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CPT Artificial Insemination 2023

The time has come around again for Sheep Ireland’s  Central Progeny Test (CPT) programme 2023-2024 breeding season. The CPT is a critical element of the National Sheep Breed Improvement program and is a huge source of commercial data each year.

In order to ensure the genetic evaluations, Sheep Ireland runs a CPT which is facilitated by the use of Artificial Insemination (AI).

Among the 2 CPT farms, almost 400 ewes were inseminated last week with fresh semen from 7 LambPlus breeders’ high replacement Index rams:

   *click on their names to view the €uroStars of each ram.

Sheep Ireland’s Central Progeny Test (CPT)

The CPT was established in 2010 and its main function was to fast track and maintain genetic linkage among performance recording flocks in Ireland. It carries out this function by bringing together influential bloodlines across the most widely used sheep breeds in Ireland and using them together across commercial ewes contracted by Sheep Ireland to carry out intensive performance recording.

Ewes are impregnated by AI using semen collected from these pedigree rams. A number of carefully selected rams are also purchased by Sheep Ireland annually and used via natural mating within these CPT flocks. This work all contributes to delivering the most accurate €uroStar evaluations as possible to Irish sheep farmers.


When it comes to flock linkage, there are three possible categories;

  • Linked – The ideal situation for performance recording flocks. Your flock is being compared to all other performance recording flocks within your respective sheep breed.
  • Weak Linkage – Your flock linkage status is weakening. You may have been linked last year. You should act during the next mating season to prevent your flock from becoming unlinked.
  • Unlinked – Your €uroStar evaluations are within flock evaluations and are not comparable to other breeders within your respective sheep breed, this will be reflected in how your €uroStars will be displayed for the season ahead.

In the example below Link Ram 1 is the most connected ram as it has been used in most flocks including the CPT, this ram is likely to have the highest accuracy, meaning his evaluation will be more dependable.

Home Ram A, B, C & D have all only been used in one flock but are still linked because a second ram has also been used in the flock and that second ram has also been used in another linked flock.

Home Ram F is not linked, therefor the lambs in this flock will not be linked and the data collected in this flock will be of limited use in the evaluation.