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Comparison of different variance component estima · tion methods for genetic parameters of clutch pattern in laying hens Vergleich verschiedener
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ünver, Yakut Oğuz, I. Altan, Özge |
| Copyright Year | 2014 |
| Abstract | New selection traits are searched in poultry breeding to improve egg production. Egg production in laying hens is a process of pronounced cyclic nature and eggs are laid at intervals of around 24 to 27 h. This process results in the formation of clutches. To describe the cyclic laying process, some clutch traits are defined as clutch number, average clutch size and mean pause days between clutches. The clutch traits have been investigated only by a few researches in different domestic avian species in recent years (AGGREY at al., 1993; Luc et al., 1996; BEDNARCZYK et al., 2000; NESTOR et al., 2000). Heritabilities of clutch traits and their genetic correlations with other traits should be estimated to evaluate the clutch traits as selection criteria for layers. Several researches have been conducted to investigate the heritabilities of clutch traits. Heritabilities of different clutch traits varied from a low to a moderate level (McCLUNG et al., 1976; Luc et al., 1996; BEDNARCZYK et al., 2000). Phenotypic and genetic ( co )variance components are ex tensively used in animal breeding for estirnation of heritability, breeding value, for planning breeding programs and interpretation of the genetic mechanisms of quantitative traits (HENDERSON, 1986). Several variance and covariance component estirnation methods are available. Type 1 is the analysis of variance method which gives unbiased estimation only for completely random models, but is easiest to compute (SCHAEFFER, 1983, HENDERSON, 1984). The type II method is not an appropriate method for models including interactions between fixed and random factors or where random factors are nested within fixed factors. Type ill method can be used for unbalanced data set and is known as "fitting constants" method which is suitable for mixed models (HENDERSON, 1953). Traditionally, hierarchical sire and sire dam models on the base of Type m variance components estimation method are common in domestic fowl (MIELENZ et al., 1994). Likelihood based methods (ML and REML) became more popular than the others. RAo (197la, b) and LAMOTTE (1971) have independently developed methods called MNQUEO and MINQUE (HOFER, 1998). MIVQUE stands for Minimum Variance |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.european-poultry-science.com/artikel.dll/2002-66-232-236_NDk2MDc4NQ.PDF |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
