With the advent of new and cheaper genetic technologies, the sheep industry is now on the verge of molecular and genetic identification of superior animals.
We will soon see the availability of a huge range of genetic markers for research purposes and in coming years commercial and affordable tests will be available for sheep breeders to identify particular characteristics in their sheep without the extended time and costs associated with progeny testing or maintaining a large number of animals until the desired characteristic is expressed, measured and then compared.
Also, our results will increase the accuracy of current Australian Sheep Breeding Values (ASBVs) and assist in developing new ASBVs based on phenotypic measures.
To capitalise on the molecular genetic opportunities, the Sheep CRC will be looking to identify a range of traits through genetic markers. Naturally, these include some of the characteristics we already know and measure, such as eye muscle depth, fibre diameter and reproductive performance.
In addition, the Sheep CRC research programs aim to improve the ability of wools to deliver predictable next-to-skin comfort and dye-ability, for our meat to come from high yielding carcases with desirable nutritional qualities and for our sheep to be more resistant to parasites and better mothers. So these are the other types of characteristics we expect to be able to identify through new phenotypic or molecular (DNA) tests. The CRC for Sheep Industry Innovation aims to develop appropriate molecular genetic tests that can be used to enhance the current Australian Sheep Breeding Values (ASBVs) as a means to identify the genetic merit of animals.
The Information Nucleus is the key means to investigate and develop these tests. The sheep involved in the Information Nucleus will also be used to investigate some management options. There is a close relationship between the CRC for Sheep Industry Innovation, Sheep Genetics and the Sheep Genomics Program (SG) , with the work of each being complementary, not duplicated.
It is important to note that this new program will not disseminate genetics and will not be producing or advocating a new breed or type of sheep, rather the tools developed will allow industry and its individual breeders to better pursue the breeding direction that is of value to them and their commercial clients.
How will the Information Nucleus help breeders?
Key young sires and some excellent proven older sires from industry flocks are selected annually for progeny testing in the Information Nucleus. Their progeny phenotype information will be included immediately in the Sheep Genetics database and contribute to ASBVs. Their additional progeny will increase the accuracy of the sire ASBVs as well as the accuracy of ASBVs for other related animals, because of the greater across-flock linkages. New traits that prove valuable to industry can be added directly to Sheep Genetics. A major advance will be the validation of markers that will contribute to the development of molecular estimated breeding values. These may be eventually incorporated where appropriate into enhanced ASBVs that can be used to accurately select animals at a very young age and further increase the rate of genetic improvement.
What is the Information Nucleus?
The Information Nucleus comprises eights flocks of ewes across Australia, with a total of 5000 ewes, mated to 100 industry sires annually for 5 years to generate a diverse range of phenotypes and massive amounts of genetic information with which to develop new and improved breeding values. Research stations are essential homes for these flocks as the collection of data is labour-intensive and expensive and is disruptive to normal commercial management. Industry is involved as the sires used are chosen from industry. The Information Nucleus sheep will not just have the meat and wool tests done that we see in modern ram-breeding flocks, but will have more monitoring and more intensive procedures and new tests carried out at more frequent intervals, which require staff with specialist skills and equipment that are not currently mainstream, practical or affordable in the wider industry, but which will ultimately develop tools that are practical and affordable.
The research stations where the sub-flocks have been run are:
|Kirby Research Station, UNE, Armidale||Trangie Agricultural Research Centre, NSW DPI, Trangie|
|Cowra Agricultural Research/Advisory Station, NSW DPI, Cowra||DPI Hamilton Centre, DPI VIC, Hamilton|
|DPI Rutherglen Centre, DPI VIC, Rutherglen||Struan Research Centre, SARDI, Struan|
|Turretfield Research Station, SARDI, Rosedale||Great Southern Agricultural Research Institute, DAFWA, Katanning|
While there are eight locations, there will be five 'sub-flocks', as the two NSW DPI sites, the two SARDI sites and the two DPI Vic sites are each run as one. These sites represent a range of different environmental conditions across Australia, being particularly important for assessment of the interactions of genetics with the environment.
At this stage the flock will be mated five times.
What sires have been chosen?
Approximately 100 sires are used across the 5000 ewes each year. In successive years a proportion of these sires will have been used in one or more previous years to give the necessary across-year genetic linkages. The sires were chosen by a team comprising experts in genetic analysis, representatives from each of the sites, and Sheep Genetics staff who have a very strong knowledge of the sires and studs that are part of the Sheep Genetics' database. Almost all sires chosen were already recorded in the Sheep Genetics databases (either LAMBPLAN or MERINOSELECT), because such animals bring a wealth of historic data that is linked to a large number of other industry flocks, so adding considerable value to the data to be generated and in return being able to be directly linkable to a wide range of industry flocks. A number of sires from outside the databases were chosen to provide access to some additional bloodlines. Secondly, each individual sire was chosen for particular meat, wool or sheep characteristics, with the sires chosen typically leaders in one or more of these traits. It should be noted that this is neither a breed nor sire evaluation. Certain breeds and sires were chosen in the first year to be broadly representative of industry, but the breeds, numbers and stud origin will vary to ensure diversity, and to generate the range of data required to develop breeding values and tests applicable to wider industry.
What will be done with the progeny?
The progeny will be evaluated for phenotypes for a large number of growth, carcase, meat, wool, reproduction and parasite-related traits, with about half of the wethers going for slaughter. The crossbred lambs will be grown out and slaughtered in processing plants with industry partners.
Detailed information on carcase and meat traits, meat yield and samples for laboratory testing will be collected. The MxM progeny will be evaluated for a wide range of wool traits and the wethers will be subsequently slaughtered for carcase and meat evaluation.
The MxM and BLxM ewes will be retained and mated naturally to evaluate reproduction traits. Blood and tissue samples will also be collected for genotyping and the molecular genetic studies. The first matings of the Information Nucleus occurred in early 2007 so that progeny are available for evaluation in the first year of operation of the CRC for Sheep Industry Innovation.