Naslov
Estimation of dispersion parameters for number of piglets born alive using a random regression model

Autori
Luković, Zoran ; Gorjanc, Gregor ; Malovrh, Špela ; Kovač, Milena

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
4th International Workshop on Data Management and Genetic Evaluation in Pigs : Book of Abstracts / Malovrh, Špela ; Kovač, Milena - Domžale : Biotechnical Faculty, Zootehnical Department, 2004, 56-57

ISBN
961-6204-20-3

Skup
International Workshop on Data Management and Genetic Evaluation in Pigs (4 ; 2004)

Mjesto i datum
Domžale, Slovenija, 15.04.2004. - 18.04.2004

Vrsta sudjelovanja
Demonstracija

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Random regression; genetic parameters; litter size; pigs

Sažetak
Dispersion parameters for number of piglets born alive (NBA) were estimated using random regression model (RRM). Litter records from two datasets from Nemščak farm in Slovenia used for analyses. The first dataset (DS1) included litter records from first to sixth parity. Second one (DS2) was extended to tenth parity in order to verify possibility for selection on persistency in litter size. Litter records from four sow genotypes were included: Swedish Landrace (SL), Large White (LW) and both crossbred. Fixed part of the model included sow genotype, mating season (month-year interaction), parity and weaning to conception interval as class effects. The age at farrowing was adjusted as quadratic regression nested within parity. Previous lactation length was fitted as linear regression. Random regressions on Legendre polynomials were included for direct additive genetic, permanent environmental, and common litter environmental effect. Orthogonal Legendre polynomials from the linear power to cubic power were fitted. Estimates of heritability ranged from 0.09 to 0.14. Permanent environmental effect as ratio increased along trajectory from 0.05 to 0.16. Magnitudes of common litter effect were generally small (0.01 to 0.02). The eigenvalues of covariance functions showed that between 10 and 15% of genetic variability was explained by individual genetic curve of sows in the DS2. This proportion was mainly covered by linear and quadratic coefficients. The solutions for the random regression coefficients were used to compute breeding value for NBA along trajectory. Results suggest that RRM could be used for selection on persistency in litter size.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

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