The estimation of genetic parameters of test day dry matter intake, energy intake and milk yield of Holstein cows

dc.contributor.advisorSchaeffer, L.R.
dc.contributor.authorLiu, Xuelu
dc.date.accessioned2021-01-26T15:14:16Z
dc.date.available2021-01-26T15:14:16Z
dc.date.copyright1998
dc.degree.departmentDeparment of Animal and Poultry Scienceen_US
dc.degree.grantorUniversity of Guelphen_US
dc.degree.nameMaster of Scienceen_US
dc.description.abstractThis thesis is an investigation of the genetic parameters of dry matter intake, energy intake and milk yield by using random regression models and Gibbs sampling procedure. Estimates were obtained using 19,065 test-day (TD) records on 3,313 cows during the first lactation. Heritabilities of 0.22, 0.22 and 0.28 were estimated for the average TD dry matter intake, energy intake and milk yield, respectively. Lowest genetic variances were found in early lactation for dry matter and energy intakes. Both residual and permanent environmental variances varied greatly at different stages of lactation for dry matter intake, energy intake and milk yield through the lactation. Selection for milk yield would not cause high correlated genetic gains in dry matter and energy intakes due to moderate genetic correlations. Positive correlations of EBV between dry matter intake and type traits suggested that selection on conformation could increase dry matter intake.en_US
dc.identifier.urihttps://hdl.handle.net/10214/24003
dc.language.isoen
dc.publisherUniversity of Guelphen_US
dc.rights.licenseAll items in the Atrium are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectgenetic parametersen_US
dc.subjectdry matter intakeen_US
dc.subjectenergy intakeen_US
dc.subjectmilk yielden_US
dc.subjectrandom regression modelen_US
dc.subjectGibbs sampling procedureen_US
dc.titleThe estimation of genetic parameters of test day dry matter intake, energy intake and milk yield of Holstein cowsen_US
dc.typeThesisen_US

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