Impact of missing pedigree and missing early lactation records on the genetic evaluation of 305-day milk yield in Friesian cattle
Abstract: The aim of this study was to investigate the effect of missing sire pedigree, missing early production records and types of models on estimating heritability, variance components and breeding values of 305-day milk yield (M305). Data was covered by a period of 41 years making "10041 records of 3500 Friesian cows progeny of 323 sires and 2364 dams. Two types of models; animal-sire-dam model (ASD) and animal-sire-maternal grand sire model (ASM) were applied. Estimates resulted from the ASD model with zyro% missing information was considered as the standard case of this study, (ASD00) and was used to compare estimates resulted from other cases. For missing sire pedigree, two ratios of missing sires were applied at random (25% and 50% ) .and for missing early lactation records two ratios were also applied randomly, (10% and 25%). Single Trait Animal Model was used to estimate variance components, heritability and breeding values of all animals for M305 considering the animal, sire and dam (or MGS) as random effects. Estimates of heritability and variance components resulting from all the scenarios were compared with the estimates of the standard case (ASD00) with complete information and pedigree. The biasness was calculated and analyzed. Results of bias analysis showed non-significant differences among scenarios of missing sire pedigree. Additive genetic variances and heritability estimates decreased as the percentage of missing sire pedigree increased except for heritability estimate of the ASM25. Also, additive genetic variances and heritability estimates decreased as the percentage of missing early lactation records increased in the scenarios of ASD model. Scenario of animal sire maternal grand sire model with zero missing pedigree (ASM00) has the smallest bias in most estimates except for estimating environmental variance. Also, estimates of ASM with 25% missing pedigree (ASM25) had less bias than estimates of ASD25. Therefore, the ASM model could be an alternative for ASD model without having a serious effect on estimating variance components and heritability.
Keywords: Dairy cattle, genetic evaluation, animal model, missing sire pedigree, missing lactation records.
Publication year 2013
Pages 1-8
Availability location معهد بحوث الانتاج الحيوانى-شارع نادى الصيد- الدقى- الجيزة
Availability number
Organization Name
serial title The 4th Scientific Conference of Animal Production Research Institute (APRI)
Author(s) from ARC
External authors (outside ARC)
    منال الصياد جامعة عين شمس
Agris Categories Animal husbandry
AGROVOC
TERMS		 Animal models. Cows. Dairy cattle.
Proposed Agrovoc missing lactation records;mmissing sire pedigree;genetic evaluation;
Publication Type Conference/Workshop
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