Maternal Grandsire Model for Dairy Sire Evaluation
نویسندگان
چکیده
منابع مشابه
Implementation of a sire-maternal grandsire model for evaluation of calving ease in the United States.
The objective of this study was to add a maternal grandsire (MGS) effect to the existing sire model for national calving ease genetic evaluations. The Animal Improvement Programs Laboratory (AIPL) of USDA assumed responsibility for conducting the national genetic evaluation for calving ease and maintaining the associated database in 1999. Existing evaluations used a sire threshold model. Adding...
متن کاملGenetic evaluation of stillbirth in United States Holsteins using a sire-maternal grandsire threshold model.
A sire-maternal grandsire threshold model was used for genetic evaluation of stillbirth in US Holsteins. Calving ease and stillbirth records for herds reporting at least 10 dead calves were extracted from the Animal Improvement Programs Laboratory database. About half of the 14 million calving ease records in the database had a known livability score, mostly from herds processed by Dairy Record...
متن کاملCalving ease (Co)variance components for a sire-maternal grandsire threshold model.
Variance components for a sire-maternal grandsire (MGS) threshold model were estimated from subsets of the US calving ease (CE) database, which includes over 10 million calving records with CE scored 1 (no problem) to 5 (extreme difficulty). Selected records included sire and MGS among the 2601 most frequently appearing bulls. The data were further restricted by requiring at least 20 records in...
متن کاملGenetic parameters of calving ease using sire-maternal grandsire model in Korean Holsteins
OBJECTIVE Calving ease (CE) is a complex reproductive trait of economic importance in dairy cattle. This study was aimed to investigate the genetic merits of CE for Holsteins in Korea. METHODS A total of 297,614 field records of CE, from 2000 to 2015, from first parity Holstein heifers were recorded initially. After necessary data pruning such as age at first calving (18 to 42 mo), gestation ...
متن کاملTechnical note: adaptation of an animal-model method for approximation of reliabilities to a sire-maternal grandsire model.
A method used to approximate reliabilities for animal models was modified to estimate reliabilities for sire-maternal grandsire (MGS) models. Accuracy of the approximation was tested on a calving-ease data set for 2,968 bulls for which the inverse of the coefficient matrix could be obtained. Correlations between estimated and true reliabilities ranged from 0.984 to 0.998 for first- and later-pa...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1979
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(79)83476-1