Breeding using Genetics

Understanding Genetics

Genetics is the knowledge of how genes affect the way an animal looks or performs. It includes ‘heritability’, which describes how much of a trait is passed on from the parent to the offspring and ‘correlation’, which explains how one trait is related to another.

A wealth of genetics knowledge already exists and allows us to predict the performance of progeny, based on the performance of their sire or dam and other relatives.

The genetic merit of sheep and their estimated breeding values are predicted by directly measuring the performance of traits at particular times or by using indirect measures of a trait, that is, information about other traits that are related to the trait in which we are interested.

However, a sheep’s own performance is the result of both its genetics and the ‘environment’. The important environmental influences include nutrition, climate, diseases and parasites, whether the animal was a single or twin, whether its dam was a mature ewe or a maiden, its sex, its age relative to its flock mates and other factors about how the animal was managed.

To predict the performance of a sheep’s progeny based on its genetics, we need to exclude the environmental factors. Also, to increase the accuracy of this information we include performance data from its relatives: its sire and dam, siblings and half-sibs (i.e. brothers and sisters and half-brothers and half-sisters) as well as other relatives, especially the individual’s own progeny.

The result calculated is the ‘estimated breeding value’. For sheep in Australia, this is calculated and published as an Australian Sheep Breeding Value (ASBV) in LAMBPLAN (for meat sheep breeds) or MERINOSELECT (for Merinos). When ASBVs are calculated they also incorporate all that is known about the heritability of a trait and the correlations it has with other traits.

ASBVs are more accurate than using the raw measurement from a trait, especially for traits that have lower heritabilities, a smaller range of expression or lower accuracy of measurement. ASBVs also allow unrelated animals from different studs under different management conditions to be compared objectively.

ASBVs are only available for sheep when performance data has been collected using procedures outlined in the Sheep Genetics’ Quality Assurance Manual. Many sheep studs provide ASBVs for a range of traits on each of their sheep.

The following pages give outlines on breeding for specific products, however, producers can breed for a combination of these. In particular, wool ram breeders are increasingly including more emphasis on meat characteristics within their selection program to reflect the importance of sale sheep income within the wool production enterprise.

Whether the focus is on meat or wool, disease resistance and fertility are also important traits to include.

To find out detailed information on breeding click on the headings below:


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Practical Wisdom Notes / Fact Sheets

PW4.1 New Opportunities in Genetics and Genomics

In this series:

  1. Genomics and DNA testing: new tools for ram breeders to accelerate genetic gain
  2. Breeding towards a poll flock with the Sheep CRC Poll test

  3. Sheep CRC genomic test for Merinos —what are the benefits?

  4. Sheep CRC genomic test for maternal breeds —what are the benefits?

  5. Sheep CRC genomic test for terminal breeds —what are the benefits?

  6. Using Australian Sheep Breeding Values

  7. Fat and eye muscle depth in Merino breeding programs

  8. Benefits of Reproductive Technologies in  Closed Nucleus Sheep Breeding

  9. Merinotech: Strategies to achieve a 100% PP nucleus

  10.  Using selection decisions to improve ASBVs

  11. Genomic testing ram lambs helps increase rates of index genetic gain by 50% at Centre Plus

Products & Training Resources

ASBV Pocket Guide

ASBVs - A guide for ram buyers

Sheep DNA Testing Information

News Releases

DNA Flock Profile cements the foundations for new flock
Developing a flock with the right mix of genetics can take generations to perfect, but DNA testing has put Geelong sheep and wool producer Jack Briscoe on the fast track to success. Mr Briscoe is only a year into breeding his own Merino flock after branching out from his sheep contracting business by cobbling together a mixture of 800 home-bred and yard-bought ewes as his breeding base. Click Here To Read Full Article »
RamSelect keeps track of flock performance at Parkes
The RamSelect app is not only assisting with better genetic decisions for the Dunn family of Parkes, NSW, but also assisting with their inventory management and industry benchmarking activities. The Dunn family, trading as Reedy Creek Partners, operates a mixed farming enterprise between Manildra and Parkes, and has been using the app since it was first launched in 2015 to assist with their ram selections. Click Here To Read Full Article »
Faster sheep DNA testing with new Australian GeneSeek lab
Sheep breeders using DNA testing to improve their genetic selections can look forward to faster turnaround times for test results thanks to Neogen Corporation’s decision to establish a genomic testing laboratory within Australia. GeneSeek Australasia, a wholly owned subsidiary of United States-based parent company Neogen, has acquired the assets of the Animal Genetics Laboratory (AGL), based at the Gatton campus of the... Click Here To Read Full Article »
Dramatic increase in early season searches on RamSelect
Inquiry for rams through RamSelect has never been stronger with a dramatic increase in the number of buyers searching the site so far this season compared to last year. More than 1129 ram searches were conducted on RamSelect during July, compared to just 154 at the same time last year. Click Here To Read Full Article »
DNA testing to drive new era of ewe competitions
The traditional ewe competition is set to enter the innovation era with the inclusion of DNA Flock Profile tests as part of next year’s Doug Bicket Memorial Ewe trial in Parkes, NSW. The Cooperative Research Centre for Sheep Industry Innovation (Sheep CRC) will provide DNA profiling for all flocks entering the 2018 competition, currently valued at $800 plus GST per flock, as a means of supporting improved genetic selection... Click Here To Read Full Article »
The predictive power of ASKBILL immortalised in song
An off-the-cuff comment and a spur of the moment decision to “have a go” have resulted in the sheep industry’s new predictive app, ASKBILL, being brought to life in song by Uralla musician Rhonda Brooks. Performed in a bush ballad style by Coffs Harbour musician Mal Winckle, the track is proving a popular addition to the ASKBILL website, helping to capture producers’ imagination as to the possibilities on offer... Click Here To Read Full Article »
RamSelect moves towards commercial business model
The popular RamSelect app will move to a commercial funding model ahead of this season’s ram sales, as a first step towards ensuring the genetic selection tool’s financial viability and availability to producers in the long-term. RamSelect Plus is an easy to use web-based application,, which allows ram buyers to find and rank rams based on Australian Sheep Breeding Values (ASBVs) that match their own... Click Here To Read Full Article »
Faster, more accurate DNA Parentage and Poll test to be released in July
Sheep breeders will have access to a faster, more accurate DNA test for parentage and poll/horn status from July, which also includes new features to detect a range of genetic defects. First launched in 2012 by the Cooperative Research Centre for Sheep Industry Innovation (Sheep CRC), the DNA Parentage and Poll test has proven very popular with sheep breeders seeking to improve their genetic selections through more precise... Click Here To Read Full Article »
‘Eye opening’ DNA Flock Profile delivers new breeding insights at Beechworth
DNA testing to obtain a genetic flock profile has changed the way Victorian Merino breeder Stuart Warner not only looks at his flock, but how he will approach his genetic selection decisions in the future. As a registered deliverer of Bred Well Fed Well and RamSelect workshops, Mr Warner has a close understanding of the power of Australian Sheep Breeding Values (ASBVs) as an objective genetic selection tool. Click Here To Read Full Article »
The power of prediction now in sheep producers’ hands – just ASKBILL
A new app launched today will give sheep producers the power to see their stock’s future, all from the palm of their hand. The app, available at, was made live to the public today, marking the start of a limited offering of the ASKBILL platform as part of a pre-release user feedback program – a vital step in putting the finishing touches to the product prior to ASKBILL’s full commercial release later... Click Here To Read Full Article »
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