Breeding value evaluation in Polish fur animals: Estimates of (co)variances due to direct and litter effects for fur coat and reproduction traits

Abstract

5 540 records of the arctic fox fur coat and reproductive traits collected in 1983-1999 were studied. The analyzed traits were: body size (BS), colour type (CT), colour purity (CP), coat density (CD), hair length (HL), general appearance (GA), total score (TS), skin length (SL), litter size at birth (LSB), litter size at weaning (LSW), number of dead pups (NPD), pup weight at weaning (PW), and pregnancy length (PL). (Co)variance components were estimated using a derivative-free algorithm of REML and a multi-trait animal model. Random effects were direct additive, common litter environment and residual. The genetic parameters for the fur coat traits (discrete characters) were estimated twice: using the original data set, and the data set in which the distribution of fur coat scores was normalised using a probit link function. Direct heritability estimates obtained from the original data set ranged from 0.108 for SL to 0.276 for HL, and were somewhat lower than those estimated using the transformed data set (they ranged from 0.109 for GA to 0.315 for CT). Reproductive traits were lowly heritable with direct heritabilities ranging from 0.060 for PW to 0.174 for LSB. Estimates of the portion of litter variation calculated from the original and transformed data set were comparable ranging from 0.045 for GA to 0.156 for CP, and from 0.059 for GA to 0.185 for TS, respectively. Genetic correlations between fur coat traits ranged from high favourable (0.948 between SL and BS, original data) to strong negative ones between CP and GA (-0.405, transformed data). High positive genetic correlations were found between LSB and LSW (0.954), and between LSB and NPD (0.783), whereas PL was negatively correlated with all other reproductive traits.

Genetic parameters for fur quality graded on live animals and dried pelts of American mink (Neovison vison)

“…The effects were greater for weight and skin size, where c 2 = 0.14 and 0.12 for male and female weight, respectively, and c 2 = 0.12 and 0.08 for male and female skin size, respectively. These results were congruent with those previously reported in mink (Berg, ,b; Koivula et al., , ; Lagerkvist & Lundeheim, ) and fox (Peura et al., ; Wierzbicki & Jagusiak, ). Our results indicated fur quality traits were not strongly affected by dam or litter mates as was weight and size.…”

Joint breeding value evaluation for fertility in Finnish and Norwegian blue foxes

“…We obtained slightly higher heritability estimates for LSs than found in earlier studies, where heritabilities for LS1 and subsequent litter sizes (recorded at age of about 10–21 days) have varied from 0.08 to 0.11 (Kenttämies, ; Koivula et al, ; Peura, Strandén, & Mäntysaari, ; Peura et al, ; Wierzbicki & Jagusiak, ). The difference with our results may arise from the better quality of the data in this study.…”

“…This is an unexplored topic that requires further study. Wierzbicki and Jagusiak () showed in a study on Polish blue foxes that LS at birth and early neonatal mortality has a genetic background, with heritabilities of 0.17 and 0.09, respectively. It should therefore be possible to improve these traits by selection.…”

Variation in fur farm and wild populations of the red fox, Vulpes vulpes (Carnivora: Canidae) — Part I: Morphometry

“…In the case of artificial selection (carried out by breeders), the correlated response leads to changes in the traits that are genetically correlated and are improved through selection (Prasad et al 2001;Le Gac et al 2013). This is confirmed by Wierzbicki and Jagusiak (2006) in a farm population of the Arctic fox (Vulpes lagopus). The authors estimated genetic correlations among eight traits of exterior and coat cover and five reproductive traits.…”