Linkage

Linkage is where genes are represented across multiple environments, generally through the use of common sires between flocks, years and groups. Linkage provides a genetic benchmark so that genetic merit can be compared across flocks and environments, allowing the delivery of across-flock ASBVs.

Sheep Genetics recommends routinely using genetics that have been in other Sheep Genetics flocks, that are recording traits relevant to your recording program. Linkage is calculated at a trait level, using the last five years of pedigree, so it is important to regularly introduce link sires that have been recorded for the traits you are recording.

Where do I need linkage?

Linkage is required:

between flocks – genetics measured in your flocks and in other Sheep Genetics flocks
between years – common sires across years
between groups – common sires across management groups.

Do I need to be linked for all traits?

To be linked for a trait, the link sire needs to provide a genetic link for the trait. This sire needs to have progeny recorded for the traits you’re recording in another Sheep Genetics flock.

Strong linkage with other flocks and between years is important. Strong linkage with other flocks and between years is important in providing an across-flock evaluation.

Ways to ensure across-year and across-group linkage

Rule of thumb: For every 10 sires used, use at least one sire from the previous year in your current drop
Have multiple sires represented in each management group and ensure there are common sires between groups.

Ways to ensure across-flock linkage

For every 10 sires make sure one has been used in other Sheep Genetics flocks. Artificial insemination (AI) is a good way for many breeders to use the same sires.
Buy new sires (or semen) from other flocks which have data in Sheep Genetics and are linked for the traits you are interested in.
Sell rams to other Sheep Genetics flocks for use and record as sires.
Participate in a Young Sire Program which shares young sires across flocks
Enter a sire into a sire evaluation, Resource Flock or progeny test
Enter a sire into a sire evaluation program or Resource Flock
Rule of thumb: have at least 30 progeny from each link sire

Sheep Genetics QA protocols

Ensure any link sire is recorded for the traits you are recording
Ensure any link sire has effective progeny numbers in your drop