекционногенетических показателей персистентностилактации коров

The studies were conducted to examine the rate of persistency of lactation in relation to the features characterizing the milk production and reproductive qualities of Simmental breed cows. To search for the best way to assess persistency milk yield used seven measures of known formulas with different structure calculation of persistency. The analysis used data from 7214 control milking heifers 762, is the daughter of 24 bulls. Takes into account such factors as how a month milk yield, the peak milk yield, 100, 200 and 305 days of first lactation milk production, timing of peak lactation, nonreturn rate after insemination and calving interval. The studies of the heritability, genetic and phenotypic correlations. Found the heritability of test day milk yield was 0,094-0,283. The value of persistency milk yield a traits P SD200, P SD305 and P yv305 ratio was higher heritability (h 2 = 0,092-0,134), than for the duration of the nonreturn rate after insemination and calving interval but lower milk production traits. Falling value of daily milk yield after the peak of lactation depending of measures the persistency of profitability estimates the lactation curve by the indices P SD305 and P yv305. The calculated a coefficients of stability and permanence lactation by indices P 31, P To max200 and P To max305 had fewer value selection because of low genetic variability. The best combination of productive and reproductivettaits possessed animals, estimated by measures the persistency milk yield P SD200, P SD305 and P yv305.