Understanding Genetics

Photo: Errol Brumpton uses ASBVs for the modern sheep (Courtesy Qld Country Life)
Photo: Errol Brumpton uses ASBVs for the modern sheep (Courtesy Qld Country Life)

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 Sheep CRC conducts genetic research through its Information Nucleus. This is a group of 8 flocks located across Australia, using many breeds and diverse industry sires to:

  • Establish new traits eg. Intra Muscular Fat and Shear Force (tenderness)
  • Develop genomic (DNA) tests for expensive or difficult to  measure traits
  • Improve the knowledge about genetic parameters
  • Expand the performance data across more bloodlines
  • Increase the availability and accuracy of Australian Sheep Breeding Values.


Choose from the tabs below to find more detailed information.


Practical Wisdom Notes / Fact Sheets

Genomics and DNA testing: new tools for ram breeders to accelerate genetic gain

PW4.1 New Opportunities in Genetics and Genomics

Using ASBVs

Products & Training Resources

ASBV Pocket Guide

Australian Sheep Breeding Values - A guide for ram buyers

Marketing your sheep with genetic data

Reports, Articles and Presentations

Getting Started with Sheep Genetics

Sheep CRC Genomics Breakfast Workshop - LambEx 2012

News Releases

Breeding for flystrike resistance to be made easier
Genetic research into the heritability of flystrike susceptibility in sheep, and its expression in different operating environments, is set to be incorporated into new tools to assist breeders make more informed selection and flock management decisions. Tracie Bird-Gardiner, from the NSW Department of Primary Industries, has spent the last four years collecting and analysing data from fly-struck sheep in the industry’s... Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/breeding-for-flystrike-resistance-to-be-made-easier-24-10-2016.php
Commercial Merino producers - opportunity for DNA pilot project
Commercial Merino producers have the opportunity to be at the cutting edge of DNA research by participating in a pilot trial of the new Flock Profiling Test from the Cooperative Research Centre for Sheep Industry Innovation (Sheep CRC). The Sheep CRC will provide support for up to 100 Merino producers to define the genetic merit of their flocks. The profiling test involves randomly sampling 20 young ewes for DNA testing. Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/commercial-merino-producers--opportunity-for-dna-pilot-project-10-10-2016.php
Understanding why farmers are pressing the app buttons
Despite the proliferation of new technology in agriculture, very little is known about the effectiveness of these new tools in improving primary productivity and adoption of new practices. A new research project from the Cooperative Research Centre for Sheep Industry Innovation (Sheep CRC) will evaluate the use of smartphone apps in the industry and producer attitudes towards these tools, in order to ensure future tools and... Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/understanding-why-farmers-are-pressing-the-app-buttons-22-09-2016.php
Ram team records unlock the secrets to better breeding
Keeping accurate records of his ram teams has allowed South Gippsland second-cross lamb producer Paul O’Sullivan to benchmark his business against industry averages and to refine his genetic selections to take flock productivity to the next level. Mr O’Sullivan was impressed by the benchmarking capabilities of the new RamSelect Plus app when it was launched at LambEx by the Cooperative Research Centre for Sheep Industry... Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/ram-team-records-unlock-the-secrets-to-better-breeding-16-09-2016.php
Sheep breeders rush to RamSelect Plus
Sheep breeders are embracing RamSelect Plus in droves, with close to 4000 rams from 60 different studs listed on the site since the start of July. And there are already over twice the number of registered users than there were at the end of the 2015 ram-selling season. Sheep CRC chief executive James Rowe said the early-season figures were a strong endorsement of the need for easy-to-use applications that provide personalised... Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/sheep-breeders-rush-to-ramselect-plus-29-08-2016.php
UNE app development team leads the way for the sheep industry
The team behind the popular web-based app RamSelect Plus is already turning its attention to finding new solutions to the data challenges facing the sheep industry. The next project on the cards for the University of New England (UNE) Agile App team is to develop an early intervention sheep management app for the Cooperative Research Centre for Sheep Industry Innovation (Sheep CRC) so that producers can ensure all animals in... Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/une-app-development-team-leads-the-way-for-the-sheep-industry-22-08-2016.php
RamSelect Plus adds new precision to genetic selection
Producers at this week’s LambEx event have early access to RamSelect Plus, the latest version of the popular sheep genetic selection app. Cooperative Research Centre for Sheep Industry Innovation (Sheep CRC) CEO James Rowe said RamSelect Plus features more precise genetic selection tools, as well as new benchmarking and ram team management tools. Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/ramselect-plus-adds-new-precision-to-genetic-selection-10-08-2016.php
DNA Flock Profiling delivers sheep breeding insights at Europambela
New England Merino breeder Tony Overton has a much clearer picture of the genetic make-up of his superfine Merino flock and the areas which need attention following trials of a new application for the 15k DNA test designed specifically for commercial producers. Mr Overton, who manages 9000 ewes at ‘Europambela’ in the Walcha district, was a participant in early field trials of the DNA Flock Profiler, being developed by... Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/dna-flock-profiling-delivers-sheep-breeding-insights-at-europambela-22-07-2016.php
Got ram team records? Sheep CRC needs you!
Sheep breeders with comprehensive records of their ram teams are being sought by the Sheep CRC as it enters the final stages of development of the latest RamSelect app. The next version of RamSelect will feature enhanced ram searching capabilities to align with estimates of the current genetic merit of a commercial ewe flock, either based on records of the rams used during the previous 10 years, or using data obtained through... Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/got-ram-team-records-sheep-crc-needs-you-13-07-2016.php
Sheep DNA tests now quicker and easier
DNA testing of sheep is now quicker and easier than ever, following moves by the Sheep CRC to simplify the process for breeders. From July 1 producers will be able to purchase a stock of blood cards to keep on hand on their properties, allowing them to take blood samples at their convenience, such as at lamb marking, and only submit those they are most interested in for analysis at a later date when they consider their... Click Here To Read Full Article » http://www.sheepcrc.org.au/information/news/sheep-dna-tests-now-quicker-and-easier-30-06-2016.php
Click Here To Read More News Articles »

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