Three models on estimates of variance components and fixed effects on weaning weight of slow growing rabbits population were compared. Measures on weaning weight (W-weight) from 86 progeny of 4 bucks mated with 12 does (3 dams/buck) were collected and sex (Sex), number of progeny weaned (N-weaned), Parity and age at weaning (W-age) were registered. Variance components of W-weight concerned buck-, doe-, error-, phenotipic-, additive genetic-, maternal-, and environmental- variance. Buck- and doe- random components were estimated by REML (REstricted Maximum Likelihood) in a nested design. Analysis was carried out by use of three different mixed models in which (fixed) effects of Sex, number of progeny weaned (N-weaned), Parity and age at weaning (W-age) were considered. In model-1 Sex and Parity were concerned as class variables and W-age as a covariate. In model-2 Sex and N-weaned were concerned as class variables and W-age as a covariate. In model-3 Sex was concerned as a class variable and N-weaned and W-age as covariates. In all models Sex do not showed significant differences. Parity and W-age denoted significant influences in model-1. N-weaned was found significant as a class variable (model-2) and as a covariate (model-3). Heritability (h2) estimates were: model-1=0.31, model-2=0.65 and model-3>1.00, respectively. Sex does not influence W-weight. All models results in estimates of heritability with high standard errors, subjecting need to repeat estimation on more extended data. Model-1, resulted in a more reliable estimate of h2 with respect to others models in which, some variance components were found negatives.
|Autori:||LEOTTA R.; PACI G|
|Titolo:||Estimation of Influence of Genetic and Environmental Factors on Slow Growing Rabbit Population: I. Preliminary Study.,|
|Anno del prodotto:||2007|
|Appare nelle tipologie:||1.1 Articolo in rivista|