Variance Components of litter size in Icelandic farmed mink (Neovison vison)

Abstract

An analysis of variance components and a study of pedigree structure was carried out using Icelandic field data. Data from six farms was included, total of 88°928 animals in the pedigree. Two methods were employed, MCMC Gibbs sampler method and REML. The two different methods gave similar results. Heritability (0.03-0.06) and repeatability (0.08-0.16) was lower than in previous studies. EVA software was used to estimate pedigree structure. Average inbreeding was low (0.015). Data suggests that inbreeding is underestimated with the current data recording system. Average inbreeding coefficient decreases after the onset of large scale import of Danish male. The Danish males enter the system as animals from the base population. Full pedigree information should be used for animals if inbreeding is to be controlled. Genetic variance is variable but lower than earlier results. This could be explained by the Bulmer Effect. Phenotypic variance is higher on Icelandic farms than on Danish farms. To ensure optimal calculations of EBV’s; these results should be taken into account in the calculations of EBV’s. Farmers should be advised to standardize their data recording, count the kits at 3 weeks post-partum. Effect of different parameterizations on variance components should be investigated, especially in regard to feed stations.