Genetics of litter size, age at first insemination and animal size in blue fox (Alopex lagopus)

摘要

Skin size of blue fox has increased considerably in Finland during the last decade. This may have lead to decreased fertility through unfavourable genetic correlation. The average number of pups per mated females has slightly decreased after the mid-90's. The objective of this study was to estimate the genetic parameters of the first three litter sizes, female age at first insemination and animal size using REML with single and multitrait animal models. The data was obtained from the Finnish Fur Breeders' Association. In the single trait analysis data and pedigree had 30268 and 44297 animals in litter size, 46295 and 62035 animals in age at first insemination and 68108 and 78775 animals in animal size, respectively. Multitrait analysis had 9126, 5115, 2525, 15381 and 23574 observations in 1st, 2nd and 3rd litter size, age at first insemination and animal size, respectively. Pedigree had 32356 animals in the multitrait analysis. Heritability estimates were 0.08, 0.08 and 0.07 for first, second and third litter size, respectively. Heritability estimates in single and multitrait analysis were 0.16 and 0.18 for age at first insemination and 0.24 and 0.25 for animal size, respectively. The genetic correlations between animal size and age at first insemination and first, second and third litter size were-0.20,-0.40,-0.40 and -0.23, respectively. Genetic correlations between first and second litter size were 0.62, between first and third 0.51, and between second and third 0.60. This study supports the conclusion that there is an antagonistic genetic correlation between fertility and animal size.