Background

A progeny test is used to “prove” the genetics of a ram by comparing how his progeny perform under the same environmental conditions relative to progeny from other rams. Rams can be compared across different flocks through use of reference sires that create genetic links between flocks. However, there are good reasons to run a progeny test at one location, usually termed a “central progeny test” (CPT). Reasons include facilitating comparisons of rams that would not normally be made in industry, and the use of novel or expensive measurement methods.

Objectives

The Beef + Lamb New Zealand CPT was set up to:

examine how much industry rams varied in carcass merit, using a sophisticated approach to carcass assessment (i.e. VIAscan)
demonstrate to industry the extent to which rams varied in the value they could add to farm returns
improve our understanding of the genetic control of carcass merit and it’s relationship with other production traits
foster links between ram breeding groups

The CPT was NOT set up as a breed comparison, but rather as a RAM comparison. It has focused on what are considered to be better genetics. Breed comparisons require testing of many sires per breed, selected at random from within each breed, and with fewer progeny per sire. The CPT has used a small number of sires with more progeny per sire, from as many breeds as possible to improve genetic linkage within the New Zealand Sheep Industry.

Genetic links between breeding groups established through the CPT have been used in large scale evaluations performed across flocks and across breeds by SIL. These are the “SIL-ACE” (Advanced Central Evaluation) evaluations. CPT data has provided the links necessary for this to be undertaken.