Estimated Breeding Values


This is a series of quick links to useful resources:

You will find more detail about each of these resources below.

What are breeding values?

EBVs are a tool that can provide you with objective information about a ram's genetic potential. EBVs are particularly useful for traits that are not easy to see on sale day (such as eye muscle depth (EMD) or lamb survival (NLW)). EBVs allow breeders to compare the genetic potential of animals independent of the environment and location.

That said, EBVs are not a substitute for a full visual inspection of your potential ram team. Checking rams for conformation and physical soundness prior to purchase is still essential. Cull faults are cull faults, regardless of how good the EBVs are.  

Everyone's sheep breeding enterprise is unique. We all farm in different environments and there are a host of other factors that determine what our ideal production system is: scale, number of staff, parasites and diseases, market demands, and the 'what gets me out of bed?' factor. EBVs are simply a tool that help to you find the genetics that can produce the sheep that best suits your needs.

EBVs - A Guide for Ram Buyers

This guide includes descriptions of EBVs for key traits and provides tips on how to use genetic correlations to drive genetic gain across multiple traits. 

Breeding Objective Tool

The traits (and EBVs) you choose to put the most emphasis on will depend on your breeding objective. By writing down the breeding objective for your particular production system, you can focus on the traits that are most important to you at ram-buying time. This printable version allows you to capture your breeding objective in writing to refer back to in the future.

A Pocket Guide to ASBVs

This is a quick guide to using breeding values and SHEEP GENETICS. ASBV is the term Sheep Genetics uses for breeding values generated by its MERINOSELECT and LAMBPLAN evaluations. 

ASBV Percentile Band Table

Percentile band tables show the range of breeding values across all sheep in the current year drop. This allows you to see where an animal ranks for a particular trait within the analysis group.

Using a selection index

A selection index can help you balance the traits that are most important to you. EBVs for several traits are weighted and combined to give a single index value for a particular ram.  

There are different kinds of indexes, and the type of index that suits you will depend on your production system. Sheep Genetics provides a range of indexes, depending on your breeding objective.

Bear in mind that indexes are developed for a general breeding objective and can only tell whether the ram you are considering will help you move in the general direction you want to move.  

It is important to check the ram's specific breeding values for traits that are important to you (both desirable and undesirable traits) to make sure there are no unwanted surprises down the track!


MERINOSELECT generates across-flock and across-breed genetic information (in the form of breeding values) for fine-wool sheep in Australasia. The breeding values are updated twice a month by Sheep Genetics, using data submitted by breeders from across the industry. 

Click here for more information about the MERINOSELECT database and using estimated breeding values to assess the genetic potential of fine-wool sheep.