Inbreeding depression for litter traits and the development of growth in the Gottinger Minipig

A data set of 1191 litters from 282 sows and 6777 piglets weights from the Gottinger Minipig was analysed to estimate inbreeding depression for litter traits and the early growth rates up to an age of 12 month. The population of the Gottinger Minipig shows an average inbreeding of sows and piglets o f about 10% with a standard deviation of 1.7% with a nearly normal distribu tion of the inbreeding coefficients in contrast to most other studies about inbreeding depression. There is no inbreeding depression observed for numb er of piglets born alive or born dead within a litter, neither for inbreedi ng of sows nor for inbreeding of litters. For average and individual birth weights the inbreeding of sows show a significant influence while the inbre eding of the litter is not significant. With a 10 percent increase of the i nbreeding of sows a reduction on individual birth weight of 70 gram is obse rved (70% of the phenotypic standard deviation). For the weight of piglets in the first 6 month both the inbreeding of sows and the inbreeding of litt ers show a significant effect. A 10 percent increase of inbreeding of sows or litters both leads to a reduction on weight within the first 6 month of 250 gram (20% of the phenotypic standard deviation.