For the Norsvin lines, Norwegian and international herds comprise the Norsvin nucleus populations. Herds are linked together genetically by AI and central testing. Norsvin collect a large amount of production data from Norwegian, as well as foreign breeding herds.
Norwegian Nucleus Herds
There are 46 Norwegian nucleus herds. Their main role is to run the nucleus breeding program and deliver candidates to the boar test (Landrace and Duroc). In addition, Landrace herds produce purebred sows for sale to contracted multipliers. Data registrations in the nucleus herds serve as an important fundament for the EBV calculations. Young Landrace and Duroc boars are recruited from the nucleus herds, and follow a strict selection pathway (performance test) after which the best 3 % end up as AI boars (boar sires).
There are 74 contracted multiplier herds selling crossbred LY gilts (Landrace x Yorkshire) to ordinary production herds. Data from the multipliers is used estimating EBV’s for the animals in the nucleus herds.
Internationally, Norsvin breeding herds are found in the US, Sweden, Lithuania and Spain.
Sustainable balance between genetic progress and inbreeding is now maintained by utilization of the optimal contribution theory – dynamic selection rules by placing a direct constraint on cumulative inbreeding.
Norsvin and partners strive to keep the genetic lag to a minimum between the core development and R&D in Norway, and commercial production.