Covariance Functions Across Herd Production Levels for Test Day Records on Milk, Fat, and Protein Yields
نویسندگان
چکیده
منابع مشابه
Estimation of Genetic Parameters for Milk Production Trait in Holstein Cows of the Mazandaran Gavdasht Herd Using Test Day Records
Random regression models (RRM) are used for genetic estimations of milk traits in dairy cows. RRM utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. In this study, to estimate genetic parameters for milk production trait, test day records (TDR) were collected from the first lactation of Holstein co...
متن کاملWithin-herd effects of age at test day and lactation stage on test-day yields.
Variance ratios were estimated for random within-herd effects of age at test day and lactation stage, on test-day yield and somatic cell score to determine whether including these effects would improve the accuracy of estimation. Test-day data starting with 1990 calvings for the entire US Jersey population and Holsteins from California, Pennsylvania, Wisconsin, and Texas were analyzed. Test-day...
متن کاملestimation of genetic parameters for milk production trait in holstein cows of the mazandaran gavdasht herd using test day records
random regression models (rrm) are used for genetic estimations of milk traits in dairy cows. rrm utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. in this study, to estimate genetic parameters for milk production trait, test day records (tdr) were collected from the first lactation of holstein co...
متن کاملGenetic parameters for first lactation milk yields at three levels of herd production.
A multivariate linear model was used to estimate sire variance and covariance components and residual variance components for first lactation milk yield and logarithms of yield at three herd production levels using Restricted Maximum Likelihood with the Expectation-Maximization algorithm. Data for four separate analyses were 305-d, mature equivalent first lactation milk records from cows sired ...
متن کاملPrediction of daily milk, fat, and protein production by a random regression test-day model.
Test-day genetic evaluation models have many advantages compared with those based on 305-d lactations; however, the possible use of test-day model (TDM) results for herd management purposes has not been emphasized. The aim of this paper was to study the ability of a TDM to predict production for the next test day and for the entire lactation. Predictions of future production and detection of ou...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1998
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(98)75736-4