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13476 pairs of mothers and daughters from 165 herds of red-white cattle used In 1963-1983, in Low Silesia and Opole region were studied. The values of all the traits analysed /milk and fat yield, fat content in milk/ were expressed as deviations of the means for the herd-year. Corrections were made for age and the season of calving. The evaluations were based upon the data referred to above; heritability, phenotyplc, genetic and environmental correlations were calculated in pairs of mothers and daughters. The values of heritability, phenotyplc correlations, particularly environmental correlations, were higher than those in the same breed estimated by similarities in half-sib groups. Incomplete elimination of parts of some common environmental influences for daughter and mothers could have caused that effect, in particular, the Influence of maternal environment.
Proportional correction factors for prediction 305-days milk and fat yields based on short-term cumulated yields dependend on production level, calving season and length of calving period for Black-White and Holstein-Friesian cows and crosses are estimated. Production level affected to all correction factors for days of calving, but calving period and season of calving affected to correction factors of initial and final months of lactation only.
Proportional, regression and modified regression correction factors for prediction of 305-days milk and fat yield of Black-White and Holstein-Friesian cows and crosses based on short-term cumulated yields were calculated. Cumulation from 1 to 10 and from 10 to 1 month of lactation was considered. There are different correction factors for cows of different breeds and crosses and for different traits.
For estimation correction factors 21417 milk and fat lactation yields and 13164 protein yields of Black-White and holstein-friesian cows and crosses are used. Estimated factors for correction milk, fat and protein yields are related to age of cow at calving, season of calving and both. There are different correction factors for age and season of calving for different breeds and crosses and for different traits.
Cows from the farms located in the Sudetes and highland of Sudets were included in the studies. Milk production and fertility of 21699 Red-White cows /14029 primigravida/ from 71 state farma and 1707 cows /558 primigravida/ kept on private farms were studied. The phenotype and breeding values of the cows were calculated according to: the number of cows in a stock, location of the farms above sea level, productivity level of stocks, agricultural quality of the farms. Breeding and phenotype values changed regularly and markedly, affected only by productivity level. The other factors did not affect significantly the average values of milk production in cows kept on both kinds of farms. Various environmental conditions in the Sudetes Region did not influence adversaly cow performance. Therefore, they cannot be an obstacle in the development of cattle breeding in this area.
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