Norwegian pig breeding is organized as a traditional pyramid.
The nucleus herds produce Norsvin Landrace and Norsvin Duroc boars for boar testing, recruit their own breeding sows and sell Landrace sows to multiplier herds.
The multiplier herds purchase on-farm tested and exterior-evaluated Norsvin Landrace gilts from the nucleus herds. These sows are inseminated with Yorkshire semen to produce hybrid (Norsvin LY) sows. The hybrid sows are sold on to production herds. The multiplier herds are thus responsible for ensuring that genetic improvements are propagated to the production herds.
The production herds account for the bulk of pig production in the country, and so constitute the main target group for the breeding work. Norsvin’s system of breeding herds now comprises 30 Norsvin Landrace nucleus herds which supply boars for testing, and eight Norsvin Duroc herds. There are also six Landrace nucleus herds which do not supply boars for testing; these are SPF nucleus herds and herds in the north of Norway. There are 60 multiplier herds in the present system. At the bottom of the pyramid are 1 400 piglet and combined producers and 1 400 finishing herds.