The breeding policy is entirely for maternal trait excellence. SIL dual performance recording is carried out, along with Carla testing for resistance to worms and DNA testing for footrot resistance.
All imported sires are screened for low birth weigths with high growth rates, twinning and Carla and Footrot resistance prior to importation.
In 2013 the Raggity Range flock in Central Otago was added to IDFNZ. Whereas the South Otago flock was graded up from Dorsets, the Raggity Range flock was graded up from a Romney base and are also fully recorded on SIL.
The grade-up policies have enabled the "Kiwi-ising" of the breed for New Zealand's fine and strong wooled sheep industries.