Journal article

Estimation of genetic parameters for milk fat depression in dairy cattle

MPL Calus, MJ Carrick, RF Veerkamp, ME Goddard

Journal of Dairy Science | AMER DAIRY SCIENCE ASSOC | Published : 2005

Abstract

The objective of this study was to apply reaction norm models to milk recording data to investigate genetic variation in and environmental sensitivity of susceptibility to milk fat depression (MFD). Data comprised 556,276 test-day records of 80,493 heifers in 1043 herds. Breeding values and genetic variances for fat percentage and fat yield were estimated by applying random regression models to average herd-test-day fat percentage. Genetic and permanent environmental correlations between fat yield expressed in different environments ranged, respectively, from 0.83 to 1.00 and from 0.29 to 1.00. Genetic and permanent environmental correlations between fat percentage expressed in different env..

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University of Melbourne Researchers